US1341423A - Process for making sulfur chlorid - Google Patents

Description

R. E GEGENHEIMER AND M MMHANQ PROCESS FOR MAKING SULFUR CHLQRHJu APPLICATION FIIED DEC.28,1918.

Emma May25, 192w,

INVENTORS B! mwm ATTORNEY RALPH E. GEGENHEIMER AND MAX MAURAN, 0F NIAGARA FALLS, NEW YORK, ASSIGNORS TO THE MATI-IIESON ALKALI WORKS (INC.), OF PROVIDENCE, RHODE ISLAND, CORPORATION OIE VIRGINIA.

PROCESS FOR MAKING SULFUR CHLORID.

1,34MAL23.

Specification of Letters Patent.

Application filed December 2a, 1918. $eria1 no. 268,602.

ful Improvements in Processes for Making Sulfur Chlorid, o f which the following is a specification.

This invention relates to the production of the monoand di-chlorids of sulfur, or either of them as desired, and has for its principal object the effecting of this production in a simple and more efficient manner than, to the best of our knowledge, has been i I i exothermic one; but mbeginning the operapossible hitherto.

We have also aimed to produce the desired product preferably continuously and, when desired, in a particularly pure state; the contamination of the so called monochlorid, S GI by the presence therein of the d1 clilorid of sulfur, being substantially el1m1- 'nated, if pure monochlorid be the product sought. These and other objects of our invention will be hereinafter referred to and the novel combinations of steps 111 the process and of means and'elements in the apparatus through the intermediacy of which said process may be effected, will be more particularly pointed out in the claims appended hereto.

In the accompanying drawing, wh1ch forms a part hereof, we have exempllfied a preferred arrangement of such apparatus; but as we are aware of various changes and modifications which may be made herein and in the mode of eifectuating our novel process, without departing from the spirit of our invention, we desire to be limited only by the scope of saidclaims, broadly interpreted in the light of our disclosure.

Referring to said drawlng, in which like reference characters designate like parts in the respective views:

Figure 1 is a diagrammatic representation of an apparatus in and by means of whlch, substantially pure sulfur chlorid may be efficiently and continuously produced.

Fig. 2 is a detail section of a part of said apparatus, taken on the hne IIII of Fig. 1; fragments only of the steam heated, melt ing pan grids being shown, for convenience of illustration.

As shown in said figures, dry chlorin said grid, onto the lower one.

gas, either pure, or as is commercially practicable and cheaper, mixed with air in the proportion of, say, 90 per cent. of chlorin to 10 per cent. of air,--is supplied by the plpe 1 tothe annular header or distributer 2.

A' series of pipes 3 depend from the dis tributer or ring casting 2, into the still 4; the chlorin emerging from said pipes, pref- Patentedll Iay 25;, 192@. I

erably, well down within :a sulfur containing bath '5. In the preferred construction, a series of plugs 6 are provided in the distributer,'to permit of a rod being thrust down therethrough in the event of any of pipes f3 becoming plugged.

The reaction effectedin the still 4 is an which is a valve 11, to control the flow of H molten sulfur out of the melting pan 12. In the latter are two steam heated grids, formed of pipes, 13 and 14; the upper grid having more space between its pipes than the lower,-to allow the smaller pieces of sulfur, initially introduced intothe pan, or produced by the melting down of the larger lumps reposing upon grid 13, to fall through The lower grid lei: is preferably maintained partly or wholly immersed in the layer of molten su-lfur 15, in the bottom of the pan, and sulfur may be flowed into the bottom of the still, as needed, by opening the valve 11. To prevent the sulfur from congealing in this valve or in its pipe.10,I prefer to cover such parts with heat insulating material 16, such as asbestos, magnesia, or the like. The still is provided with suitable means, such as the float controlled indicator 17, for determin' ing the level of the bath; as, desirably, this is maintained well below the top of the water jacket.

