Patented Oct. .13, 1925. 1,557,154 ’ UNITED STATES PATENT OFFICE. ' _‘ ANTHONY GEORGE, 0F NIAGARA FALLS, NEW YORK, ASSIGNOR TO THE MAT‘HIESO‘N ALKALI WORKS, INC., 0]? NEW YORK, N. Y., A CORPORATION OF VIRGINIA. MANUEAO'I‘URE BENZO‘YL CHLORIDE. No Drawing. Application '?led July 22, 1924. Serial No. 727,413. T 0 all ‘whom; it may concern: limited to its use. Zinc benzoate, zinc sul Be it known that I, ANTHONY GEORGE, fate, zinc oxide, or zinc oxychloride may also a citizen of Greece (who has declared his be used. ’ ' 55 intention of becoming a citizen of the United With su?iciently effective agitation it is 5 States), residing at Niagara Falls, in the possible to obtain rapid reaction when the county of Niagara, State of New York, have ‘anhydrous catalyst is added directly as a invented certain new: and useful Improve ?nely divided powder. Where agitation is ' ments in the Manufacture of Benzoyl Chlo not effective, however, it'is advantageous to 60 ride; and I do hereby declare the following use a carrier for the catalyst,.for example, 10 to be a full, clear, and exact description of by impregnating pumice, charcoal, asbestos the invention,‘ such as will enable others or other inert material which will ?oat on skilled in the art to which it appertains to the reaction mixture with the catalyst and make and use the same. ' v adding the impre nating material to the 65 This invention relates to an improved benzotrichloride. gl?y using such an inert 15 process for the manufacture of benzoyl carrier, the catalyst is easily brought to the chloride. " T‘ surface of the benzotrichloride ‘and reaction The usual methods for the preparation of starts as soon'as water is added. , . benzoyl chloride involve the use of benzoic It is ‘important for‘ the successful opera To acid, or its salts, and some compound of tion of the process that the water be added 20 sulfur and chlorin. It has also been pro at a regulated rate, not in excess'of that at posed to prepare benzoyl chloride by heating which it will react. If excess water accumu benzoic acid with zinc chloride and adding lates in the reactor, it'will dissolve thecata benzotrichloride. lyst and thereby retard or inhibit the reac 15 According to the present invention, ben tion.‘ The catalyst should remain in the 25 zoyl chloride is produced directly from ben solid or semi-solid state. throughout'the re zotrichloride, in a simple andadvantageous action. \ It is also‘ important that the agita manner by the addition of water in regu tion be su?icient to disperse the water and lated amounts to benzotrichloride in which maintain the catalyst or inert material con 80 is suspended a small amount of a catalyst, taining the catalyst in suspension. 30 particularly anhydrous zinc chloride. I‘ The amount of water which is added is have found that it is possible to go directly regulated‘and any large excess of water is from benzotrichloride to benzoyl chloride avoided. The addition of an excess of water simply by the addition ‘of water in the sense will cause further reaction and the'forma-' of the following equation :—_ - tion of benzoic acid. Some benzoic acid may ‘incidentally be formed during the hydrolysis of the benzotrichloride to form benzoyl chloride, but so long as any benzotrichloride In the process of the present invention, the remains it will react with such incidental benzotrichloride with a small amount of amounts of benzoic acid as may be formed 40 anhydrous zinc chloride suspended therein and give benzoyl chloride. v , is treated with a slight excess of the theo This ‘reaction prevents the formation of retical amount of water indicated by the appreciable amounts of benzoic acid so long above equation. The hydrochloric acid is as any benzotrichloride remains. If, how 95 given off in gaseous form and the benzoyl ever, further additions of water are made 45 chloride and the insoluble zinc chloride re after the benzotrichloride has all been con maining are separated by ?ltration or de Verted into benzoyl chloride‘, formation of cantation. The crude benzoyl chloride can benzoic acid will take place; but such forma~ then be recovered by distillation in ,vacuo, tion in any considerable amount is not de 100 yielding thereby a very pure product. sired in the present process, and the amount 50 I have found that Zinc chloride is a par of water, added is so regulated that substan ticularly advantageous catalyst in the pres— tially the maximum yield of benzoyl chloride ent process, but the present invention is not will be obtained. 