添加剂与转晶文献1
2021三聚氰胺对CaOx成核、晶体生长和晶型转化的影响范文2
2021三聚氰胺对CaOx成核、晶体生长和晶型转化的影响范文 引言 “宠物食物污染”和“三鹿奶粉”事件相继发生,其相关实验证明三聚氰胺能导致泌尿系结石形成. 但到目前为止, 三聚氰胺导致肾结石的形成机理尚未完全明了. 由于尿石中 70%~80%的晶体成分是草酸钙(CaOx). 本文采用体外模拟方法研究了三聚氰胺对 CaOx 成核、晶体生长和晶型转化的影响, 这有利于弄清三聚氰胺对草酸钙结石形成的作用机制. 1、实验部分 1.1试剂 三聚氰胺、草酸钠、氯化钙、氯化钠等均为分析纯试剂,实验用水为二次蒸馏水, 人造尿则参照文献[8]方法配制(见表 1),其主要组成为 Na2SO4, MgSO4, NH4Cl, KCl, CaCl2, NaH2PO4,Na2HPO4, NaCl, Na2C2O4. 1.2仪器 XL-30型环境扫描电子显微镜(Philips 公司), XD2 型 X 射线粉末衍射仪(北京大学), 傅立叶变换红外光谱仪(Bruker 公司), pH-3C 精密 pH 计(上海雷磁仪器厂), XJZ100 型正置金相显微镜(南京东图数码科技有限公司), DDS-11A 型电导率仪(上海盛磁仪器有限公司), SB3200-T 型数控超声波清洗仪. 1.3实验方法 1.3.1三聚氰胺对 CaOx 晶体成核的影响 取4mL0.01mol·L-1CaCl2溶液, 加 42mL 的二次水, 然后在37℃下边磁力搅拌边缓慢加入4mL0.01mol·L-1Na2Ox 溶液, 立即测定溶液电导率. 每隔 30s 读取 1 次电导率值. 改变二次水体积, 加入三聚氰胺溶液, 使体系中三聚氰胺的浓度分别为0.06、0.12 和 0.18mmol·L-1, 在相同条件下进行比较研究. 1.3.2三聚氰胺对 CaOx 晶体生长的影响取 50mL 的 A 液, 加入一定量的三聚氰胺溶液(小于 2mL), 然后边搅拌边加入 50mL 的 B 液, 改变三聚氰胺的体积, 配制浓度为 0.06, 0.12 和 0.18mmol·L-1的三种溶液. 晶体培养按照文献[9], 在37℃下晶体生长 1d 后取出, 进行 SEM、XRD 和 FT-IR 等表征. 1.3.3三聚氰胺对 CaOx 晶体形貌和物相的影响。
添加剂对焦化过程中的矿物转变特征的影响研究
添加剂对焦化过程中的矿物转变特征的影响研究张鑫;张楠【摘要】为研究不同添加剂对煤炭焦化过程中矿物相变的影响,采用X射线衍射和SEM扫描电镜分析了在不同种类、含量添加剂的情况下,焦化产物中组分和含量的变化.研究结果表明,氧化钙(CaO)的添加,促使矿物中含钙物增加,并对焦炭的微观形貌有影响,但添加过多时会影响焦炭的强度;二氧化钛(TiO2)的添加,会使焦炭中锐钛矿的含量显著增大,同时使石英类和莫来石类矿物含量下降.【期刊名称】《山西化工》【年(卷),期】2017(037)003【总页数】3页(P17-19)【关键词】焦炭;焦化;添加剂;矿物成分【作者】张鑫;张楠【作者单位】中煤电气有限公司,北京 101300;北京宝林建筑安装工程有限公司,北京 102400【正文语种】中文【中图分类】TQ52;TD981煤炭资源在我国的工业体系中占据着极其重要的地位，在发电、炼钢、基础化工等领域具有不可替代的优势。
炼焦过程一般用于焦化企业，其工艺流程为洗煤、配煤、炼焦和焦化处理[1]。
原煤成分复杂，矿物质的成分对焦炭的反应性、冷态强度等有很大的影响。
而在煤焦化过程中，矿物质种类、含量、化学状态的变化在微观上造成了焦炭微晶结构的堆积态不同，影响了焦炭的性能[2]。
国内外对焦化过程中的焦化相变过程及其规律进行了深入研究。
丁振华利用XRD和SEM研究了贵州某矿物的主要组成和含量[3]。
高志宏等人研究了矿物质在升温过程中的相变过程。
结果表明，在升温时，矿物中的氧化铝和氧化硅逐步转变为莫来石，且含量随升温而持续增加[4]。
焦化过程中，部分矿物质的加入可以催化碳素溶损反应，改善焦炭的反应性。
本文研究了不同种类的添加剂对焦炭焦化反应过程中矿物相变的影响，所得结果可为改进高灰分煤焦化工艺的生产提供参考。
取山西某地的某煤样为实验原料，其组分分析如表1所示。
所选用的添加试剂为分析纯CaO、TiO2。
1.2 实验工艺称取一定量的矿物样品(本次为1 kg)，按照不同比例与添加试剂混合，与10%的水分混合均匀,将煤样压实，放在小型的炼焦炉中。
多晶型与添加剂之经典文献3
Journal of Crystal Growth 235(2002)471–481Stabilization of a metastable polymorph of sulfamerazine bystructurally related additivesChong-Hui Gu a,c ,Koustuv Chatterjee a ,Victor Young Jr.b ,David J.W.Grant a,*aDepartment of Pharmaceutics,College of Pharmacy,University of Minnesota,Weaver-Densford Hall,308Harvard St.S.E.,Minneapolis,MN 55455-0343,USAbDepartment of Chemistry,University of Minnesota,207Pleasant St.S.E.,Minneapolis,MN 55455,USAcBristol-Myers Squibb Co.,1Squibb Drive,P.O.191,New Brunswick,NJ 08903,USAReceived 30April 2001;accepted 8October 2001Communicated by A.A.ChernovAbstractThe influence of structurally related additives,namely N4-acetylsulfamerazine (NSMZ),sulfadiazine (SD)or sulfamethazine (SM),on the rate of the solvent-mediated polymorphic transformation (I -II)of sulfamerazine in acetonitrile (ACN)at 241C was studie d.Thetransformation rateis controlle d by thecrystallization rateof themore stable Polymorph II.All three impurities exhibit inhibitory effects on the crystallization of Polymorph II and hence stabilize the metastable Polymorph I in ACN suspension.The rank order of the inhibitory effect (NSMZ b SD>SM)is thesameas therank orde r of thebinding e ne rgy of theimpurity mole culeto thesurfaceof thehost crystal.The relationship between the concentration of the impurity and the inhibitory effect was fitted to various models and was found to be best described by a model based on the Langmuir adsorption isotherm.r 2002Published by Elsevier Science B.V.Keywords:Al.Adsorption;puter simulation;Al.Crystal structure;A1.Impurities;A1.Nucleation;A2.Growth from solutions1.IntroductionPolymorphs arecrystallinesolids with thesame chemical composition but with different arrange-ments and/or conformation of the molecules in a crystal lattice.The discovery and characterization of polymorphs areimportant in various fie lds,because different polymorphs exhibit significantlydifferent physicochemical properties.In the phar-maceutical field,for example,the sudden appear-anceof a morestablepolymorph,that was not discovered at the early stage of pharmaceutical development,can cause loss of time and resources [1].Solvent-mediated polymorphic transformation is an efficient method to prepare more stable polymorphs [2,3].Traceamounts of a structurally related impurity may exert significant effects on thekine tics of dissolution [4]and crystallization [5],leading to changes in the polymorphic transformation rate in solution.Such effects may delay the discovery of a more stable polymorph.*Corresponding author.Tel.:+1-612-624-3956;fax:+1-612-625-0609.E-mail address:grant001@ (D.J.W.Grant).0022-0248/02/$-see front matter r 2002Published by Elsevier Science B.V.PII:S 0022-0248(01)01784-5On the other hand,the presence of an impurity or additivemay assist thepre paration of theme ta-stablepolymorph,which may othe rwiserapidly transform to themorestablepolymorph [6].To exploit the superior properties of a metastable polymorph,additives may be used to stabilize kinetically the metastable polymorph by inhibiting the formation of more stable polymorphs.There-fore,it is important to understand the effects of impurities or additives on the polymorphic trans-formation ratein solution.Thetransformation from theme tastablePoly-morph I of sulfamerazine (SMZ)to the more stablePolymorph II at 241C (room temperature)was chosen as the model system,while N4-acetylsulfamerazine (NSMZ),sulfadiazine (SD),and sulfamethazine (SM)were each chosen in turn as theimpurity (Sche me1).2.Materials and methods 2.1.MaterialsSulfamerazine (SMZ,4-amino-N-[4-methyl-2-pyrimidinyl]benzenesulfonamide,Lot #47H0114,purity >99.9%),SD,and SM were purchased from Sigma Co.(St.Louis,MO).Polymorphs I and II of SMZ were prepared as described in a previous paper [3].HPLC grade acetonitrile (ACN)was purchased from Fischer Scientific (Pittsburgh,PA).Residual water in ACN wasminimized by adding molecular sieves and anhy-drous calcium sulfate (Drierite,Hammond,Xenia,OH).N4-acetylsulfamerazine (NSMZ,4-acetamido-N-[4-methyl-2-pyrimidinyl]benzene-sulfonamide)was synthesized as described by Roblin and Winneck [7].The starting materials,namely acetylsulfanilyl chloride and 2-amino-4-methyl-pyrimidine,were purchased from Aldrich Chemi-cal Co.(Milwaukee,WI).The final precipitated product was recrystallized twice from tetrahydro-furan.The water content of NSMZ,determined by Karl Fischer titrimetry,was 6.3%(w/w),which corresponds to the monohydrate [theoretically 5.6%(w/w)water].Dehydration was achieved by storing at zero humidity for 2weeks.The anhydrate form of NSMZ (water content o 0.5%,w/w)was used in the later experiments.2.2.Solvent-mediated polymorphic transformationThetransformation from theme tastablePoly-morph I to Polymorph II at 241C was studied in ACN [3].Polymorph I was suspended in its presaturated solution containing a known amount of an impurity at 241C.Thewe ight/volumeratio of suspended solid to solvent was 20mg/ml.The suspension was shaken by a wrist-action shaker (Model 75,Burrell,Pittsburgh,PA)at B 300strokes/min.A portion of the suspension was withdrawn and filtered at designated times and the polymorphic composition of thesolid phasewasS NHOONNC H3NH 2C H 3S N HOONN NH 2S NHOO N NC H 3C H 3C ONHsulfamerazine (SMZ)N4-acetylsulfamerazine (NSMZ)sulfamethazine (SM) sulfadiazine (SD)Scheme 1.Molecular structure of the host molecule,SMZ,and the impurity molecules,NSMZ,SD,SM.C.