IL50070A - Process for the production of 1,1,2,3-tetrachloropropene - Google Patents

Description

PROCESS FOR THE PRODUCTION OF She present invention relates to a novel for the production of This compound is an important intermediate in the production of and more particularly in the production of certain herbicides for the control of noxious weeds in various crops0 such herbicides there may be mentioned diisopropyl thiol The present patent application has been divided out from our copending patent application is pr a stream comprising to a liqu chlorinating the feed stream that from about 20 to about βθ percent weight of the effluent remains unreacted passing the chlorinator effluent which comprises and to a fractionating fractionating said chlorinator effluent into a a a and a heavy ends recycling the 1 2 fraction to the and removing the on and then in high yield and with jevels of waste the process passing the from the actiona to a caustic dehydroc passing which comprises and tric to a second adding chlorine to the bond of the compounds contained in the dehydrochlo passing the second chlorinator effluent which comprises and opropane to a second caustic passing the fraction from the ractionating column to the second caustic dehydrochlorinator the second chlorinator effluent and the and entachloroprcpanes fraction from the fractionating passing the second tor which and j5 etr to an packed with granules h ving olar the to by heating the in contact h the siliceous to a temperature In the the based upon trichloropropane the chlorinator substitutes for hydrogen by the free radical met od to form more highly propane s Formation of ma initiated by exposing the contents of the to actinic light or by conducting the in contact tic amount of a adical catalyst such as one of the benzoyl urea tertiary butyl or other formers as axobis e chlorination methods arc well known to the skilled and the particular method employed is not a part the it is critical that the of t on of the feed stream be so that from about to about 60 by weight of the feed as in order to limit the number of chlorinated products It is preferred to chlorinate that from about 30 to about percent by of the feed stream remains and more preferred to chlorinate that from to about percent by weight of the feed stream remains Control of the chlorination within the stated limits gives an effluent comprised of the following compounds with ss Boiling Point Centigrate tetra 3 1croprop The compounds are readily separated into 5 in conventional fractionating The may be of any suitable design and may utilize trays or packing to make the necessary Since corrosion is a a packed column is While the type of fractionating column is it is that the five of the following compone separated in order to obtain high yields of the Fraction 1 2 Fraction 3 and a Fraction 5 c loropropane in the This entire stream recycled to Fraction 2 provides the which is the raw material for the preparatio of Fraction 3 is as to a caustic chlorinator which converts the tetrachloropropane to a mixtur of trichloropropenes The design of this deh drochlorinator the of den the of caustic are conventional and not critical clehydrochlorination the effluent which consist essentially of conventional means adds chlorine the double bond to form and The effluent this second chlorinator is then passed to a second caustic The handling of Fraction is another key feature of the Although the methods employed are admittedly the result is Fraction 3 as it passes from the fractionator is a useless by removin HC1 and then adding t useless is converted to valuable precursor for This conversion is important in obtaining the high yield of product from the present Fraction 4 is also passed to the Fraction and the second chlo enter the second caustic dehydrochlorinator as streams or as a single combined The method of operation of this dehydrochlorinator is not cri to the invention and may be the same as or different from the Fraction waste It may be sent directly to waste disposal or utilized for other The or utilization of Fraction 5 is not critical to the present The effluent from the second caustic normally consists essentially of product propene and This stream is passed to an isomerizer which converts totally the oropropene to This isomerization is a particularly unique feature of the The isomerizer is a vessel of any suitable design packed with siliceous granules having a polar The size and shape of the granules will vary depending on the particular operating conditions desired for Factors to be considered in determining granule size and shape are basically process design considerations known to the skilled process such as pressure drop across the vessel process flow tolerable packing silica compounds which may be used in this process include a variety of calcined and clays such kac inite and other salts of silica such as wollastonite cristobalite spodumene and siliceous substances such as silica fumed fibrous aluminum silicate and It is preferred that the granules be clay and more preferred that the granules be The isomerizer operates at a temperature o a out to about preferably from about to about The isomerization is usually carried out at atmospheric The may be carried out a closed vessel or under It is particularly preferred to carry out the zation under reflux at atmospheric Under the stated conditions the second caustic ochlorinator effluent is to a stream consisting essentially of in from about to about 2 preferably from about to about hours and more preferably from about to about 1 The effluent from the isomerizer may be as in the preparation of dilsopropylthiolcerbamate or further purified for use in said preparation or EXAMPLE This example illustrates the chlorination step in the process of preparing and Chlorination of grams of propane is carried out in an open vessel exposed to light from a 5 inch quartz short wave Angstrom suspended immediately above the surface of the The vessel is heated from about 40 to about and about 355 grams of chlorine is bubbled through the at a rate of from about to about 1 per Upon completion of the chierine the of the mass is chromatographic anal and found to be about as ollows tetrachloroprepane 259 and 38 The procedure of except noted is followed to give a about of ane of it ion percent by ic 1 ne heavy ends 6 3 AND 4 illustrate ch lorinations outside the process of this these less percent of the remains as un results in excessive number chlorinated j in heavy The procedure Example as noted is followed to give ehlorinator effluent as mule 3 4 of loropropane I chlorine 99 11 Temperature ehlorinator luent Example 3 Composition by pane G 19 8 1 ne and y E 5 illustrates the of The effluent of Example 1 a pressure of from about 25 to about millimeters of in 2 20 fraction removed and charged to a equipped with an agitator and heated to of sodium hydroxide s dissolved in of s solution to s d fraction over about 2 The mass stirred for 2 hours at about 93 It is determined about the feed the of mast about Thereupon about 2 of sodium h in 2 of water and a quantity of agent mass is heated at a out for an onal The then steam u til the vapor temperature distillate forms t The layers are and the organic layer found to abou and to by Weight 22 9 mixed trichloroprop nes are over molecula and About E MPLE 6 This example illustrates the addition of chlorine the double bond of such as those prepared in Example The mixed of Example 5 are charged to a suitable open vessel and heal to about 55 The contents are exposed to light from a 5 inch quartz short wave lamp Angstrom suspended immediately above the of chlorine are bubbled through the contents at a rate of about to 1 per About of and pentachloropropanes are This as l a the chlorination of Example 1 be carried out with equal facility in the presence of a catalytic amount of or forming When using such a catalyst the presence of light is not This example the dehydrochlcrination mixed and The of and o tained in Example 6 are charged to a suitable vessel equipped with an agitator and heated to about 95 About of sodium hydroxide are added to and dissolved in about of solution is added to for about 2 hours and then steam distilled until the temperature is The distillate forms The layers are separated and the organic layer is found to weigh about to Percent by EXAMPLE This example illustrates the isomerization of to The grams of mixed tetrachloropropenes of Example are charged to a suitable vessel equipped with v reflux tetrachloropropenes is added about grams of about 20 to 40 mesh of attapulgus this addition the clay is previously with mixed tetrac loroprop nes but not dried in order to simulate continuous plant operation and minimize yield loss by adsorption the The mass is refluxed at atmospheric pressure for about 40 minutes and the clay removed by Analysis shows about percent by weight yield of While this has been described respect to certain it is to be understood that it is net so limited and that variations and thereof obviou to those skilled in the art to which this invention appertains can be made without departing from spirit or insufficientOCRQuality

