去除环氧树脂中环氧氯丙烷的方法

Process for removing trace amounts of epichlorohydrin

from heat sensitive glycidyl products

A vertical jacketed column of 0.5 inch (1.27 cm) diameter was packed to a height of 18 inches

(45.72 cm) with fine wire mesh. The column was fitted with a jacket through which temperature controlled polyethylene glycol was circulated to maintain the desired temperature in the column. The column was fitted with a source of vacuum with vacuum gauge and an inlet at the bottom of the column for introducing heated nitrogen as a purging gas. The nitrogen was heated to the temperature of the column by an external heat source, and the rate of flow of nitrogen gas was monitored and controlled by a flowmeter and control valve.

An epoxy resin or product containing glycidyl groups having over 2000 ppm of epichlorohydrin present therein, was placed in a 1000 ml bottom-outlet flask fitted with a thermowatch control mantle attached to the top of the packed column.

The flask and contents were then heated to a temperature sufficient to allow the epoxy resin or product containing glycidyl groups to flow readily, but to a temperature insufficient to cause the thermal decomposition thereof. This temperature was the same as that maintained in the packed column and of the heated nitrogen purging gas. Heated nitrogen purging gas was admitted to the column and a pressure (vacuum) of 410 mm Hg was imposed on the system. The heated epoxy resin or product containing glycidyl groups was allowed to flow into the packed column by gravity feed.

The stripped resin or product was collected at the bottom of the packed column with the flow rate determined by timing the run and weighing the resin or product. The flow rate was adjusted to the desired level by use of a metering valve on the bottom-outlet flask.

The stripped resin or product containing glyc idyl groups was analyzed for epichlorohydrin content to measure the effectiveness of the stripping step. After the analysis was completed, the stripped resin or product containing glycidyl groups was passed through the packed column again for as many times as was needed to reduce the level of epichlorohydrin to less than 10 ppm.

The results of these stripping experiments using four different starting materials showing the number of passes through the column required to reduce the epichlorohydrin levels to less than 10 ppm.