-H.Gu et al./Journal of Crystal Growth 235(2002)471–481472determined by powder X-ray diffractometry (PXRD,Siemens D5005,Germany),which was described in detail in the previous reports[3,8]. Meanwhile,the concentration of SMZ in the solution during thetransformation proce ss was determined at l¼307nm with a spectrophot-ometer(DU7400,Beckman,Irvine,CA)[9].The standard solution contained the same concentra-tion of theimpurity as thesolution in which SMZ was suspended.To determine the crystal growth rate of Form II, 270mg(90%)of Polymorph I and30mg(10%)of Polymorph II were geometrically mixed and were suspended in the solutions described above,to determine the polymorphic transformation rate. This high proportion of seeds(10%of II)obviated the primary nucleation step in the transformation. Thepolymorphic transformation rateso de te r-mined corresponded to the crystal growth rate of themorestablePolymorph II in solution[3].2.3.Scanning electron microscopy(SEM) Themorphology was analyze d by SEM(S-800, Hitachi,Tokyo,Japan)at an accelerating voltage of10kV.The samples were sputter-coated with platinum to a thickness of50(A.2.4.Calculation of the impurity–surface binding energyTheinte raction of theimpurity with a growing surfacemay becalculate d,assuming that the solvent has no effect on the available conforma-tions of the impurity molecule[10].Commercial software(Ce rius2t,Molecular Simulation Inc. San Diego,CA)was employed to calculate the binding energy of the impurity molecule to the crystal surface.The Dreiding2.21forcefield was used to minimize the structure and to calculate the energy.For purposes of comparison,the binding energy of one molecule of each impurity to afixed and defined crystal face was calculated according to the procedure described by Jang and Myerson [10].The binding energy was obtained by sub-tracting the energy of the impurity molecule in the corresponding conformation from the minimum total energy of the surface bound with a single impurity molecule.3.Results and discussion3.1.Inhibitory effect of impurities on the transformation of SMZ Polymorph I to Polymorph II in ACN suspensionSolvent-mediated transformation consists of three consecutive steps:dissolution of the less stablepolymorph;nucle ation of themorestable polymorph;and crystal growth of themorestable polymorph.Theimpurity may affe ct any or all of these three steps.It was found in a previous study that thetransformation ratein pureACN is controlled by the crystallization rate of SMZ Polymorph II[3].To determine the rate-limiting step in the presence of the impurity,the concen-tration of SMZ in thesolution was monitore d.The concentration vs.time profile(Fig.1)indicated that thetransformation ratein thepre se nceof impurity is still controlled by the crystallization rate of Polymorph II,because the concentration of SMZ was closeto thesolubility of theme tastable Polymorph I until all Polymorph I in thesuspe n-sion had transformed to Polymorph II.In the presence of impurity,both the nucleation rate and crystal growth rate(Table1)were reduced significantly.However,the effect of NSMZ is 01234560102030Time (h)Conc.ofSMZinsolution(mg/ml)Fig.1.SMZ concentration–time profile during polymorphic transformation(I-II)in ACN solution containing the impurity,NSMZ(E)or SM(’)or SD(m),at molefraction 1.71Â10À5.C.-H.Gu et al./Journal of Crystal Growth235(2002)471–481473much greater than that of SM and SD.The morphology of SMZ Polymorph II grown from solutions containing each of these impurities is shown in Fig.2.Themorphology of SMZ grown in the presence of SM or SD is similar to that grown in its absence.However,in the presence of NSMZ at a molefraction as low as3.43Â10À6, themorphology is change d to a plateshapewith dominant\001\faces.These results indicate that all three impurities inhibit the crystallization of SMZ Polymorph II and that therank orde r of the inhibitory effect is NSMZ b SD>SM.The rank order of the inhibitory effect of the impurity may be explained by examining the crystal structureof SMZ Polymorph II,which is shown in Fig.3[11].Theamino group on the phenyl ring serves as a hydrogen bond donor in thecrystal of Polymorph II.If a NSMZ mole cule substitutes for a SMZ molecule in the crystal lattice,the acetyl group of NSMZ,which has replaced a hydrogen atom in SMZ,will hence disrupt the hydrogen bond interaction with incoming SMZ molecules(Scheme1).Therefore, the rate of molecule incorporation,i.e.,the crystallization rate,will be reduced.In addition, at the nucleation stage,the incorporated impurity molecule may destabilize the molecular aggregates and facilitate the dissolution of the aggregate, resulting in a reduction of the nucleation rate.In this way,the nucleation and crystal growth process can be greatly disrupted by NSMZ.However,SM and SD differ from SMZ only in the methyl group on thepyrimidinering,which doe s not participate in the hydrogen bonding interaction.Therefore, SM and SD are less effective in inhibiting the crystallization process than is NSMZ.The inhibitory effect of the impurity does not follow therank orde r of themole cular sizeof the impurity.The molecular volumes and mole-cular surface areas of the impuritymolecules, Fig.2.Morphologies of the crystals of SMZ Polymorph II grown from ACN in the presence of impurities,NSMZ,SM,and SD.The molefraction of theimpurity in thesolution is1.71Â10À5.C.-H.Gu et al./Journal of Crystal Growth235(2002)471–481475respectively,are:NSMZ,244.6(A3,295.4(A 2;SM,225.1(A3,275.2(A 2;SD,196.3(A 3,233.4(A 2.3.2.Surface–impurity binding energyThe effects of impurities on crystallization kinetics are related to the strength of the inter-molecular interaction between the impurity and the terraces,steps,and kinks of the nuclei or crystals.Because crystal growth of SMZ in ACN follows theBCF me chanism,theimpurity inhibits crystal growth mainly by being adsorbed on to the steps and kinks.Chernov found that the decrease in step rate is proportional to the time when the kinks are free of impurities [12–14].If the lifetime of adsorbed molecules at kinks,steps,and terraces is shorter than the time required for the step to cover the interstep distance,impurities with great-er adsorption energy at kinks and steps are more likely to be adsorbed and thereby to inhibit the crystal growth.The adsorption energy at kinks and steps includes the adsorption energy on the terrace,which is proportional to the calculated solute–surface binding energy.The calculated solute and solvent binding energies (kcal/mol)to the crystal faces (001),(100),and (110),respec-tively,of SMZ Polymorph II are:NSMZ,À23.0,À20.4,À19.8;SM,À8.1,À14.5,À18.4;SD,À21.8,À17.6,À19.0;SMZ (host molecule),À19.5,À13.9,À12.2;ACN (solvent),À6.52,À6.13,À5.28.The greater the absolute value of the surface–impurity binding energy,the stronger the binding of impurity molecule to the surface,indicating higher probability of absorption on theste ps or kinks.The results show that all three impurities have greater binding energies to the individualcrystalFig.3.Crystal structure of SMZ Polymorph II [11].The dotted lines represent the hydrogen bonds.C.-H.Gu et al./Journal of Crystal Growth 235(2002)471–481476faces than does the host molecule,SMZ,and the solvent molecule,ACN,which supports the fact that all three impurities exert inhibitory effects. Among the three impurities,the binding energy of NSMZ is the greatest,followed by SD and then by SM,which is in agreement with the rank order of their inhibitory effects on both nucleation and crystal growth.Desolvation of both solute mole-cules and growth sites is an essential step in crystal growth.The difference in solvation energy be-tween the host molecule and the impurity mole-cule,compared to that at the growth sites,might also affect the binding preference of the solute molecules during crystal growth.This effect is neglected when the binding energy is compared.3.3.Relationship between the concentration of the impurity and the inhibitory effect on crystallization Several models have been developed to describe the dependence of the growth inhibitory effect of theimpurity on theconce ntration of theimpurity [15–19].The impurity molecules arefirst adsorbed onto the surface of a growing crystal,where they interfere with the further incorporation of SMZ molecules,causing the reduction in growth rate. Theamount of impurity adsorbe d onto thesurface may be described by the classical Langmuir adsorption isothermy¼kc1þkc;ð1Þwhere y is thefraction of thesurfacecove re d bythe impurity molecules,c is theconce ntration oftheimpurity in solution,and k is theratio of theadsorption rate coefficient to desorption ratecoefficient.If the adsorption of new molecules is subject toblocking by the adsorbed molecule or the surfacecontains unfillablevoids,themaximum proportionof the occupied area available for adsorption,y max;is less than unity(0o y max o1),corresponding to an empirical Langmuir equation[20].At equili-brium,the percentage of the surface coverage,y;may be expressed byy¼y max kc1þkc;ð2Þwhere y max is themaximum proportion of thesurfaceavailablefor adsorption,and theothe rparameters have the same meaning as definedpreviously.Because the classical Langmuir ad-sorption isotherm(Eq.