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Patented Feb. 1, 1938 ‘ ~ ~ * > .. 2,107,264? UNITED STATES PATENT OFFICE 2,107,264 PROCESS FOR THE PRODUCTKON OF CAR BON DISULPHIDE John Philip Baxter, Widnes, and Leslie James Burrage, Liverpool, England, assignors to Im perial Chemical Industries Limited, a corpo ration of Great Britain No Drawing. Application February 10, 1937, Se rial No. 125,156. In Great Britain January 3, 1936 9 Claims. This invention relates to an improved process for the manufacture of carbon disulphide. The usual process for the manufacture of car bon disulphide involves the reaction between ele mental sulphur and carbon. On a commercial scale this reaction is generally effected at tem peratures in the neighborhood of 900° to 1000° C., the sulphur in the form of vapor being passed through a bed of the glowing carbon. Many pro 10 posals have been made as to the type of carbon which may be used. For instance, it has been suggested that brown coal, anthracite and coke can be used in the process. Wood charcoal of selected qualities is the only form of carbon 15 which has been employed to any extent in com mercial practice. This invention has for an object the prepara tion of carbon bisulphide. A further object is the preparation of carbon bisulphide from a 20 cheap and readily available source of carbon. _ A still further object is the preparation of carbon bisulphide of a good quality in commercial quan tities. A still further object is a general advance of the art. Other objects will appear herein 25 after. These objects are accomplished by the follow ing invention wherein sulphur in vapor form is passed through a bed of glowing carbon which has been prepared by carbonizing coal at a tem 30 perature between about 500° C. andabout 600° C. The carbon" material may be reacted with sulphur immediately after the carbonization treatment or any time after. In the preferred embodiment of the invention the carbonized coal 35 is subjected to a‘heat treatment at an elevated temperature in the substantial absence of air for a few hours and subsequently reacted with sul phur vapors. The present invention is based on the observa 40 tion that by the carbonization of coal at tem peratures of the order of 500° to 600° C., a form of carbon is obtained suitable for reaction with sulphur vapor in the manufacture of carbon di sulphide. This is surprising in view of the lack 45 of success in the working of the prior proposals on a commercial scale. At the same time, care must be taken in the selection of the coal for carbonization. The various properties which are to be taken into consideration in this connection 50 include ash content, carbon content, and leaking properties. In connection with the ash content it is pref erable, though not absolutely essential, that the material be of low ash content in order that 55 possible mechanical di?‘lculties may be avoided (C1. 23-206) in carrying out the reaction. Therefore, it is preferred that the coal before carbonization should be of low ash content. The carbon con tent of the initial coal is not critical but prefer ably it should be of low rank. That is to say, the carbon content should be relatively low in the neighborhood of 80% to 82% calculated on the dry ashless basis. At the same time com paratively good results may be obtained when using material from the carbonization of coal of '10 somewhat higher and somewhat lower carbon content. On the other hand, it is essential that the coal submitted to the carbonization process must not be readily fusible, it must be non-cak ing and probably should contain a high propor tion of vitrain. The conditions under which the carbonization is conducted must be carefully controlled, in order that the material produced may be suit able for successful large scale operation. This 20 latter point is strikingly illustrated by trials which have been carried out on batches of washed coals. Average lots of a number of coals of the type above speci?ed were carbonized at tem peratures of 400°, 500°, 600° and 700° C., for periods of 1, 1.5, 3 and 5 hours in each case. Each lot of coke obtained from these carbonization runs was examined separately, when it was ob served that only the cokes produced at tempera tures of 500° and 600° C. were suitable for car- ‘ bon disulphide manufacture commercially. Even with these materials there were differences which were apparently dependent on the duration of carbonization. Thus the cokes resulting from the treatments carried out for 1, 1.5. and 3 hours reacted at rates which were substantially the same as those observed with wood charcoal nor~ mally used, whereas carbonization for a period of 5 hours gave a material distinctly less reac tive. With regard to the other temperatures we 40 found that the use of 400° C. was ine?ective for the production of a suitable coke, while the ma terial formed at a temperature of ‘700° C. was distinctly less reactive than those produced at a temperature between about 500° C. and. about 45 600° C. This temperature range appears to be quite critical for the production of a suitable form of coal carbon for the reaction with sulphur, as We have found that a variation of much above 20° C. on either side furnishes a product which 50 is markedly inferior. Carbon produced .in the manner described above is, when examined visually, characteris tically different from coal carbon produced by normal coking processes and which is unsuitable 2,107,264 2. for carbon