GB195117A - Improvements in process of producing high grade esters - Google Patents

Abstract

195,117. Marks, E. C. R., (U.S. Industrial Alcohol Co.). Nov. 11, 1921. Esters, for example ethyl acetate, are prepared continuously by introducing a preheated mixture of alcohol, organic acid, and catalyst into a column still heated by direct steam, rectifying the ester produced to obtain a constant-boiling mixture of ester, alcohol and water, which is then mixed with water, separating the resulting two layers, containing high and low percentages respectively of ester, and finally rectifying the former. The production of ethyl acetate from alcohol, vinegar and sulphuric acid is described. These materials are fed by separate pipes into the mixing tanks 1, 2 designed for alternate use, and the mixture pimped thence to a supply tank 10, from which it is fed through the combined preheater and dephlegmator 13 and trapped valved pipe 19 to a column still 20 provided with direct steam 21, with the ordinary pans, overflow pipes, and vapour caps, and with an overflow pipe 25 and return vapour pipe 27 for the sulphuric acid waste. The vapours pass by the pipe 17 to the dephlegmator 13, whence any condensate is returned to the still 20, and subsequently to a warm condenser 31, the vapour from which passes to a cold condenser 41 with a final vapour vent 49. The condensates from both condensers pass by a trapped valved pipe 39 to a rectifier 53 similar to the still 20 but having a closed steam heater 54. A pipe 51 conveys back to the still 20 any liquid in excess of that with which the subsequent apparatus is capable of dealing and the trapped pipe 29 with return vapour pipe 62 returns alcohol of 70-90 per cent strength to the still. The vapours from the rectifier pass to a dephlegmator 64 and condenser 72 arranged so that the condensate from the dephlagmator returns to the rectifier and the condensate, i.e. the constant-boiling mixture from the condenser, passes by a pipe 81, with return pipe 82 for any excess liquid, to a measuring receptacle 84 in which the inlet pipe 81 is joined to a container 86 for distributing the liquid laterally at the periphery of the receptacle 84. A pipe 87 surrounds the inlet pipe, is slotted at 88 and carries a scale 89 to indicate the head under which the liquid flows into 87. A similar arrangement 92 serves to measure out the required volume of water fe'd thereto by a pipe 93. Mixing takes place in the coil 90 and the separation into two layers in the chamber 96. The lower layer containing a small percentage of ester is fed back by a trapped pipe 59 to the rectifier 53, while the upper layer passes to a rectifier 99 with dephlegmator 101 and condenser 111. The condensate from the former is carried back to the rectifier 99 while that from the latter passes by the pipe 118 either to be mixed with water through the pipe 85 if it contains more than 80 per cent ester, or back to the rectifier 53 if it contains less. The pipe 119 is a safety-device for use if the rectifier 53 is temporarily out of operation. The ester is tapped off from the bottom of the rectifier 99 by a pipe 123, with return vapour pipe 122, to a cooler 125 and storage receptacle 129. Butyric acid, methyl alcohol and hydrochloric acid as catalyst are also mentioned as initial materials. Specification 195,118 is referred to.