(1))and the empiricalLangmuir adsorption isotherm(Eq.(2))have thesame form and therefore cannot be distinguishedwhe nfitting thedata,theclassical Langmuiradsorption isotherm is applied tofit the data inthe following models.The same value of thefittedparameters will be obtained when applying theempirical Langmuir adsorption isotherm tofit themodel,although thefitted parameters have differ-ent meanings.In order to model the inhibitory effect of theadsorbed impurity molecule on the crystal growth,the crystal growth mechanism needs to be deter-mined.The Jackson factor[5,21],a;may becalculated to estimate the growth mechanism bythefollowing e quation:a¼E sliceh k lE crystalD H sRT;ð3Þwhere E sliceh k lis the slice energy,E crystal is the energyof crystal formation,D H s is thehe at of solution,Ris thegas constant,and T is thete mpe rature[22].The a values are8.4for the(001)face,7.9for the(010)face,5.4for the(100)face,and6.5for theð1%11Þface[23].Be causethe a values are>5,crystal growth is likely to follow the BCFmechanism[5].Several established models fordescribing the dependence of the growth inhibitoryeffect on the impurity concentration[15–19]weretested byfitting to the experimental data[23].Boththe Cabrera–Vermileya model and the Kubota–Mullin model may describe the inhibitory effect ofimpurity on crystal growth following theBCFmechanism,but that proposed by Kubota andMullin[15]gave the bestfit to the experimentalresults.This equation for the latter model isf¼1Àe y;ð4Þwhere f is theratio of thecrystal growth ratein thepresence of impurity to that in its absence and e isthe inhibitory effectiveness factor of the impurity.The other symbols have the same meaning asdefined previously.In this model,the growth rateis assumed to be proportional to the step-C.-H.Gu et al./Journal of Crystal Growth235(2002)471–481477advancement velocity.The impurities are adsorbed onto a linear array of active sites of steps to inhibit the step advancement.The inhibitory effect,e ;is determined by both the size of the impurity molecule and the strength of interaction between theimpurity and thecrystal surface .Be cause 0o y max p 1;when e >1and theconce ntration of impurity is high enough to make y ¼y max ;crystal growth may be blocked completely when the e y X 1:However,when e o 1;thecrystal growthrate will be reduced maximally to a value equal to (1Àe ),and the dependence of the inhibitory effect on the concentration of the impurity will level off at high concentrations of the impurity.Rearran-ging Eq.(4)with inserting Eq.(1)gives the following linear expression:1=ð1Àf Þ¼ð1=ek Þð1=x Þþð1=e Þ;ð5Þwhere x is themolefraction of theimpurity in the solution and theothe r symbols havethesame(a)(b)x (mole fraction)x (mole fraction)0.00000.00020.00040.00060.00080.00100.00120.00.20.40.60.80.00.20.40.60.8F r a c t i o n o f n u c l e a t i o n r a t e ( f )F r a c t i o n o f c r y s t a l g r o w t h r a t e ( f )Fig.4.Fitting of the experimental data to Eq.(4),which describes the model proposed by Kubota and Mullin [11].The lines are drawnbased on the parameters determined by Eq.(5),and the symbols represent the experimental results.(a)Fitting of the crystal growth data;and (b)fitting of the nucleation data.The impurities are NSMZ, ;SD,.;and SM,J .C.-H.Gu et al./Journal of Crystal Growth 235(2002)471–481478meaning as defined previously.The data in Table1 werefitted to Eq.(5)to determine the values of k and e(Table2).Thefit of thedata to Eq.(4)is shown in Fig.4a.The e valuefor NSMZ is slightly>1,which indicates that the crystal growth may cease completely when the concentration of NSMZ is high enough,at which point y is closeto unity.We found that,when the concentration of NSMZ reaches3.26Â10À4molefraction,thetransforma-tion virtually ceases.At this concentration,the model also predicts that the crystal growth rate will be equal to zero,which is in agreement with the experimental observations.In the presence of SM or SD,the e values are o1,which means that the maximum extent of reduction in the crystal growth rate by these two impurities is(1Àe).TheKubota–Mullin mode l predicts that the minimum crystal growth rate in the presence of SM or SD is27%or22%, respectively,of that in their absence.In Table1, the conversion time in the presence of SM reaches a plateau,2h,despite the increase of the SM concentration.This maximum time corresponds to theminimum growth ratein thepre se nceof SM, which is25%of thegrowth ratein its abse nce.In the presence of SD,the plateau value is2.25h, corresponding to22%of the growth rate in its absence.The predicted value agrees with the experimental value.In Table2,the rank orders of the values of k and e follow the rank order of the inhibitory effect and the rank order of the surface–impurity binding energy.The k value is directly related to the surface–impurity binding energy by the Arrhenius equation[24].The value of the effectiveness factor, e;is related to the strength of the interaction between the impurity molecule and the crystal surface,which may reflect the surface–impurity binding energy[25].Therefore,the calculated surface–impurity binding energy may serve to screen the inhibitory effect of the impurity. Unlike the mechanism for impurity effect on the crystal growth rate,the dissolved impurity may reduce the nucleation rate by occupying the active sites on prenuclear aggregates,thereby inhibiting their growth beyond the critical size of a stable nucleus,and/or by becoming incorporated into the prenuclear aggregates or nuclei,thereby disrupting them and facilitating their dissolution.If the impurity acts primarily by inhibiting thegrowth of prenuclei,the models for crystal growth may be applied to describe the relationship between the concentration of the impurity and the inhibitory effect on nucleation.However,if the impurity acts primarily by its incorporation,there lationship between the segregation coefficient and the con-centration of the impurity must be known to model the dependence of the inhibitory effect on theimpurity conce ntration.In this study,the relative nucleation rate is estimated by the reciprocal of the induction time (Table1).When the inhibitor prevents the molecular aggregates from growing into stable nuclei,the relationship between the concentration of theimpurity and there duction in nucle ationTable2Estimated parameters of the Kubota–Mullin model[15]for crystal growth inhibition based on Eq.(5)NSMZ SM SD Langmuir(Eq.(5))k 5.66Â105 4.55Â105 5.31Â105e 1.020.7280.781 Estimated minimum crystal growth rate a00.270.22 Minimum experimental crystal growth rate b00.250.22a Theminimum crystal growth rateis theminimum ratio of thecrystal growth ratein thepre se nceof an impurity to that in its absence.b The minimum experimental crystal growth rate is the ratio of the growth time in the absence of impurity to that with the highest concentration of impurity(Table1).C.-H.Gu et al./Journal of Crystal Growth235(2002)471–481479ratemay bede scribe d by Eq.(4),in which f is the fraction of the nucleation rate in the presence of impurity to that in its absence.Fig.4b summarizes thefit to Eq.