DE804565C - Process for the continuous production of high-boiling dicarboxylic acid esters of 1,4-chlorobutanol - Google Patents

Description

A process for the continuous production of high-boiling dicarboxylic acid ester of 1, 4-Chlorbutanols was gef reasons, that one high-boiling dicarboxylic acid esters of the 4-Chlorl) utanols can be prepared continuously in a very simple manner with excellent yields i, if one of the esterification, at temperatures above the boiling point 1, 4-Chlorbutanols performs in the manner that one I, 4-Chlorbutatiol countercurrent to the counter-current of a continuously passed through the Urnsetzungsgefäß solution of the dicarboxylic acid or its anhydride.

The easiest way to carry out the reaction is to use a tower which can be heated from the outside and which is advantageously provided with packing elements, to add a solution of a dicarboxylic acid, such as succinic acid, adipic acid, phthalic acid or their anhydrides, in the 1,4-chlorobutanol or an inert one used for the esterification organic solvent is allowed to flow from top to bottom, while t, 4-chlorobutanol, which has expediently mixed with an esterification catalyst such as chlorine, hydrogen, sulfuric acid or toluenesulfonic acid, is introduced through a tube inserted into the tower from below. The temperature in the middle of the tube is kept at the esterification temperature, for example at 120 to 170 °, while it is kept somewhat lower at the top and bottom. You can also keep the entire reaction space at the esterification temperature. While at the lower end of the tower the 1, ' ster, in which the not yet reacted starting material e and catalyst can be dissolved, you can remove the water resulting from the reaction and possibly part of the unreacted i at the upper end of the tower , 4-chlorobutanol and by-products such as (, o-üj'-dichlordil) titvläther. distill off. The crude ester is expediently subjected to a fractional distillation in a column, during which the volatile components present in it are driven off and, expediently, worked up together with the distillate driven off at the top of the esterification vessel (, e, vessel, in order to further process the components to utilize.

The parts given in the example below are parts by weight. 13 C is 1) ie 1 By a filled tube with Raschig rings is passed from top to bottom every hour 380 9 of a 4o ll, / o solution of Phthalsäureanhydri d in ruder i. 4-chlorobutanol (containing IJ 6o / o 1, 4-chlorobutanol, 304% TetrahN-drofuran, 8 II / o hydrochloric, 1.6 () / o water), 'as obtained by prolonged standing, a solution of 28.2 Parts of hydrogen chloride in 71.8 parts of tetralivdroftirane (with about 2.2 0/0 water) are obtained. The temperature in the top quarter of the tube is 94 ', i in the second quarter 134' and in the lower half 145-. 500 parts per hour of the crude 1,4-chlorobutanol and 75 parts of hydrogen chloride are passed through a tube pushed axially into the lower end of the tube. At the same time, the crude di (w-chloro) utyl phthalate is drawn off at the lower end through a riser pipe, so that the tower remains filled up to the level of the inlet. The unreacted 1, 4-chlorobutanol is in the tower in tetrahydrofuran and Chloi- converted -asserstoli u%, which together with the I Unisetzungswasser, small amounts of 1, 4-dichlorobutane and where) '- 1) ichlordli) utyläther head distill off the tower.

The crude ester is passed through a vertical, acid-proof column, which is heated from the outside to 1 -30-. At the upper end of the column, the low-boiling fractions distill off, the ester flowing off at the lower end is blown out with steam, freed from unreacted plithalic acid with hot and then dried.

The distillate becomes your reaction urine and that from the column "eininsani fed to a second column, at the top of which was tetrahydrofuran and anhydrous Distill off hydrogen chloride, which can be used for a further reaction. A mixture of 1,4-dichlorobutane, #o -ether is drawn at the lower end of the column and 22% hydrochloric acid, which form two layers and separate from each other \\ - earth.

After 117 hours of reaction, 21,400 parts of tetrahydrofuran are obtained. 17 -loo parts of phthalic anhydride and 13 parts goo chlorine, vasserstoff 38 5oo Plitlialsäuredichlorbutvlester parts, 4 parts 4oo dichlorobutane and 879 parts of 1) ichlordibutvlätlier.

Claims (1)

PATENT APPLICATION: Process for the continuous production of high-boiling Dicarboxylic acid ester of i, 4-chlorobutanol, characterized in that the esterification at temperatures above the boiling point of i, -j-CIilorl) utanol in the way carries out that the latter is continuously countercurrent through the reaction vessel directed dicarbonsätirelösung leads.