disulphide manufacture. Whereas an unreactive coke has a silvery-grey appearance, the material used according to the present inven tion is quite black. Although not conclusive, this property enables a preliminary estimate to be made of the suitability’ of coal carbon for the reaction. Another property by which the car bon may be evaluated for the sulphur reaction is the rate at which it reacts with oxygen. Suit able carbons burn rapidly when heated in a flame limited to the specific embodiments thereof ex cept as defined in the appended claims. We claim: 1. The process for the production of carbon disulphide by reacting carbon and sulphur in’ known manner, characterized by the fact that the carbon used has been obtained by carbon? izing coal between the temperatures of approxi mately 500° C. and approximately 600° C., for a 10 period of 1 to 3 hours. 2. The process according to claim 1 further in air as compared with a slow burning rate of . characterized by the fact that the carbon sub unreactive carbons. sequent to the carbonization and prior to the re The reaction between the carbon and the sul phur for the production of carbon disulphide is action with sulphur has been submitted to a heat treatment'in the neighborhood of 700° C. 15 carried out in the normal manner, for example, by charging the carbon into a vertical retort and passing‘sulphur'vapor through the glowing mass while maintaining a temperature of about 900° to 1000° C. 20 ' It is» possible to use directly in this reaction the carbon produced by the carbonization of coal at 500° to 600° C. without any intermediate treatment. We ?nd, however, that such carbon contains an appreciable content of combined hydrogen, a large proportion of which reacts with sulphur to form hydrogen sulphide during the manufacture of the carbon disulphide. This ob viously reduces the efficiency of the process and in any case increases the equipment necessary for the treatment of the effluent gas from the process. Accordingly, we ?nd it desirable to submit the coal carbon to a heat treatment shortly before it is passed into the carbon di sulphide retort. This heat treatment may be carried out in the substantial absence of air in any convenient form of apparatus and con; sists merely in heating the carbon to about 600° C. to about 800° C., and maintaining this temper-' ature for some hours. In this heat treatment 40 some lowering of the’ reactivity takes place, but this is more than offset by theresulting gain in the general e?iciency of the carbon disulphide production. At the same time, however, it is necessary to avoid the use of temperatures ma 45 terially higher than the above. If too high tem peratures are used, the rate of the reaction be tween the sulphur and the carbon becomes too low for e?icient commercial production. From a study of the above speci?cation, the 50 advantages of the above invention will be read ily apparent. The chief advantage of the in vention lies in the fact that an initial raw ma terial which is inexpensive compared with wood charcoal becomesrreadily available for the pro 55 duction of carbon disulphide. Other advantages reside in the fact that carbon disulphide may be easily prepared in commercial quantities and in high quality. ' As many apparently widely different embodi 60 ments of this invention may be .made without departing from the spirit and scope thereof, it is to be understood that this invention is not to be 3. The process for the manufacture of carbon disulphide which comprises carbonizing a non caking coal preferably of low ash content and relatively low carbon content at a temperature of approximately 500° to 600° C., for a period 20 of 1 to 3 hours, and reacting the carbon thus obtained with sulphur. 4. The process according to claim 3 in which the carbon is submitted to a heat ‘treatment sub sequent ‘to a carbonization process and prior to 25 the reaction with sulphur. ' 5. The process of preparing carbon disulphide which comprises passing sulphur vapors over a bed of carbon material which has been pre pared by carbonizing ‘coal at a temperature be 30 tween about 500° C.>and about 600° C., for a periodof 1 to 3 hours. 7 q 6. The process of preparing carbon disulphide which comprises carbonizing coal at a'tempera ture between about 500°C. and about'600° C. for‘ a period of 1 to 3 hours, and then passing sul phur vapors over a bed .of such material main tained at an elevated temperature. 7. The process of preparing carbon disulphide which comprises carbonizing coal of low ash 40 content and low carbon content at a temperature between about 500° C. and about 600° C. for a periodof 1 to 3 hours, heating the carbonized product to a temperature of about 600° to 800° C., and then passing sulphur vapors over theheat treated product which is maintained at an ele vated temperature. . r 8. The process according to claim 7 wherein the heat treated product is maintained at a tem~ perature of about 900° to 1000° C. ‘ - 50: > 9. The process of preparing carbon disulphide which comprises carbonizing coal of low ash content and having a carbon content of about 80 to 82% calculated on the dry ashless basis at a temperature between about 500°‘to 600° C. for a 5.5 period of from 1 to .3 hours, heating the carbon ized product to a temperature of about 600° C. to 800° C. and then passing sulphur vapors over the heat treated product which is maintained at a temperature of about 900° to 1000° C. JOHN PHILIP BAXTER. ' . LESLIE JAMES BURRAGE.