(4).Thefitting appears satisfactory,and the esti-mated minimum nucleation rates in the presence of various impurities agree with the experimental values.These results suggest that the impurity may retard the nucleation of Polymorph II by inhibit-ing the growth of the molecular aggregates. However,the experimental results do not exclude thepossibility that theimpurity may beincorpo-rated into the host lattice in the form of prenuclei and destabilizes them.With increasing concentra-tion of theimpurity in thesolution,theamount of incorporated impurity may reach a maximum, corresponding to the solid solubility limit of the impurity in thehost crystal[26].This maximum incorporation may also explain the constancy of the inhibitory effect at higher concentrations of SM and SD.The solid-state relationship between thehost crystal and theimpurity mole culewill be studied to examine the possibility of solid solution formation.4.Conclusions1.Structurally related additives significantly in-hibit thetransformation of Polymorph I of SMZ to Polymorph II in suspension in ACN, by inhibiting both thenucle ation and thecrystal growth of themorestablePolymorph II.2.The rank order of the inhibitory effect isN4-acetylsulfamerazine(NSMZ)b sulfadiazine (SD)>sulfamethazine(SM).This rank order agrees with the rank order of the binding energy of theimpurity to thecrystal surface.3.The relationship between the inhibitory effectand theconce ntration of theimpurity is be st described by a model proposed by Kubota and Mullin[15,16].When the concentration of NSMZ is sufficiently high(>6.86Â10À5mole fraction for nucleation or>3.26Â10À4mole fraction for crystal growth),both thenucle ation rateand thecrystal growth ratebe come negligible.However,in the presence of SD or SM,the nucleation rate is maximally reduced to13%or29%,respectively,with respect to that in theabse nceof theimpurity.Thecrystal growth rate is maximally reduced to25%by SM or22%by SD with respect to that in its absence.Theimpurity e ffe ct on thestabilization of a particular polymorph should be considered during polymorph screening.Because the impurity may delay the discovery of a polymorph,it is necessary to repeat the screen for polymorphs after the chemical purity of the material has been opti-mized.On the other hand,stabilization of a metastable polymorph with superior physicochem-ical properties may be achieved by adding an acceptable additive with a suitable binding energy. The kinetic models discussed in this paper may be used to estimate the concentration of the additive necessary to achieve stabilization of the metastable phase over the shelf life of a product. AcknowledgementsWethank Bristol–Mye rs Squibb for an unre st-ricted grant and also the Supercomputing Institute of the University of Minnesota forfinancially supporting our use of the Medicinal Chemistry/ Supercomputing Institute Visualization F Work-station Laboratory.References[1]S.R.Chemburkar,et al.,Org.Process Res.Dev.4(2000)413.[2]N.Rodriguez-Hornedo,D.Murphy,J.Pharm.Sci.88(1999)651.[3]C.H.Gu,V.Young Jr.,D.J.W.Grant,J.Pharm.Sci.90(2001)1878.[4]H.Bundgaard,J.Pharm.Pharmacol.26(1974)535.[5]J.W.Mullin,Crystallization,3rd Edition,Butterworth-Heinemann,London,UK,1993.[6]R.Vrcelj,H.Gallagher,J.Sherwood,J.Am.Chem.Soc.123(2001)2291.[7]R.O.Roblin Jr.,P.S.Winneck,J.Am.Chem.Soc.62(1940)2002.[8]G.Zhang,Influence of solvents on properties,structures,and crystallization of pharmaceutical solids,Ph.D.Thesis, Department of Pharmaceutics,University of Minnesota, Minneapolis,MN1998,pp.70–122.C.-H.Gu et al./Journal of Crystal Growth235(2002)471–481 480[9]R.D.G.Woolfender,in:K.Florey(Ed.),AnalyticalProfiles of Drug Substances,Academic Press,New York, NY,1977,pp.515–517.[10]A.S.Myerson,S.M.Jang,J.Crystal Growth156(1995)459.[11]K.R.Acharya,K.N.Kuchela,J.Crystallogr.Spec.Res.12(1982)369.[12]A.A.Chernov,in: A.V.Shubnikov(Ed.),Growth ofCrystals,3rd Edition,Consultant Bureau,NY,1962,p.31.[13]A.A.Chernov,p.4(1961)116.[14]A.A.Chernov,Modern Crystallography III CrystalGrowth,Springer,Berlin,1984,p.162.[15]N.Kubota,J.W.Mullin,J.Crystal Growth152(1995)203.[16]N.Kubota,M.Yokota,J.W.Mullin,J.Crystal Growth182(1997)86.[17]M.C.van der Leeden,D.Kashchiev,G.M.van Rosmalen,J.Crystal Growth130(1993)221.[18]R.J.Davey,J.Crystal Growth34(1976)109.[19]N.Cabrera,D.Vermilyea,in:B.Doremus,B.W.Roberts,D.Turnbull(Eds.),Growth and Perfection of Crystals,Wiley,New York,NY,1958,p.393.[20]Z.Adamczyk,B.Siwek,M.Zembala,P.Belouschek,Adv.Colloid Interface Sci.48(1994)151.[21]K.A.Jackson,Liquid Metals and Solidification,AmericanSociety of Metals,Cleveland,OH,1958.[22]P.Bennema,J.Phys.D26(1993)B1.[23]C.H.Gu,Influence of solvent and impurity on thecrystallization process and properties of crystallized product.Ph.D.Thesis,Department of Pharmaceutics, University of Minnesota,Minneapolis,MN,2001.[24]M.Rauls,K.Bartosch,M.Kind,S.Kuck,cmann,A.Mersmann,J.Crystal Growth213(2000)116.[25]N.Kubota,M.Yokota,J.W.Mullin,J.Crystal Growth212(2000)480.[26]Z.J.Li,D.J.W.Grant,Int.J.Pharm.137(1996)21.C.-H.Gu et al./Journal of Crystal Growth235(2002)471–481481。
壬二酸多晶型及其转晶过程研究
壬二酸多晶型及其转晶过程研究
壬二酸是一种重要的工业化学原料，也被广泛用于医药、涂料和塑料
等领域。
其中，壬二酸多晶型和其转晶过程是研究的热点和难点之一。
壬二酸多晶型是指在合成壬二酸的过程中，由于条件的不同，可能得
到不同形态的晶体，其中多晶型是最常见的一种。
壬二酸多晶型的研
究对于探究壬二酸的物理性质、结构和应用具有重要意义。
当前，学者们已经探索了多种制备壬二酸多晶型的方法，其中最常见
的一种是通过溶剂热法。
这种方法是将壬二酸放入特定的有机溶剂中，在加热条件下使其晶化形成多晶型。
另外，学者们还研究了壬二酸多晶型的转晶过程，即将多晶型转化为
单晶型。
壬二酸多晶型转晶过程的研究可以帮助人们更好地理解晶体
的组成和结构，并有可能应用于提高壬二酸的纯度和结晶度。
目前，学者们已经在壬二酸多晶型转晶过程的研究中取得了一定的成果。
研究表明，将壬二酸多晶型放入高温高压条件下，可以利用氢氧
根离子的存在促进其转晶成为单晶型。
此外，壬二酸单晶的研究也取
得了一些进展，比如利用特定的有机溶剂或添加剂来制备壬二酸单晶。
总的来说，壬二酸多晶型及其转晶过程的研究已经引起了越来越多学者的关注。
未来，随着研究深入以及新技术的出现，相信壬二酸多晶型和单晶型的制备和应用将会得到更加广泛和深入的研究。
药物水合物结晶热力学及转晶过程研究
药物水合物结晶热力学及转晶过程研究本文首先介绍了与药物水合物结晶人力学及转晶过程有关的一系列理论，指出了水合物药物的代表——茶碱与卡马西平的特点及应用范围，在此基础上，以茶碱为例，从实验的角度入手，重点分析了药物水合物结晶热力学及转晶过程，最终得出了相应结论，明确了茶碱晶型水活度及溶解度等与温度之间的关系，仅供参考。
标签：药物水合物；结晶；热力学；转晶过程水合物属药物的主要形式之一，目前来看，超过30%的药物都以水合物的形式存在。
水合物结晶力学及转晶过程，对药物性能的稳定发挥影响较大，应对其加以分析，以提高药物生产工艺流程合理性，确保药物功能顺利发挥。
1 理论综述1.1 多晶体与溶剂化物1.1.1 多晶体化学物质多以固体形式存在，在固体的化学物质中，其离子与分子的功能，呈周期性排列，所形成的有序的状态，便称为晶体，而同一种化学物质，如存在两种或以上的排列方式，则称为多晶体。
1.1.2 溶剂化物溶剂化物指的是化合物分子与一种或多种溶剂分子，以一定的形式相结合组成的晶体物质。
在药物生产过程中，存在冷冻及干燥等过程，溶剂化物便在上述过程中产生，如其在产生过程中，出现了结晶现象，同样容易出现晶体。
1.2 水合物药物1.2.1 茶碱茶碱（theophylline）属多晶体药物的一种，是常见水合物药物之一，熔点高，微溶于乙醚，具有强心利尿的功能，在治疗心脑血管疾病方面，疗效显著，目前已经被医学界应用到了大量心脑血管疾病药物的生产过程中。
1.2.2 卡马西平卡马西平同属于多晶体药物的一种，为白色结晶或结晶性粉末，临床常用于神经性疼痛的治疗，同样可用于精神类疾病的治疗。
通过上述问题可以看出，多晶体药物活性较强，临床应用价值较高，对该部分药物水合物结晶热力学及转晶过程的研究，有利于进一步了解该种药物的治疗机制，对于医学界而言，意义重大。
2 药物水合物结晶热力学及转晶过程研究文章本部分从实验的角度入手，研究了药物水合物结晶热力学及转晶过程。
碳酸钙的晶型转化及其在磺酸盐润滑油清净剂中的应用进展_马晓东
质点在晶体构造中较为相似， 因此较易均匀地进入 2+ 晶体内部， 使晶体的构造发生变化， 如 Mg 可进入
2+ 而不能进入文 方解石的晶格取代 Ca 离子的位置，
石的晶格， 因此主要诱导生成文石型碳酸钙
［7 ， 15 ］
。
文献报 道 的 无 机 盐 型 晶 型 调 控 剂 主 要 有 ZnSO4 、 BaCl2 、 AlCl3 等， 见表 1 ， 所得到的碳酸钙晶型有板 状、 针状、 纺锤状等不同形态
2013 年 4月 Apr． 2013
润滑油
LUBRICATING OIL
第 28 卷 第 2 期 Vo l． 28 ， No． 2 3119（ 2013） 02002806 文章编号： 1002-
碳酸钙的晶型转化及其在磺酸盐润滑油 清净剂中的应用进展
马晓东， 刘功德， 曹聪蕊
（ 中国石油大连润滑油研究开发中心， 辽宁 大连 116032 ） 摘要： 结晶型碳酸钙有方解石 、 球霰石和文石三种形态， 无定型碳酸钙在有机酸 、 无机酸及其盐等转化剂的作用下可分别得到 上述三种晶型， 且通过控制转化剂的类别 、 溶剂体系、 转化温度等实现碳酸钙粒径大小及分布的调控 。 文章总结了碳酸钙晶型 并分析了影响碳酸钙形貌的因素 。 此外， 鉴于碳酸钙晶型、 粒径大小及分布对磺酸盐清净剂使用性能的重要影 转化的方法， 响， 文章还综述了磺酸盐清净剂中碳酸钙的晶型转化及调控研究进展 。 关键词： 碳酸钙； 晶型转化； 磺酸盐； 清净剂 中图分类号： TE624． 82 文献标识码： A
0
引言
碳酸 钙 ห้องสมุดไป่ตู้ 六 种 存 在 形 态 ， 不含水晶型（ 方解 石、 球霰石和文石 ） ， 含水晶型 （ 单水碳酸钙和六水 碳酸钙 ） ， 以 及 无 定 型 碳 酸 钙 （ 见 图 1 ） 。 其 中， 最 具有菱形晶胞 ， 在自然界 稳定的晶型是方解石型 ， 广泛应用于冶金 、 材料 、 建筑等 和生物体中最常见 ， ［1 － 3］ 。 无定型碳酸钙热稳定性最差 ， 领域 通常作为 ［4 － 5］ 、 晶体的前驱体 ， 在晶型控制剂如有机酸 生物 ［6］ 2+ 2+ ［7 － 9］ Ba 等阳离子的无机盐 大分子 、 含 Mg 、 等 影响下形成不同形态及分布的碳酸钙晶粒 。 磺酸 盐类清净剂是一类应用极为广泛的润滑油添加剂 ，
α成核剂二(苯亚甲基)山梨醇及其含量对PP制品的晶体结构和力学性能的影响
毕业设计（论文）题目：α成核剂二(苯亚甲基)山梨醇及其含量对PP制品的晶体结构和力学性能的影响学生姓名：系别：科院材工系专业：高分子学号：班级：指导老师：摘要本课题采用差示扫描量热法分析了α成核剂二（苯亚甲基）山梨醇对聚丙烯（PP）的结晶性能的影响，采用偏光显微镜观察了结晶尺寸大小的变化，并测试了聚丙烯的力学性能。
结果表明：加入少量α成核剂提高了聚丙烯的结晶温度和结晶度，且随着α成核剂的添加，聚丙烯的球晶尺寸明显缩小，聚丙烯的拉伸强度也相应争强，当α成核剂质量分数为0.4%时，拉伸强度最大，同时添加少量的α成核剂可提高PP的弯曲强度。
但是由于样品的结晶度明显增加，成为导致冲击性能较为减弱的主要原因。
关键词：聚丙烯；α成核剂；结晶性能；力学性能ABSTRACTThis topic by differential scanning calorimetry analyzes the α nucleating agent 2 (benzene methylene) sorbitol polypropylene (PP) on the crystallization of the influence of performance by using polarizing microscope crystallization of the size changes, and tests the polypropylene mechanics performance. The results show that the addition of a few α nucleating agent improve the crystallization temperature and crystallinity of polypropylene, along with α nucleating agent to add, PP spherulite decrease the size, the tensile strength of the polypropylene also raised the corresponding, when alpha nucleating agent quality score is 0.4%, the largest tensile strength, and adding a few alpha nucleating agent can improve the PP bending strength. But because the sample, the crystallinity of increased significantly, the impact is to be the main reason for the performance weakened.Keywords:polypropylene, α nucleating agent, Crystal properties, Mechanical properties第一章概述1.1课题背景及意义聚丙烯(PP)是当今发展最快的通用树脂品种之一，其原料来源丰富、价格低廉、成型性好。