Claims (1)

1. WHAT IS CLAIMED IS 1 A process for prepari ng 2 oropropene wh i ch compri ses feeding a stream to a chlorinating eed stream so about 20 5 about 60 percent by of the ef remains as passing the chlorinator effluent to a fractionating fractionating said effluent into a a tetrachloropropane a a and oropropanes f and 35 a and ends recycling the to the removing the the fraction 20 from the fractionating column to a caustic dehydrochlorinating the passing the dehydrochlorinator effluent comprises mixed trichloropropenes to a 25 adding chlorine o the double of the trichloropropenes contained in the passing the and propanes fraction from the fractionating to the second caustic the second chlorinator effluent and the and from fractionating passing the second effluent which mixed tetrachloropropen s to an isome with having a polar and isome izing to by heating second dehydrochlorinator in contact with the siliceous granules to of from about to about for from about to about 2 The process of Claim wherein the chlorina are carried out i the presence of The process of wherein the are carried out in the presence of a forming The process of wherein id catalyst The process of 1 wherein d feed is chlorinated so that from about 30 to about 50 percent of the chlorinator effluent remains as process of wherein are granules of The process of Claim wherein the clay is v8 The process of wherein t second dehydrochlorlnator effluent is under reflux The process of Claim wherein the dehydrochlorlnator is re luxed for from about to about hou insufficientOCRQuality