新编化学化工专业英语翻译

新编化学化工专业英语翻译题目第二课有机化学专业应用化学(材料化学方向) 院系化学与化学工程学院时间2011.2.18Lesson 2 Organic ChemistryThe nature of Organic Chemistry has changed greatly since 1828. Before that time the scientific philosophy known as “Vitalism”maintained that Organic Chemistry was the chemistry of living systems. It maintained that organic compounds could only be produced within living matter while inorganic compounds were synthesized from non-living matter. Even the word “organic” comes from the same root as the word “organism”or “organ”. However people like Professor Wohler beginning in 1828 determined that it was indeed possible to synthesize organic compounds from those compounds that were considered inorganic. One of the first organic compounds synthesized from basically inorganic compounds was the compound Urea which is a metabolic product of urine. It was synthesized from Ammonium Cyanate considered a compound produced outside of living matter and therefore considered inorganic. Since then many millions of Organic compounds have been synthesized “in vitro” in other words outside living tissue.1 Structural formulasThe building block of structural organic chemistry is the tetravalent carbon atom. With few exceptions, carbon compounds can be formulated with four covalent bonds to each carbon,regardless of whether the combination is with carbon or some other element. The two-electron bond, which is illustrated by the carbon-hydrogen bonds in methane or ethane and the carbon-carbon bond in ethane, is called a single bond. In these and many related substances, each carbon is attached to four other atoms:There exist, however, compounds such as ethene (ethylene), C2H4, in which two electrons from each of the carbon atoms are mutually shared, thereby producing two two-electron bonds, an arrangement which is called a double bond. Each carbon in ethene is attached to only three other atoms:Similarly, in ethyne (acetylene), C2H2, three electrons from each carbon atom are mutually shared, producing three two-electron bonds, called a triple bond, in which each carbon is attached to only two other atoms:By convention, a single straight line connecting the atomic symbols is used to represent a single (two-electron) bond, two such lines to represent a double (four-electron) bond, and three lines atriple (six-electron) bond. Representations of compounds by these symbols are called structural formulas; some examples areTo save space and time in the representation of organic structures, it is common practice to use “condensed formulas”in which the bonds are not shown explicitly. In using condensed formulas, normal atomic valences are understood throughout. Examples of condensed formulas areAnother type of abbreviation that often is used, particularly for ring compounds, dispenses with the symbols for carbon and hydrogen atoms and leaves only the lines in a structural formula. For instance, cyclopentane, C5H10, often is represented as a regular pentagon in which it is understood that each apex represents a carbon atom with the requisite number of hydrogens to satisfy the tetravalence of carbon:2 Organic nomenclatureOrganic nomenclature is the system established for naming and grouping organic compounds.Formally, rules established by the International Union of Pure and Applied Chemistry (known as IUPAC nomenclature) are authoritative for the names of organic compounds, but in practice, a number of simply-applied rules can allow one to use and understand the names of many organic compounds.For many compounds, naming can begin by determining the name of the parent hydrocarbon and by identifying any functional groups in the molecule that distinguish it from the parent hydrocarbon. The numbering of the parent alkane is used, as modified, if necessary, by application of the Cahn-Ingold-Prelog priority(CIP priority) rules in the case that ambiguity remains after consideration of the structure of the parent hydrocarbon alone. The name of the parent hydrocarbon is modified by the application of the highest-priority functional group suffix, with the remaining functional groups indicated by numbered prefixes, appearing in the name in alphabetical order from first to last.In many cases, lack of rigor in applying all such nomenclature rules still yields a name that is intelligible-the aim, of course, being to avoid any ambiguity in terms of what substance is being discussed.For instance, strict application of CIP priority to the naming of the compound-NH2CH2CH2OH would render the name as 2-aminoethanol,which is preferred. However, the name 2-hydroxyethanamine unambiguously refers to the same compound.How the name was constructed:(1)There are two carbons in the main chain; this gives the root name “eth”.(2)Since the carbons are singly-bonded, the suffix begins with “an”.(3)The two functional groups are an alcohol (OH) and an amine (NH2). The alcohol has the higher atomic number, and takes priority over the amine. The suffix for an alcohol ends in “ol”, so that the suffix is “anol”.(4)The amine group is not on the carbon with the OH (the #1 carbon), but one carbon over (the #2 carbon); therefore we indicate its presence with the prefix “2-amino”.(5)Putting together the prefix, the root and the suffix, we get “2-aminoethanol”.There is also an older naming system for organic compounds known as common nomenclature , which is often used for simple, well-known compounds, and also for complex compounds whose IUPAC names are too complex for everyday use.Simplified molecular input line entry specification (SMILES)strings are commonly used to describe organic compounds, and as such are a form of“naming”them.3 Functional groupsFunctional groups are groups of atoms that confer similar properties onto otherwise dissimilar molecules. Carbon, nitrogen, oxygen, hydrogen, and phosphorus are a few of the elements involved in forming functional groups. Carbon can make four bonds. Nitrogen makes three, oxygen two, and hydrogen one.译文：第二课有机化学自从1828年以来，有机化学的性质发生了很大变化。