几篇电解液新型添加剂文献总结
Perfluoroalkyl-substituted ethylene carbonates: Novel electrolyte additives for high-voltage lithium-ion batteries Journal of Power Sources 246 (2014) 184-191
Methylene methanedisulfonate 甲烷二磺酸亚甲酯 CAS： 99591-74-9 1. MMDS可提高LNMC/C电池4.4V的 cycles性能，100cycles（ 70.7%→94.1%），但对4.2V电池 改善效果不明显。 2. MMDS高压下可在正极分解成膜， 降低LiF的含量，提高界面导锂新能 ，同时抑制LiPF6及电解液在正极表 面的分解。
1. 添加0.2wt%TPPA，可优先溶剂在 LCO表面成膜，阻止电解液及锂盐 的分解，提高其工作电压到4.4V， 且对负极MCMB没有影响。
供应商
纯度
价格
Aldrich
Alfa 百灵威
97
97 97
1372.41元/5g
1374元/5g 679元/5g
电导率 RF EL 10.8 10.7
分解电压 4.7V 3.6V
Electrolyte Additive in Support of 5 V Li Ion Chemistr——徐康 Journal of The Electrochemical Society,158（3）A337-A342（2011）
Tris(1,1,1,3,3,3hexafluoroisopropyl) phosphate 三（六氟异丙基）磷酸酯 CAS：66489-68-7
Li1.2Mn0.54Ni0.13Co0.13O2：2.5-4.8V，0.1C首次充电；2.5-4.6V，0.5C 100cycles,189.5mAh/g(81.3%)；150mAh/g(5C)、90mAh/g(10C)
功能添加剂对石膏凝胶晶体生长习性影响的研究进展
１ 缓 凝 剂 对 石 膏 晶体 微 观 形 貌 的 影 响
石 膏缓 凝 剂主要 用 来 降低石 膏凝 结速 度 。缓
凝 剂大 致 分 为 ： 有机 酸类 、 无 机 盐类 、 蛋 白 质 类
结 硬化 非 常缓 慢 ， 导致 其利 用率 低 ， 适 当 的激 发 剂 能 提高 硬石 膏水 化 率 ， 从 而 拓宽 其 应 用 范 围 。石
长 的 影 响 各 不相 同 ， 但 成 形 石 膏 晶 体 之 间 的搭 接 均 变致 密 ， 降低 了水 膏 比 。 关键词 ： 石 膏 晶体 ； 缓凝剂 ； 激发剂 ； 防水剂 ； 减 水 剂
中 图分 类 号 ： ＴＱ １ ７ ７ ． ３
文献标识码 ： Ａ
文章编号 ： １ ０ ０ ８ — ０ ５ １ １ （ ２ ０ １ ５ ） ０ ２ — ０ ０ ６ ７ — ０ ７
晶体 的成 核 、 生 长过 程 ， 从 宏 观 上 改 善 石 膏性 能 ，
国 内研 究 者也 开始 进行 关 于添加 剂对 石膏 晶体 成 核、 生 长影 响 的 研 究 。作 者 根 据 石 膏添 加 剂 的 习 惯 分类 ， 综 述 了近 几 年 各 种 石 膏 添加 剂 对 石 膏 晶
综 述 专 论
Ｓ Ｃ Ｉ Ｅ Ｎ Ｃ Ｅ ＆ Ｔ Ｅ Ｃ Ｈ Ｎ Ｏ Ｌ ０ Ｇ Ｙ 化 Ｉ Ｎ 工 科 Ｃ Ｈ 技 Ｅ ， Ｍ ２ ０ Ｉ Ｃ １ ５ Ａ ， Ｌ ２ ３ Ｉ （ Ｎ ２ Ｄ ） ： Ｕ ６ Ｓ ７ Ｔ ～ Ｒ ７ Ｙ ３
功 能添 加 剂 对 石 膏 凝 胶 晶体 生 长 习性 影 响 的 研 究 进 展
石 膏基 材具 有 防火 、 低耗能、 透气、 绿色 环保 、
德 国、 日本 等 国相 继 研 发 了石 膏 体 系 专 用 减 水
添加剂对硅酸铝-SiC-C不定形耐火材料中纳米SiC晶须形成的影响
提 高 强 度 和 在 氧 化 条 件 下 的 耐 磨 性 。Ｂ ＳＣ结 合 —ｉ 对 强 度 的影 响还 没有 详 细解 释 。
一
般说 来 ，抗 折 强度 随着烧 成温 度 的升 高而增 （ １０Ｃ、 ｌ２ ０Ｃ、 １ ０￣ ０￣
大 ，而且在 给定 的温度
１ ３ ０ 、 ｌ５ ０Ｃ） 下 ， 金 属 硅 的 粒 度 增 大 到 ０％ ０￣
１０ ￣ 以上时 ，弹性模 量 降低 。对 于粗 Ｓ 粉 ，ＳＣ ０ｐ ｍ ｉ ｉ
的形 成 量 减少 ，这 意 味着 有 一 些 Ｓ 未 反应 。有 文 ｉ 章 指 出 ，滑 板 的强度 和耐用 性 可不通 过增 加金 属
倍。
关键 词 ：晶须；强度；Ａ２３ ｌ ；耐火材料 ０ 中图分 类 号 ：Ｔ １５ ３ Ｑ ７． ７ 文献 标 识码 ：Ａ 文章 编 号 ：１７—７２（０ １ ４ ０３—４ ６３ ７９ ２ １０—０４ ０
１ 前 言
钢 铁领 域 （ 如高 炉 的 出铁 和 出渣 沟 、炉底 以及 电炉 出 钢 口） 硅 酸 铝 一 ｉ — 用 ＳＣ Ｃ热 固性 树 脂 结 合 捣
然 而 ．通 过检 测 Ａ 在 耐 火 材 料 中 的行 为发 现 。Ａ ｌ ｌ
热 固性 结 合 剂 的优 点 包 括 ：环 境 友 好 、容 易 混 合 以及 高 残 碳 。热 固性 结 合 剂 的缺 点 为 ：在 约 ３０ ５０ ０ ～ ０ ％温 度 范 围 内 。丙 阶 酚醛 树 脂 结 构 （ 叫 也 聚合碳 ）热解 ，产 品变 差 。 如果 这 些 聚合 链 暴 露 在 官 能 团 发 生 反 应 的 条
添加剂与晶型之文献2
Colloids and Surfaces B:Biointerfaces17(2000)145–152Effect of binders on polymorphic transformation kinetics of carbamazepine in aqueous solutionMakoto Otsuka*,Tomoko Ohfusa,Yoshihisa Matsuda Department of Pharmaceutical Technology,Kobe Pharmaceutical Uni6ersity,Motoyama-Kitamachi4-19-1,Higashi-Nada,Kobe658,JapanReceived7June1999;accepted9July1999AbstractThe effects of binders on the polymorphic transformation kinetics of carbamazepine(CBZ)were investigated by thermal analysis and X-ray diffraction analysis.The binders used were hydroxypropylcellulose(HPC)(HPC-SL, molecular weight30000–50000;HPC-M,molecular weight50000–70000;HPC-L,molecular weight110000–150000).CBZ anhydrate form I and various concentrations of binder solutions were mixed at1000rpm and25°C. The amount of dihydrate transformed was evaluated based on the latent heat due to dehydration on DSC curves. Since thefirst-order plots for transformation process of CBZ showed a straight line,the transformation rate constant, k and induction period,IP were estimated based onfirst-order kinetics by the least-squares method.The k of CBZ decreased with increase of HPC-L concentration,but the IP increased.In contrast,the k of phase transformation on addition of crystal seeds was almost the same as that without seeds,but the IP significantly decreased on seed addition.The result suggested that IP was a nucleus formation process,but the seed addition did not affect the crystal growth process.The molecular weight effect of HPC on the transformation suggested that the k of HPC-SL was the largest,with the rank order being HPC-SL\HPC-M\HPC-L.The order for IP was HPC-L\HPC-SL\HPC-M. The relation between IP and kinematic viscosity had a straight line,but the k decreased with increase of kinematic viscosity.The increase of IP on addition of HPC might be induced by inhibition of the formation of nuclei by the steric intermolecular effect of HPC and decrease of D v.Therefore,HPC strongly inhibited nucleus formation in the crystallization of CBZ.©2000Elsevier Science B.V.All rights reserved.Keywords:Polymorphic transformation;Carbamazepine;Hydration;Nucleation;Crystal growth;Hydroxypropylcellulosewww.elsevier.nl/locate/colsurfb1.IntroductionHigh quality granular preparations offer a number of potential advantages to the pharma-ceutical industry in the production of beads or granules as bothfinished and intermediate prod-ucts.Therefore,various kinds of granulation tech-niques and equipment,such as extruders,fluidized beds and high speed mixers,have been developed to obtain high quality granular materials[1].Con-trolling these properties is an important factor in the production of high quality pharmaceuticals.*Corresponding author.Tel.:+81-78-441-7531;fax:+81-78-441-7532.E-mail address:m-otsuka@kobepharma-u.ac.jp(M.Otsuka)0927-7765/00/$-see front matter©2000Elsevier Science B.V.All rights reserved. PII:S0927-7765(99)00111-3M.Otsuka et al./Colloids and Surfaces B:Biointerfaces17(2000)145–152 146However,the pharmaceutical properties of gran-ules depend on various physical and chemical factors during manufacturing processes,such as instruments,formulations and manufacturing conditions.There is a few studies concerning to crystalline transformations during manufacturing process.The polymorphic form of an insoluble drug influences the bioavailability of preparations by affecting the dissolution rate[2].The physico-chemical stability related polymorphism affects the pharmaceutical properties,such as disintegra-tion time and mechanical strength of the prepara-tion[3].Carbamazepine(CBZ)is widely used as a potent anticonvulsant,and there have been re-ports concerning its polymorphic form[4–6]. CBZ polymorphic transformation at high humid-ity[7]and in aqueous suspension[8]was investi-gated and it was concluded that all forms transformed into the dihydrate.However,in a previous study[9],CBZ anhydrate form I was not transformed into dihydrate during CBZ granular formulation.This suggested that excipients,such as a binder,diluent and disintegrator,interacted with CBZ,and inhibited CBZ polymorphic trans-formation during granulation.In this study,there-fore,to clarify the interaction between excipients and CBZ,we investigated the effect of HPC as a binder on the polymorphic transformation of CBZ anhydrate.2.Materials and methods2.1.MaterialsCBZ bulk powder of Japanese Pharmacopoeia (JP)XIII grade(lot No.CEE-9-5)was obtained from Katsura Chem.Co.,Tokyo,Japan.The bulk powder was identified as being of polymor-phic form I[7]by X-ray diffraction analysis and DSC measurement.Hydroxypropylcellulose (HPC)(HPC-SL,molecular weight30000–50000;HPC-M,molecular weight50000–70000; HPC-L,molecular weight110000–150000;Ni-hon Soda Co.Japan)was used as a binder.All other chemicals were of analytical grade.2.2.Preparation of polymorphsThe CBZ bulk powder was identified as being of form I(anhydrate,monoclinic CBZ)[7].The dihydrate form(form IV)[7]was obtained by recrystallization as follows:the CBZ bulk powder was dissolved in50%ethanol solution in a water bath at70°C,andfiltered.After cooling the satu-rated CBZ solution to room temperature,the crystalline samples werefiltered and dried in a desiccator containing silica gel at room tempera-ture under vacuo for3h.All of the CBZ samples were passed through a no.200mesh(75m m) screen.2.3.Viscosity measurementThe kinematic viscosity was determined using a capillary viscometer at25°C(JP XIII).2.4.X-ray powder diffraction analysisDiffractograms were taken at room tempera-ture with an X-ray diffractometer(XD-3A,Shi-madzu Co.,Kyoto,Japan).The