1,057,154 The proper amount of water to be added directly dependent upon the rate at which is dependent‘upon the benzotrichloride con the water is added. The acid evolved con tent of the chlorinated toluene used. Benzo tains only traces of organic impurities, and trichloride is commonly produced by the may be absorbed in water according to any chlorination of ' toluene, and, depending of the well-known methods. The tempera 70 upon the method'of chlorination, varying' ture is maintained at 100 to 110° C. through contents of the benzotrichloride may be out the reaction. ‘contained in the chlorinated product. If After _61 to 64 lbs. of water have been the toluene has been chlorinated in the added the reaction mass is digested at about 10 light at a'temperature' of 100 to 150° C. and 100-120° C. for half an hour with contin 75 has a speci?c gravity of 1.375 to 1.385, it ued agitation. The reaction may then be may, for purposes of calculating theproperl. considered complete. ' ' amount of water to use, be assumed to con The contents of the reactor are then‘ tain from 85 to 90% of benzotrichlori-de. vIt drawn off, ?ltered in an acid proof ?lter to 15 has been found advantageous to use about 5 remove the zinc chloride, and introduced 80 to 10% above the theoretical amount of into a stoneware vacuum still, and the prod water ‘in order to insure a high quality prod uct subjected to vacuum distillation, for ex~ uct. If more water is used, the quality of ample, by carrying out the vacuum distilla the product may be improved, but the yield tion at 110 to 120° C. under about 45 mm. will be‘ somewhat reduced due to the forma pressure. A yield of about 75 to 85% or 85 tion of benzoic acid. If too little water is more of benzoyl chloride is obtained, which used the yield will ‘be increased but uncon in the case of the particular example under verted'chlorinated products will usually be consideration amounts to around 370 lbs. obtained in the product. Withv chlorinated The residue remaining in the still after 25 toluene of the character referred to above, the vacuum distillation vis then digested with 90 and using from 5 to 10% excess water, milk of lime and treated for the recovery yields of as high as 75 to 85% or higher can of pure benzoic acid, for example, by steam be obtained of vacuum distilled benzoyl distilling the small amount of benzaldehyde chloride melting at —1 to +2° C. After and oils that may be present, and ?ltering 30 the benzoyl chloride has been removed from off the solution of calcium- benzoate, andfre 95 the residue by vacuum distillation, the resi covering the benzoic acid from the calcium -due contains some benzoic acid and some benzoate by acidi?cation, ?ltration and benzoyl chloride. This residue may be washing. - . treated for the recovery of the benzoic acid The zinc chloride and pumice ?ltered off 35 and benzoyl chloride by suitable methods, as at the end of the ‘hydrolysis may be em 100 for instance, by digesting the residue with ployed again if desired as catalyst in the milk of lime, steam distillin the small ' further carrying out of the process. amount of benzaldehydeand OllS that may There may be some reduction in yield due be present, and ?ltering off the solution of to charring during the vacuum distillation 40 calcium benzoate. Pure benzoic acid can be of the benzoyl chloride, but this is usually 105 obtained "from the solution by acidi?cation, not more than a fewv percent at most. High ?ltration and washing. temperatures during distillation, however, The invention will be further illustrated increase the amount lost in this manner. by the following speci?cdescription but it The benzoyl chloride produced in accord 45 will be understood that theinvention is not ance with the above example melts at —1 110 limited thereto: . to —-2° (3., has a.speci?c gravity of about 750 lbs. of chlorinated toluene, chlori nated, for example, as above described, and 1.213 M72101 and contains around 24.8 to of speci?c-gravity 1.38 at 20° C. are placed 26.0% of chlorine, thus indicating a product 50 in a 100 gal. stoneware vessel provided with of high purity. ' 115V an agitator and capable of bein heated. ‘A It will thus be seen that the process of‘the re?ux condenser is not require . With the invention provides an improved method for agitator in operation, the temperature is the manufacture of benzoyl chloride directly raised to about 100° C. and pumice impreg from benzotrichloride, in which the benzo 65 nated with zinc chloride is added in such trichloride is subjected to a partial and reg- 120 amount that about 5 lbs. of zinc chloride are ulated hydrolysis'with water in the presence introduced. _ ' of a catalyst, particularly zinc chloride, and Water is thenrun in slowly at a rate not that the benzoyl chloride can be readily ob in excess of that at which it will react, and tained in a state of high purity from the 60 the addition of water is continued until reaction product.