i Patented‘ Aug. 11,‘ 1936 V 2.050.442 _

UNITED STATES‘. PATENT OFFICE ‘

2,050,442 _ monomer. or ETHYL Anconor. Floyd 1. Metsger, New York, N. Y., assignor to Air Reduction Company, Inc., New York, N. ‘2., REISSUED ‘ a corporation of New York No Drawing. Application June 21,1931, Serial No; 547,452 14 Claims. (01. 260-158) This invention relates‘ to the production of or into contact with the acid catalyst at a high ethyl alcohol from ethylene. temperature, condensing the alcohol and excess It is known that ethyl alcohol can be manu steam while maintaining the high pressure, and factured from ethylene by absorbing the ethylene 7 recycling the ethylene with suitable further ad ~ 5 in strong sulfuric acid to form ethyl hydrogen ditions of ethylene and steam in the further car- 5 sulfate or diethyl sulfate, diluting with water to rying out of the process. , . hydrolyze the ethyl sulfate, distilling the resulting The catalyst which I have found particularly ethyl alcohol from the diluted mixture and re valuable is a sulfuric acid catalyst which is a much concentrating the dilute acid for further use in weaker sulfuric acid than the strong acid here 10 the process. This process involves a series of tofore commercially used in the manufacture of ill separate and successive operations carried out in ethyl alcohol. The sulfuric acid employed may diii'erentapparatus. The reconcentration of the have a strength, for example, of from 15 to 70% dilute acid is a major expense of the process. The of sulfuric acid. Apparently the ethylene com formation of ethyl alcohol in this way is usually blnes to a considerable extent with the acid to 15 accompanied by the‘ formation of a considerable form ethyl sulfate, so that the catalyst is a mix- 15 amount of ether with corresponding reduction in ture of sulfuric acid and an ethyl sulfate. The the amount of alcohol produced. strength of the acid catalyst is maintained sub The present invention provides an improved stantially constant at the high temperatures and method for the manufacture of ethyl alcohol, pressures employed by using regulated propor 20 which enables the objections above mentioned to tions of ethylene and steam in the gaseous mix- 24;) be largely overcome and minimized, which elim ture passed through or into intimate contact with inates the necessity of using strong sulfuric acid the acid catalyst. and of reconcentrating dilute acid, which enables The temperatures employed in the present the production of the alcohol to be accomplished process will vary with the strength of the acid N :1 without any considerable formation of ether,‘ catalyst, the pressure and the ratio of steam to as which can be carried out in a continuous manner, ethylene employed, but in general the tempera and which has other advantages, such as those tures are much higher than it is possible to em- ' hereinafter set forth. ' ploy with the same strength of acid at atmos~ According to the process of the present inven pheric pressure. By passing the mixture of 30 tion the alcohol is produced continuously by pass steam and ethylene in contact with the sulfuric so ing the ethylene, in admixture with suitable acid catalyst under a high pressure it is possible proportions of steam, into intimate contact with to use a'much higher temperature without in an acid catalyst, and particularly a sulfuric acid creasing the concentration of the acid and even catalyst, while maintaining the catalyst at a high with a much more dilute acid as compared with. 35 temperature and maintaining the gases under a operations at atmospheric pressure. Using a sul- 35 high pressure, with resulting conversion of the furic acid catalyst, without promoters, and with ethylene into alcohol, which is subsequently con mixtures'of steam and ethylene, the temperatures dcnsed along with the excess steam from the es are in general in excess of about 170° C. and for caping gases; - best results I have found a temperature consid 40 I have found that'ethyl alcohol can readily be erably in excess of 200° to be advantageous, e. g., to produced in a continuous manner by passing a around 235 to 250° C. The temperature, however, mixture of ethylene and steam, in suitable pro cannot be varied independently of the other portions, into intimate contact, with a relatively conditions because the temperature, pressure, dilute sulfuric acid catalyst at a regulated high acid strength and ratio of steam and ethylene '45 temperature and pressure, with resulting forma are interdependent. With the same acid strength 45 tion of a gaseous mixture containing the alco and the same ratio of steam and ethylene the hcl together with the excess of ethylene and temperature can be very considerably increased steam, from which the alcohol and steam can be by carrying out the process under a high pres readily condensed. . sure, and the increased temperature seems to 50 I have further found that this conversion of have the effect of greatly increasing the activity 50 ethylene into-‘ethyl alcohol can advantageously be of the acid catalyst and promoting the formation carried out in a cyclic manner by maintaining a of alcohol. I circulating stream of ethylene under a high'pres The pressures employed in the present process' sure, admixing therewith‘ steam in suitable pro- are in general in excess of 100 pounds, and much 55 portions, passing the resulting mixture through higher pressures are more advantageous, such as 55