operating conditions were as follows:Target,Cu;filter,Ni; voltage20kV,current,20mA;receiving slit,0.1 mm;time constant,1s;counting range,1kcps; scanning speed4°2q min−1.2.5.Thermal analysisDifferential scanning calorimetry(DSC)was performed with a type3100instrument(Mac Sci-ence Co.,Tokyo).The operating conditions in the open-pan system were as follows:sample weight, 5mg;heating rate,10°C min−1;N2gasflow rate, 30ml min−1.2.6.Polymorphic transformation processA total of30g of CBZ bulk powder was mixed with200ml of0,0.001,0.005,0.05w/v%binder solution in a1000-ml round bottomedflask at a mixing speed of1000rpm at25°C.To evaluate the amount of dihydrate transformed5ml of suspension was sampled during mixing at5,10, 20,30,4560and85min,and afterfiltering theM .Otsuka et al ./Colloids and Surfaces B :Biointerfaces 17(2000)145–152147Fig.1.Powder X-ray diffraction profiles of CBZ forms.w /w%crystal content)in a mortar.The DSC curves of the standard samples were measured in triplicate.The standard deviation of the data was within 5%.The plots gave a good linear correla-tion and the linear regression equations were as follows:Y =308.4X +5.8(R =0.998)(1)where Y (J g −1)is a latent heat due to dehydra-tion of dihydrate CBZ.X is the dihydrate concen-tration (w /w%).R is the correlation coefficient.3.Results3.1.Effect of HPC -L concentration in binder solution on CBZ phase transformationFig.1shows the X-ray diffraction profiles of CBZ anhydrate,form I and dihydrate,form IV.The X-ray diffraction patterns of form I and dihydrate were significantly different and identical to those reported [6,7].Fig.2shows the effect of HPC-L concentration on the endothermic peak due to dehydration on DSC curves of CBZ dihy-drate.The endothermic peak of the samples in 0and 0.001%binder solution increased with mixing time,but not so in 0.05%solution.The X-ray diffraction profiles were consistent with this resultwet powders were stored at 30°C,47%RH for 24h to measure DSC.2.7.Measurement of the dihydrate contentThe dihydrate (form IV)content of the samples was measured by DSC based on the endothermic peak at around 70°C due to dehydration.Briefly,known quantities of standard mixtures were ob-tained by physically mixing anhydrate and dihy-drate at various ratios (0,25,50,75and 100Fig.2.Change of the DSC curves of CBZ forms during mixing (1000rpm)in binder solution at 25°C.M.Otsuka et al./Colloids and Surfaces B:Biointerfaces17(2000)145–152 148Fig.3.Effect of HPC-L concentration on hydration of CBZ form I. ,without additive; ,0.001%HPC-L; ,0.005% HPC-L; ,0.05%HPC-L.Fig.4.Effects of HPC-L concentration and the addition of seed crystals on thefirst-order plots for the hydration of CBZ form I. ,without additive; ,0.001%HPC-L; ,0.005% HPC-L; ,0.05%HPC-L; ,0.005%HPC-L with0.5% seeds.3.2.Effect of the molecular weight of the binder on CBZ phase transformationFig.5shows the effect of the molecular weight of HPC on CBZ phase transformation in aqueous suspension at25°C.The k and IP are summarized in Table1.The k of HPC-SL was the largest,with the rank order being HPC-SL\HPC-M\HPC-L.The(the data not shown).Thus,the CBZ anhydrate appeared to be transformed immediately to dihy-drate in aqueous suspension,but not in high binder solution.The amount of dihydrate transformed was evaluated based on the latent heat due to dehydration on DSC curves.Fig.3shows the effect of HPC-L concentration on the trans-formation of CBZ dihydrate.This suggested HPC-L inhibited the transformation of di-hydrate,and the effect depended on the concen-tration.Fig.4shows the effect of HPC-L on the first-order plots for polymorphic transformation of form I.Since the plot shows a straight line, the transformation rate constant,k and induction period,IP were estimated based onfirst-order kinetics by the least-squares method.The results are summarized in Table1.The k of CBZ de-creased with the increase of HPC-L concentra-tion,but the IP increased.In contrast,the k of phase transformation on the addition of crystal seeds was almost the same as that without seeds, but the IP significantly decreased on seed addi-tion.Table1Kinetic parameters for the transformation of CBZ aIP(min)k(min−1)Sample V(mm−2s−1)1.06×10−1 1.40 1.0000%binder0.001%HPC-L8.305.70×10−2 1.0060.005%HPC-L29.11.10×10−2 1.0261.04960.00.050%HPC-L02.63×10−226.70.005%HPC- 1.008SL0.005%HPC-14.76.10×10−3 1.018M1.0267.1431.41×10−20.005%HPC-L+seedsa k,transformation rate constant;IP,induction period;V, kinematic viscosity at25°C.M.Otsuka et al./Colloids and Surfaces B:Biointerfaces17(2000)145–152149 Fig.5.Effects of the molecular weight of HPC on thefirst-or-der plots for the hydration of CBZ form I. ,withoutadditive; ,0.005%HPC-SL; ,0.005%HPC-M; ,0.005%HPC-L.Fig.6.Effects of kinematic viscosity on the IP for hydration ofCBZ form I. ,without additive; ,HPC-L; ,HPC-M; ,HPC-SL.rank order for IP was HPC-L\HPC-SL\HPC-M.Since HPC-L has the highest molecular weight,the rank is HPC-L\HPC-M\HPC-SL, thus the k and IP were affected by the molecular weight of HPC.3.3.Effect of kinematic6iscosity on CBZ phase transformationFigs.6and7shows the effect of kinematic viscosity on the IP and k of CBZ transformation. The relation between IP and kinematic viscosity had a straight line,but that of k was a nonlinear and the k decreased with increase of kinematic viscosity.This suggested that the viscosity of the solution affected the crystal transformation kinet-ics of CBZ.4.Discussion4.1.Crystalline formation kineticsIn general,crystalline growth kinetics[11]con-sisted of nucleation and crystal growth and was controlled by various physical and chemical fac-tors.Eq.(4)shows nucleation velocity(J)based on Gibbs free energy change(D G)at constant temperature and pressure.The D G for formation of nuclei in radius r is expressed in Eq.(2),and dependent on D v and surface tension k.D G*is the formation of nuclei of clinical radius(r*) Fig.7.Effects of kinematic viscosity on the k for hydration of CBZ form I. ,without additive; ,HPC-L; ,HPC-M; , HPC-SL.M .Otsuka et al ./Colloids and Surfaces B :Biointerfaces 17(2000)145–152150Fig.8.Simulation curve of D G and J for the formation of nuclei upon crystallization based on Eqs.(3)and (4).The solid line and dotted lines represent D G and J ,respectively.The solubility is 10.ation,J ,increases with increase of D v ,the degree of supersaturation of solution,indicating that D v affects the D G and J of the crystallization process.Fig.9shows the effect of D v on the R max /J ratio of crystallization.The profile shows a maxi-mum peak at 1.3,and a decrease at values greater than D v =1.3(solubility =10).This suggests that the nucleation proceeds at higher D v ,but the crystal growth occurs at an D v of around 1.3after nucleation.Thus both nucleation and crystal growth proceed in more supersaturated solutions,but crystal growth occurs after nucleation at a lower degree of supersaturation.Young and Suryanarayanan [8]reported that CBZ anhydrate (form I)transformed into dihy-drate in aqueous solution following a first-order kinetics.In the present study,the crystalline trans-formation of CBZ anhydrate in aqueous solution also apparently followed first-order kinetics (Fig.4).However,the solid-to-solid transformation of CBZ during granulation is not simple crystalliza-tion,because it includes a starting material disso-lution process.In general,dissolution follows the Noiyes–Nernst Eq.(6).Kaneniwa et al.,[5]re-ported dissolution kinetics of CBZ form I based on the diffusion controlled dissolution model as shown in Eq.(6).−d C d t =DS wV l (C s−C )(6)D ,diffusivity of the drug;S w ,specific surface area;V ,volume of solution;t ,thickness of diffu-sion layer;C s ,solubility,C ,drug concentration at time t .obtained in Eq.(3).The J is affected through D G *by D v and k .D G (r )=4y r 33 D v +4y r 2k(2)D G*=4·4yk 3 23D v 2(3)J =4y r *2p q 1exp−D G*kT(4)where k ,surface energy; ,molecular volume;D v ,the degree of supersaturation of solution;s ,Boltzmann’s constant;m ,mass;r *,critical radius of nuclei;T ,absolute temperature;p ,concentra-tion of solution;q 1,density of critical nuclei at 0K.The crystal growth kinetics [11,12]is expressed as Wilson–Frenkel’s Eq.