More or less mingled with the charge of molten sulfur in the still, is a quantity of sulfur chlorid, or in some cases a mixture of sulfur Chlorids; the purpose of which will be hereinafter explained. This s lfur chlorid is preferably introduced initi llv;

layer of this material present; since, during the course of the operation, sulfur will dissolve in the liquid sulfur chlorid, while some sulfur (especially at the higher temperatures indicated, which yield as a product 'Inonochlorid of sulfur containing free sulfur dissolved therein) will distil out of the bath and,depending upon the temperatures employed,will condense, more or less,

in the upper part of the still, and fall back into the bath, to redissolve or re-distil when its temperature again rises. This action will proceed substantially continuously, and hence, normally, no line of demarcation between the sulfur and the sulfur chlorid will exist.

Surrounding the still above the steam jacket and extending up, preferably above the level of bath 5, is a water jacket 18, the flow of water through which is controlled by the valve 19in the water inlet pipe; the wastewater passing out via pipe 20.

Aconduit 21 conveys the gaseous reaction products, normally continuously evolved during the operation, together with any air present, up to the inclined header 22, which in turn delivers to the condenser 23. This is preferably of the water-cooled, surface type; water being introduced through the pipe 24 and passing out by Way of pipe 25, whereby to cool the coil 23.

The condensed sulfur chlorid is deposited. in the storage tank 26, and is drawn off,-

from time to time or continuously, as desired, by means ofthe pipe 27 and its valve 28.

At the left hand end of the tank, as viewed in Fig. 1, is a connection 29 leading up to a reflux condenser 30. The coil 30 in this condenser may be water or brine cooled; pipe 31 and 32 respectively permitting ingress and egress of the cooling fluid.

If the chlorin introduced into the system throughpipe 1, were pure, or, in other words, free from air, this reflux condenser would not be necessary; but since the chlorin supplynormally contains from 5 to 10 per cent. of air onaccount of the cost of pure chlorin, We prefer to provide the condenser 30, to trap any vapors which might, be swept from the storage tank along with the air. The colder that this reflux condenser is maintained, the lower will be the partial pressure of sulfur chlorid in the exit mixture, and hence the less will be the loss of sulfur chlorid From the condenser 30, the gases pass via pipe 33, to a scrubber 34, which may be of any design. Preferably it comprises a tank filled with caustic soda or milk of lime; the pipe leading from the reflux condenser, passing down into the liquor and the escaping gases bubbling up through the latter to cause any remaining sulfur chlorin vapor to be trapped. Only pure air therefore passes to the suction pump 35 which is connected to the scrubber and maintains a partial vacuum in the whole system.

If the chlorin supplied through pipe 1 were under pressure, pump 35 would, of course be unnecessary; but we prefer to operate thesystem under a partial vacuum, especially whenusing chlorin admixed with air, because such operation is less objectionable if leaks, by any accident, happen to develop in the apparatus; while, further, a smaller pump can be used than when operating the system under pressure. 0n the other hand, pressure has its advantages, since with the system under pressure the partial pressure of sulfur chlorid vapor in the mixture is less than with the system under partial vacuum and therefore less care need be ex ercised in preventing loss of S CL.

As proper control of the temperature of the exothermically reacting charge and gaseous product or products in the still, is es sential, we provide a thermometer 36 in the still head; said thermometer being preferably disposed as shown.

At the bottom of the still is a valve 37; the purpose of which will be hereinafter mentioned.

The operation of the system and mode of conducting the process may now be briefly described.

Let us assume that molten sulfur has been introduced into the still from the melting pan, preferably until the lower ends of the pipes 3 are immersed therein; this sulfur being covered by a mass of sulfur chlorid, previously introduced, or sulfur chlorid and sulfur residually present from the pre vious operation of said still.

v At such time steam will, of course, be flowing through the jacket 7, to maintain the sulfur bath molten.

A dry mixture of, say, 92 per cent. chlorin and 8 per cent. air is then flowed through the conduit 1 and thence down through the As soon as the exothermic reaction is well under way, the steam valve 8 is closed and the temperature of the still is thereafter controlled by regulating the flow and temperature of the water admitted to the water jacket past valve 19. k

This temperature control is most important and the combination thereof with the provision of a bath into which the current, or preferably currents, of chlorin are directed, for intimate contact, first with that portion of the bath most rich in sulfur and the temperature of the gases passing off from the still aids in the maintenance of proper reaction conditions within the still, with the result that when we wish to produce "sulfur" monochlorid alone, we obtain this product continuously and free from excess of chlorin and sulfur; instead of having to be content with the delivery to the condenser of a mixture of sulfur chlorids.