(5).Crystal growth rate,R max ,is also dependent on D v but independent of surface tension.R max = c 6aC e exp−D G dsl 8s T log(1+l )=D v(5)R max ,crystal growth rate; c ,molecular volume of crystal,a ,distance of crystal lattice;w ,vibration number of molecule;C e ,solubility of solution;D G ds ,Gibbs free energy of desolvation;|,degree of supersaturation;m ,mass.Fig.8shows the simulated results for nucle-ation based on Eqs.(3)and (4)at a constant temperature and pressure.The velocity of nucle-Fig.9.Simulation curve of D G /J for the formation of nuclei on crystallization based on Eqs.(3)and (4).The solubility is 10.M .Otsuka et al ./Colloids and Surfaces B :Biointerfaces 17(2000)145–152151Since there are several rate determination steps for crystalline transformation of CBZ,the crys-talline transformation in a suspension or during the kneading of wet mass for granulation consists of dissolution,nucleation and crystal growth as shown.Anhydrate Dissolutionk dSupersaturated solution Nucleationk nSS* Crystal growthk cDihydrate k d is the dissolution coefficient constant,k n is the nucleation rate constant and k c is the crystal growth rate constant.The SS*is activated super-saturated solution containing enough nuclei to start the crystal growth.Thus,the crystal trans-formation followed consecutive reaction kinetics,and included an induction period.4.2.Kinetic mechanism of inhibition of CBZ phase transformationIt is well known that polymer inhibits crystal growth in solution.Watanabe et al.[10]reported the inhibitory effect of sodium caseinate on the recrystallization of pheytoin from supersaturated solution.They concluded that the crystalline growth of phenytoin was inhibited by depression of the nuclei formation rate.On the other hand,the crystalline transformation of CBZ anhydrate apparently followed first-order kinetics,and was consistent with previous results.However,CBZ anhydrate in a formulation containing 0.05%HPC did not transform into dihydrate during granulation.Since the change of IP relative to viscosity was a linear (Fig.6),but that of k was non-linear (Fig.7),the mechanism of IP prolongation is not the same as that of depression of k .HPC might interact with CBZ,and inhibit crystallization of CBZ.On the other hand,the increase of viscosity on addition of HPC also might affect drug diffusion,D ,in dissolution (Eq.(6))and the activation energy of drug diffusion (D G ds )in crystal growth (Eq.(4)).This suggests that on increase of viscosity would induce a decrease of D v in the solution,and affect both the nucleation and crystal growth process.The results the effects of HPC con-centration (Fig.4)and molecular weight (Fig.5)effects are almost supported the theoretical hy-pothesis.The role of fine dihydrate crystals was investi-gated (see Fig.4).The k of 0.5%with seeds was almost the same as that without seeds,but the IP was significantly decreased by the seeds addition.The result suggested that IP was the nucleusformation process,but the seed addition is not affected by crystal growth.The increase of IP on addition of HPC (Fig.6)might be induced by inhibition of the formation of nuclei by the steric intermolecular effect of HPC and decrease of D v .Therefore,the addition of seed crystals did not affect the crystal growth rate.In other words,HPC strongly inhibited nucleus formation in the crystallization of CBZ.5.ConclusionsThe transformation of CBZ anhydrate was de-pressed dependent on the binder solution concen-tration.The transformation inhibition might be caused by the reduced of nucleus formation on HPC addition.The nature of the bulk powders and excipients,such as the polymorphic form,particle size and distribution,crystallinity etc.,reflect the history of the chemical and physical treatments of the raw materials.Since the phar-maceutical properties of the preparation are changed by the interaction between the formula-tions during the manufacturing process,the phar-maceutical properties could be controlled by regulating of the formula of the excipients.There-fore,to prepare better quality granules it is neces-sary to monitor and control the characteristics of the powder materials,such as bulk and excipient powders.AcknowledgementsThis work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education,Science and Culture,Japan.M.Otsuka et al./Colloids and Surfaces B:Biointerfaces17(2000)145–152 152References[1](a)M.Otsuka,J.Gao,Y.Matsuda,Effect of amount ofadded water during exrusion–spheronization process of pharmaceutical properties of granules,Drug Dev.Ind.Pharm.20(1994)2977–2992.(b)C.W.Woodruff,N.O.Nuessle,Effect of processing variable on particles ob-tained by extrusion–spheronization processing,J.Pharm.Sci.61(1972)787–790.(c)S.Watano,A.Yamamoto,K.Miyanami,Effect of operational variables on the proper-ties of granules prepared by moisture control method in tumblingfluidized bed granulation,Chem.Pharm.Bull.42(1994)133–137.(d)T.Shiraishi,S.Kondo,H.Yuasa, Y.Kanaya,Studies on the granulation process of gran-ules for tableting with high speed mixer.I.Physical properties of granules for tableting,Chem.Pharm.Bull.42(1994)932–936.[2](a)A.E.A.R.Ebian,R.M.A.Moustafa,E.B.Abul-Enin,Nitrofurantoin I.Effect of aging at different relative humidities and higher temperatures on the drug release and the physical properties of tablets,Egypt.J.Pharm.Sci.26(1985)287–300.(b)A.E.A.R.Ebian,H.T.Fikrat, R.M.A.Moustafa, E.B.Abul-Enin,Nitrofurantoin II.Correlation of in vivo bioavailability to in vitro dissolu-tion of nitrofurantoin tablets aged at different relative humidities and elevated temperatures,Egypt.J.Pharm.Sci.27(1986)347–358.(c)FDA Paper,Guideline:Manu-facturing and Controls for INDs and NDAs,Pharm.Tech.Jpn.1(1985)835.[3](a)J.K.Haleblian,Characterization of habits and crystal-liine modification of solids and their pharmaceutical ap-plications,J.Pharm.Sci.64(1975)1269–1288.(b)H.W.Gouda,M.A.Moustafa,H.I.Al-Shora,Effect of storage on nitrofurantoin solid dosage forms,Int.J.Pharm.18 (1984)213.[4](a)H.Po¨lmann,C.Gulde,R.Jahn,S.Pfeifer,Polymor-phie,Teilchengru¨e und Blutspiegelwerte von Carba, azepin,Pharmazie30(1975)709–711.(b)C.Lefebvre,A.M.Guyot-Hermann,M.Draguet-Brughmans,R.Bouche´,Polymorphic transformations of carbamzepine during grinding and compression,Drug Dev.Ind.Pharm.12(1986)11–13.[5]N.Kaneniwa,J.Ichikawa,T.Yamaguchi,K.Hayshi,N.Watari,M.Sumi,Dissolution behavior of carba-mazepine polymorhps,Yakugaku Zasshi107(1987)808–813.[6]P.Kahela,R.Aaltonen,E.Lewing,M.Anttila,E.Krist-offersson,Pharmacokinetics and dissolution of two crys-talline forms of carbamzepine,Int.J.Pharm.14(1983) 103–120.[7]N.Kaneniwa,T.Yamaguchi,N.Watari,M.Otsuka,Hygroscopicity of carbamazepine crystalline powders, Yakugaku Zasshi104(1984)184–190.[8]W.W.L.Young,R.Suryanarayanan,Kinetics of transfor-mation of anhydrous carbamazepine to carbamazepine dihydrate in aqueous suspensions,J.Pharm.Sci.80 (1991)496–500.[9]M.Otsuka,H.Hasegawa,Y.Matsuka,Effect of poly-morphic transformation during the extrusion-granulation process on the pharmaceutical properties of carba-mazepine granules,Chem.Pharm.Bull.45(5)(1997) 894–898.[10]A.Watanabe,S.Suzuki,M.Sugihara,Inhibitory effect ofsodium caseinate on the phenytoin recrystallization, Yakuzaigaku50(1990)179–186.[11]T.Kuroda,Crystal is Living,Saiensu-Sya,Tokyo,Japan,1984.[12]Hand Book of Crystalline Technology,in:M.Yamamoto(Ed.),Kyoritsu Press,Tokyo,Japan,1971..。
盐酸多奈哌齐多晶型及其溶液介导转晶过程的研究
methods usage morphology crystallography polymorphic transition
Thermal gravimetric analysis(TGA) Hot-stage microscopy FT-IR, Raman, solid-state nuclear magnetic resonance(NMR)
2.4 小结 1.通过溶液结晶筛选盐酸多奈哌齐多晶型，发现在一种新的晶型。 2.采用多种表征方法PXRD、DSC、TG、固体红外和水含量分析盐酸多 奈哌齐多晶型结构、稳定性差异。发现盐酸多奈哌齐新晶型含有少量 水，初步估计晶型的稳定性为III晶型〉V晶型〉IV晶型(或II晶型、 新晶型)〉I晶型。
12
பைடு நூலகம்Tianjin University
（三）盐酸多奈哌齐结晶热力学研究
13
Tianjin University
（三）盐酸多奈哌齐结晶热力学研究
3.1 盐酸多奈哌齐新晶型和II晶型溶解度的测定
7 6 5 4 3 2 1 0 280
1(NEW) 11:1(NEW) 7:1(NEW) 3:1(NEW) 1:1(NEW) 1:2(NEW) 1(II) 11:1(II) 7:1(II) 3:1(II) 1:1(II) 1:2(II)
85岁以上人群的患病率为33%,因此 阿尔茨海默病将成为威胁人类的最 严重疾病之一.
3
1.1. 盐酸多奈哌齐性质
盐酸多奈哌齐
分子式:C24H29NO3•HCl
至今专利报道发现，盐
分子量:415.96
化学名:1-苄基-4-[(5,6-二 甲氧基-1-茚酮)-2-亚甲基] 哌啶盐酸 CAS号:120011-70-3
湿法造粒 转晶
湿法造粒转晶全文共四篇示例，供读者参考第一篇示例：湿法造粒转晶技术是一种制药工业中常用的方法，能够将粒状物质转变为结晶状态。
这种技术可以有效地提高药物的稳定性和溶解性，从而提高药效。
本文将介绍湿法造粒转晶技术的原理、流程和应用领域。
一、湿法造粒转晶技术的原理湿法造粒转晶技术是通过溶液中添加结晶助剂，使得原料药物分子重新排列，形成稳定的晶体结构。
在整个过程中，药物被包裹在结晶助剂中，形成颗粒状的晶体团。
这种方法能够有效地提高药物的稳定性和溶解性，使药物更容易吸收，并且降低因药物结晶不完全而引起的制剂变质的风险。
1. 原料筛选：首先需要对原料进行筛选，选择适合湿法造粒转晶的药物。
通常选择那些在固态和液态条件下都有较好的晶体形态和溶解性的药物。
2. 溶液准备：根据所选药物的性质和需求，准备良好的溶剂。
溶剂的选择及浓度的确立对于湿法造粒转晶的成功至关重要。
3. 结晶助剂添加：在溶液中添加结晶助剂，调节药物结晶的速度和形态，帮助药物形成稳定的晶体。
4. 搅拌混合：将药物和结晶助剂充分混合，使其均匀分散在溶液中。
5. 结晶：通过调节温度和搅拌速度等条件，促使药物形成稳定的晶体结构。
6. 分离：将形成的晶体团进行分离，获得细小颗粒状的晶体团。
7. 干燥：将湿法造粒转晶得到的颗粒进行干燥处理，去除水分，得到干燥的晶体颗粒。
8. 包装：将干燥的晶体颗粒进行包装，得到最终的产品。
湿法造粒转晶技术在制药领域有着广泛的应用。
它不仅可以用于提高药物的稳定性和溶解性，还可以用于控制药物的释放速度、改善口感和颜色等方面。
具体应用领域如下：1. 控释制剂：通过湿法造粒转晶技术可以制备出具有缓释性能的药物颗粒，延长药物的作用时间，降低用药频率。
2. 改善口感：一些药物具有较差的口感，通过湿法造粒转晶技术可以使药物颗粒更加均匀和细小，提高口感。
4. 提高溶解性：通过湿法造粒转晶技术可以使药物在体内更容易溶解，提高药效。
第二篇示例：湿法造粒转晶是一种常用的制药工艺，它在药物制备过程中起到了关键作用。
药物晶型转化与控制的研究进展
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化工学报
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引言
多晶型是同一物质生成不同结构的晶体的一种 现象 " 它在有机药物中广泛存在 ( 据统计 "> @] 以 上的医药产品以固体形式存在 " 而且其中大部分是 晶体 ( 美国 药 典 ! # > 版# 片 剂 样 品 中 约 有 " )] 的 药物存在多晶型现象 ( 随着分析技术的发展 " 越来 越多的药物被发现存在多晶型现象 ( 对于多晶型药 物来说 " 同一药物不同晶型的产品可能存在晶体内 部分子间作用力以及表面性质的差异 " 其理化性质 如溶解度 % 熔点 % 密度 % 硬度 % 热容 % 晶体形态等 可能有所差异 " 这 不 仅 会 影 响 医 药 产 品 的 流 动 性 % 可压缩性 % 凝聚性能等加工性能 " 更重要的是还可 能引起药物溶出速率 % 溶出度 % 稳定性等的质量差 异 " 从而影响药物的生物活性与生物利用度 " 导致 临床疗 效 的 差 异 ( 如 抗 溃 疡 药 西 咪 替 丁 存 在 C% V%, 等多种晶型 " 仅 C 型最 有 效 " 而 国 产 西 咪 替 丁一般并 非 完 全 C 晶 型 " 从 而 影 响 了 疗 效 * 另 一 种抗溃疡药法莫替丁有 " 种晶型 " 其熔点 % 红外光 谱 及 理 化 性 质 差 异 明 显" 其 中 V 晶 型 的 活 性 明 显 大于 C 晶 型
添加剂对氯化钠结晶的影响
添加剂对氯化钠结晶的影响
汤秀华
【期刊名称】《化学工业与工程技术》
【年(卷),期】2010(31)2
【摘要】考察了不同添加剂种类、用量及蒸发结晶温度对氯化钠晶体形状、堆密度的影响.实验结果表明,添加剂葡萄糖和山梨醇对氯化钠晶体形状影响较明显.当蒸发温度60 ℃、葡萄糖用量0.15%～0.20%(占氯化钠的质量分数)时,有较多的星型晶体,且产品堆密度比不加添加剂时低;当蒸发温度75 ℃、山梨醇用量(占氯化钠的质量分数)0.05%～0.15%时,氯化钠晶体的形状变化较大,堆密度明显降低,且效果优于添加剂葡萄糖.
【总页数】3页(P15-17)
【作者】汤秀华
【作者单位】四川理工学院,材料与化学工程系,四川,自贡,643000
【正文语种】中文
【中图分类】TS3
【相关文献】
1.结晶添加剂对硫酸钾结晶过程影响研究 [J], 候长军;霍丹群;唐晓萍
2.表面活性剂对氯化钠结晶形态的影响 [J], 黄炳海
3.新型碳化塔重碱结晶动力学及添加剂对结晶影响的… [J], 马淑兰;史季芬
4.盐田饱和卤水的化学成分对氯化钠结晶过程的影响 [J], 张士宾; 丁吉生
5.氯化钠的存在对五水硫酸铜结晶的影响 [J], 马慧斌(译)
因版权原因，仅展示原文概要，查看原文内容请购买。
添加剂对聚氯乙烯结晶行为、微观形态和性能影响的开题报告
添加剂对聚氯乙烯结晶行为、微观形态和性能影响的开题报告一、研究背景Polyvinyl chloride (PVC)是一种重要的工程塑料，具有广泛的应用领域，如建筑、汽车、家具等。
添加剂被广泛用于PVC中，以改善其性能和制造工艺。
然而，添加剂会影响PVC的结晶行为、微观形态和性能，因此对添加剂对PVC的影响进行系统研究具有重要意义。
二、研究目标本文将系统研究以下方面：1. 添加剂对PVC结晶行为的影响。
通过热分析、X射线衍射等手段，探究添加剂对PVC结晶行为的影响。
2. 添加剂对PVC微观形态的影响。
通过扫描电镜、透射电镜等手段，研究添加剂对PVC微观形态的影响。
3. 添加剂对PVC性能的影响。
研究添加剂对PVC力学性能、耐热性等方面的影响。
三、研究方法1. 实验材料选用工业级PVC作为研究对象，选用常用的添加剂如增塑剂、稳定剂。
2. 实验步骤(1) 制备PVC样品。
选取适宜的配方、挤出工艺和模具，制备出PVC试样。
(2) 采用热分析、X射线衍射等手段，研究添加剂对PVC结晶行为的影响。
(3) 采用扫描电镜、透射电镜等手段，研究添加剂对PVC微观形态的影响。
(4) 采用万能材料试验机、热老化箱等设备，研究添加剂对PVC力学性能、耐热性等方面的影响。
四、预期结果本研究将为了解添加剂对PVC的影响提供有力的实验数据，并为PVC材料的制备工艺和应用提供有益的参考。
五、研究意义本研究对PVC材料的结构、性能等方面进行深入研究，有助于深入了解PVC的应用和制备的工艺，并为相关领域的研究提供参考。
同时，也可以为工程科学及材料领域的研究提供一定的理论支撑和实验数据。
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This amino acid is relatively soluble in water (86 g / L at 25°C) and has a net negative charge at pH = 7. The isoelectric point of glutamic acid is at pH 3.22. L-glutamic acid crystallizes easily under moderate conditions, has two known polymorphs and is available in pure [3-form ( > 99%). Industrially, glutamic acid is of great importance in that over 10000 tons are produced annually for use primarily as a food additive and in pharmaceuticals [1,2]. The two polymorpbs of L-glutamic acid have distinctly different crystal habits [3,4] and are known to have different thermodynamic stabilities, as evi-
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C R Y S T A L
GROWTH
ELSEVIER
Journal of Crystal Growth 172 (1997) 486-498
The effect of surfactants on the crystallization and polymorphic transformation of glutamic acid
Amino acids have much higher melting points t similar size because their crystal lattice is held together by strong electrostatic forces between positively and negatively charged functional groups of neighboring molecules as well as the usual hydrogen bonding found in molecular crystal solids. L-glutamic acid consists of a five-carbon backbone, two carboxylic groups, and an amino group.
0022-0248/97/$17.00 Copyright © 1997 Elsevier Science B.V. All rights reserved PII S 0 0 2 2 - 0 2 4 8 ( 9 6 ) 0 0 7 7 1 - 3
N. Garti, H. Zour/Journal of Crystal Growth 172 (1997) 486 498
Abstract
Glutamic acid can crystallize in two polymorphic structures depending on the crystallization regime. The study demonstrates an efficient method to preferentially crystallize the non-stable polymorphic structure (the ~x-form) in the presence of surface active agents. The rate of transformation was found to depend on the rate of growth of 13 and not on the rate of dissolution of ~. The growth rate of 13 was a function of the supersaturation of the solute in solution. It was shown that the transformation could be inhibited by the addition of surfactants. The surfactants are capable of adsorbing preferentially to the or-growing crystals and solution mediating (retarding) the transformation of the c~- to the 13-form. It was suggested that the surfactant nature and steric considerations were important for the inhibition of both nucleation and growth of the 13-polymorph. A Langmuir approach indicated that the kinetic parameter was related to the volume of surfactant adsorbed at the crystal surface. No changes in crystal morphology were observed, indicating that adsorption was not specific to any crystal face. Different mechanisms of surfactant adsorption were suggested: adsorption of single molecules at low concentrations of surfactant and formation of hemimicelles at higher concentrations.
Nissim Garti *, Hadassa Zour
Casali Institute of Applied Chemistry, The Hebrew Unicersity of Jerusalem, Jerusalem 91904, Israel Received 1 June 1996; accepted 1 September 1996
487
denced by differences in their solubilities in aqueous solutions [5,6] and enthalpies (differences in heats of solution) [7]. According to the solubility diagram, at 45°C the solubility of the or-form is 28.5 g / L and the [3-form is 23.0 g / L . The molecules of L-glutamic acid are also conformationally different in each of the two polymorphs. The conformational differences of the glutamic acid molecules may influence the orientation of the functional groups within the crystal lattice of each polymorph. In the [3-form, the carboxylic groups with their negative charges are oriented toward the surface of the crystal whereas the positively charged amine groups lie below the surface and between the carboxylic groups. Molecules in the c~-form are oriented such that the carboxylic groups lie beneath the surface and the amine groups are directed outward and away from the carboxylic groups [8]. These differences are the basis for the different surface properties of the two polymorphs. Much work has been done in understanding the role of the surfactants in the crystallization process of fatty acids and fats. The mechanisms related to their adsorption onto the faces of the growing crystals as well as their effect on the crystal structure modifications and transformation in solution and in the solid state, was elucidated (the button syndrome) [9-11]. The adsorption of surfactants onto the crystal surface can be either surface-specific or non-specific. In the first case, the surfactant molecule will selectively adsorb onto a crystal face (much the same as any other impurity) and retard the growth of the crystal in that direction, effectively changing the crystal habit. The second case is that of non-specific adsorption, where the surfactant adsorbs onto all the surfaces, slowing growth and not necessarily changing the crystal habit. In this case, the Ostwald ripening effect (where small crystals which are thermodynamically unstable dissolve, while larger crystals continue to grow) can be retarded by inhibiting growth and dissolution processes. It has been found that smaller molecules will act on specific crystal surfaces, generally at active sites, whereas larger molecules will be non-specific, acting on all surfaces mainly by sterically hindering the approach of growth units [ 11-19]. Glutamic acid is a small organic molecule which