Indeed, in all other methods with which we are acquainted, the sulfur chlorid, especially in continuous processes, is either produced 'mixed with the dichlorid; or the monochlorid is supercharged with sulfur and then trickled down through towers, or the like, and chlorinated to the desired degree.

In no case,'he retofore, has it been possible to effect chlorination of the sulfur, exactly to sulfur monochlorid, on but a single pass of the liquor through a single piece of apparatus.

This, we'believe is rendered possible by h a and due 1n very large measure to the tem-' perature control; since some action is still going on in the sulfur chlorid vapors from the time that said vapors leave the level of the bath 5 in the still, almost to the time that they reach the point where the thermometcr 36 is located.

The novel bath 5, of the described constitution, is important, because we have observed that when the chlorin is delivered through pipes 3, for exampleyto a bath of sulfur alone, very little chlorid is formed; the bulk of the gas passing off from the still, remaining chlorin.

T'Vhile a chlorid containing bath might be allowed to gradually build up, such an operation would, of course, be tedious and mits of the withdrawal of any residue that may accumulate, due to the use of sulfur containing slight impurities.

The product formed is condensed in the surface condenser 23 and collects in the tank 26, from which it may be withdrawn through pipe 27. Substantially all uncondensed chlorid is condensed in the reflux condenser, so that, normally, but mere traces remain to be collected in the scrubber 34.

By means of the just described apparatus, the process may be effectuated to produce either pure monochlorid of sulfur or any desired mixture of sulfur monochlorid and sulfur, or of the monochlorid and dichlorid; this change in product being effected by varying the following factors:

1.-Depth of sulfurIS Cl in the still.

2.-Rate of flow of chlorin.

3.Regulation of temperature. by vary ing the rate of flow and temperature of water supplied to the jacket 18 of the still.

For example; To obtain pure sulfur monochlorid, S CI one may proceed as described in the foregoing, maintaining the depth of S+S Cl in the still equal to from about one half to three quarters of the total depth of the still, and varying the rate of flow of the incoming chlorin gas while at the same time controlling the temperature until the temperature in the still head, indicated by the thermometer 36, is 138% To obtain mixtures containing the monochlorid substantially free from, the diehlorid but containing any specified amount of dissolved sulfur (such mixtures being desired by the rubber trade), we shut off the cool-J ing water, wholly or in part, as needed, and, if necessary, insulate the still, in order that the heat of the reaction may cause distillation of sulfur along with the sulfur chlorid; determining at the still head .by, in effect, calibrating the thermometer 36,-what temperature at that point will give the particular composition of distillate desired. Thus, for example, a product containing- 5% dissolved sulfur was obtained in the apparatus given by way of illustration, when the temperature of the vapor in the upper end of pipe 31, was allowed to reach 225 C.

If the dichlorid be desired, practically any specific mixture may be obtained by decreasing the depth of S}-S. ,Cl in the still, or by increasing the rate of flow of the in-" coming chlorin, or both; while maintaining the cooling water conditions such that the temperature at the still head corresponds to that which, in an apparatus of given dimensions and with a given depth of bath in its still and a given rate of flow of chlorin thereinto, will yield the particular mixture of monochlorid and dichlorid, desired. These rates for any given product of particular consistency, will, of course, depend upon the size of apparatus employed, etc; but may, obviously, be readily determined by those skilled in the art, in view of the disclosure herein.

In conclusion, we desire to particularly emphasize the fact that while chlorin gas acts comparatively slowly upon a bath of molten sulfur alone,if S cl be present in said bath, some of the sulfur dissolves there- 'in and this dissolved sulfur then reacts very rapidly with the chlorin bubbling up therethrough.

As the reaction proceeds, the temperature of the molten sulfur is raised .by the heat of the exothermic reaction, beyond the boiling point of-sulfur monochlorid, so that subsequent reactions may take place between sulfur chlorid vapor, sulfur vapor and chlorin,partly while these gaseous substances are bubbling up through the molten mass, and partly inthe vapor filled space above the sulfur containing bath and below the condenser. Furthermore, it should be noted, as a marked economy of operation, that the heat evolved by this exothermic reaction is the heat which permits us to distil off the desired product.

Having thus what we claim is: 1. The process of making monochlorid of sulfur which comprises, treating with free chlorin a deep bath comprising a chlorid of sulfur in contact with molten sulfur, to effect an exothermic reaction in said bath,

described our invention,

and regulating the temperature of said bath and of the gaseous reaction products emerging therefrom, to cause the sulfur bearing constituent of said products to consist substantially solely of sulfur monochlorid.

2. The process of making a chlorid of sulfur which comprises, treating with free chlorin a bath comprising monochlorid of sulfur having sulfur dissolved therein, by injecting gaseous chlorin into said bath and allowing the reaction gases to then bubble up through said bath, cooling said bath to remove a part of the heat developed by said reaction, collecting the vapors which escape from said bath, regulating the tem perature of said vapors to produce the product sought, and condensing said product. I

3. ,The process of making monochlorid of sulfur which comprises, injecting a mixture of air and chlorin into a bath containing sulfur dissolved in sulfur monochlorid, collecting the gaseous reaction products and regulating the temperature thereof to cause the chlorin bearing constituent of said products to exist substantially solely as the mono- -chlorid of sulfur by the time that they have traversed a determined distance from said bath, and then condensing the so produced monochlorid and separating the air therefrom.

at. The process of making monochlorid of sulfur which comprises producing said monochlorid in the gaseous phase, substantially free from sulfur dichlorid, by efi'ecting but a single passage of gaseous material, which includes free chlorin, through a sulfur supplying bath, to combine said chlorin and sulfur by an exothermic reaction, and removing heat from said bath and from the gaseous reaction product escaping therefrom through a conduit, to an extent sufficient to maintain the temperature of said product at about 140 C. at a point in said conduit relatively adjacent said bath but sufliciently distant therefrom to permit ofthe stabilization of said product.

5. The process of making monochlorid of sulfur which comprises establishing a flow of material in the gaseous phase through a closed system in substantially all parts of which a partial vacuum is maintained, said gaseous material initially containing free chlorin, reacting upon said free chlorin to combine sulfur therewith, converting any dichlorid of sulfur formed during the course of said reaction, to the monochlorid of sulfur by temperature regulation while a part at least of said dichlorid is in the gaseous phase, and separating said monochlorid of.

sulfur from the remainder of said gaseous material by converting said monochlorid to the liquid phase thereof.

6. The process of making monochlorid of sulfur which comprises injecting gaseous chlorin-into a bath containing both a chlorid of sulfur and free sulfur, to effect an exothermic reaction by combining said sulfur and chlorin, while utilizing the heaKe'volved by said reaction, to vaporize the chlorin bearing products of said reaction and also some of said sulfur, and reacting upon said vaporized products with said vaporized sul-- fur to form the product sought.

7. The process of making a chlorid of sulfur which comprises treating with gaseous chlorin, a chlorid of sulfur in which is dissolved free sulfur, to exothermically combine said chlorin and sulfur, while utilizing the heat evolved by the exothermic reaction, to vaporize the product of said reaction and regulating the temperature of the so' formed vapor to control the content of said desired chlorid of sulfur therein.

8. The process of making monochlorid of sulfur which comprises forming said monochlorid by combining free chlorin and free sulfur in the presence of liquid sulfur chlorid, while controlling the temperature of the reaction to practically at once yield the product sought substantially free from sulfur dichlorid, said temperature being maintained in excess of 130 C.

9. The process of making monochlor-id of sulfur which comprises substantially uninterruptedly forming said monochlorid by bubbling a gaseous current comprising free chlorin continuously up through a bath containing free sulfur dissolved in liquid sulfur chlorid, Wh1le controlling the temperature of the reaction to continuously yield

Images