0 2 ’ 9,050,442 pressures above 200 pounds, and more particularly of steam and ethylene ‘can also be prepared by pressures around 600 pounds or higher. with passing the ethylene through a body of water the higher pressures, for example, around 600 maintained at a sufl‘iciently high temperature and pounds, or even much higher pressures, there under the same pressure employed in the con 6 should be a proper correlation of the strength of verter. In this case the recirculating ethylene can 5 the acid catalyst, the temperature and the pro be passed through such a boiler containing water portion of steam and ethylene. With such high . and the temperature of the boiler maintained to pressures it is possible to use temperatures much I give the proper proportion of steam and higher than it is possible to use at atmospheric ethylene in the gases passing therefrom to the l0 pressure with a sulfuric acid'catalyst and at the - converter. 10 same time to maintain a much lower strength of Instead of carrying out the process in a cyclic acid catalyst. The combined use of a high tem manner, by passing the mixture of steam and perature and pressure with a relatively dilute acid ethylene through a single converter, then through catalyst makes it possible to produce ethyl alcohol a condenser, and then recirculating the ethylene 15 in commercial quantities without the objection with admixture of steam under the same high 15 able decomposition which would take place at the pressure to the same converter, two or more con higher temperatures and with stronger acids at verters can be employed in series with or without atmospheric pressure. condensation of the alcohol and steam from the The proportions of steam and ethylene can be gases escaping from the first converter, then 20 varied but in general for the production of alco-. admixing additional steam or ethylene or both 20 hol free or relatively free from ether I have found if desired, and passing the gases through the sec it advantageous to use an excess of steam over ond converter, etc., and in such case the con that theoretically required for combining with densers as well as the‘ converters are advan the ethylene for example, the ratio of one and tageously maintained under a high pressure so 25 one-half parts of steam to one of ethylene or of that condensation as well as conversion may take 25 two of steam to one of ethylene or even a higher place under such pressure. ratio of steam to ethylene, e. g., four or more The use of a series of converters makes possible parts of steam to one of ethylene. the maintenance of di?erent strengths of acid I have also found it possible to produce ether catalyst and of diiferent temperature and pres 30 as well as alcohol, where that is desired, by using sure conditions in the different converters, there- 30 a lower ratio of steam to ethylene or a stronger by making it possible for example to produce acid or a lower pressure; but in general the ethyl alcohol free or relatively free from ether strength of the acid catalyst will depend upon the in one converter and a mixture of alcohol and ratio of steam to ethylene and the conditions of vether in another converter where this is desired. 35 temperature and pressure employed. When a Instead of using a sulfuric acid catalyst, other 35 ., .aconstant mixture of steam and ethylene is passed acid catalysts can be employed, for example, a through or in intimate contact with the acid phosphoric acid catalyst, or a mixture of phos catalyst under a high temperature and pressure, phoric and sulfuric acids. In referring to the the strength of the acid catalyst will reach an acid catalyst I use the term to include the acid 40 equilibrium and will thereafter remain at the catalyst with whatever other constituents such 40 equilibrium strength as long as the conditions of as alkyl sulfates it may contain during the cata the process, 1. e., the temperature, pressure and lytic conversion. Provision should be made for ratio of steam to ethylene remain constant; but insuring intimate contact of the gases with the the equilibrium reached will represent a much acid catalyst, such as the dissemination or dis 45 more dilute acid than that which would represent tribution of the gases throughout the acid cata- 45 the equilibrium at the same temperature and at lyst. Where the converter contains a consider atmospheric pressure. ' able body of acid the distribution of the gas and The ethylene employed in the process may be the intimate .contact of the gas and acid can be obtained from any suitable source, such as by promoted by suitable ?lling‘ material which im 50 liquefaction and recti?cation of the gases pro pedes the upward ?ow of the gases through the 50 duced from oil or gas cracking operations. Pure acid. The filling material should of course be or relatively pure ethylene can readily be pro of suitable acid-resistance material. Instead of duced and when produced or available can be used using a liquid body of the acid catalyst, with in the process. Instead of using the pure ethylene, passage of’ the gases into intimate contact there 55 the impure hydrocarbon can be used admixed with, the acids may be absorbed on suitable car- 65 with other gases or'vapors which are not objec riers such as pumice stone, silica gel, etc. tionable in the process, such as saturated hydro The action of the acid catalyst can be pro’ carbon vapors which are not changed during the mated by the addition thereto of certain pro process, or other inert gases or vapors. moters, or of certain substances which form or 60 Where the ethylene, employed in the process is become promoters during the carrying out of 60 impure, it will be evident that the extent to which this process. Silver or silver sulfate may be it can be recycled, when the process is carried out added in small amount as such a promoter, and with recycling, will be limited by the building up of the use of such a promoter enables the process impurities or of inert gases or vapors or by the to be carried out at somewhat lower tempera ()5 formation of undesirable reaction products there tures, or with somewhat increased yields, than 66 from, in which case the gas after one or more when promoters are not present. Lithium sul ' passages through the converter should not be fate may also be added with bene?cial results. further cycled or should be purified or a constant The apparatus employed in carrying out the discharge of the recycling gases should be ef process includes a converter or converter cham 70“ fected to maintain the recycling gases of sum ber containing the acid catalyst and provided 70 cient purity. ' with means,such as a filling material distributed The steam employed in the process can be sup throughout the acid, for bringing the mixture of plied from any suitable source, such as a high , ethylene and steam into intimate contact there pressure steam boiler, and admixed with the with while maintaining the catalyst and the 75 ethylene in regulated proportions. The mixture gases under the necessary pressure and at the 75 . 2,050,442 . ' '\~ 3 necessary high temperature, together with means on discontinuation of the process and on cooling for supplying the steam and ethylene in suitable the apparatus and removing the catalyst from proportions and under the necessary high pres - the converter showed an acid strength of about sure, and a condenser for condensing the alcohol 41% sulfuric acid and a small content of ethyl and admixed steam from the escaping gases. sulfate. 5/ That part of the apparatus which comes in com With lower ratios of steam to ethylene or with tact with the acid catalyst should of course be lower pressures (and higher acid strength of the made of suitable acid resistant material, re catalyst I have found that ether is produced sistant to the action of the acid catalyst at the simultaneously with alcohol. ' For example, with 10 high temperatures employed. . about one part of steam to two parts of ethylene 10 Where the process is carried out in a cyclic and at a temperature of about 170° C. and a manner the condenser as well as the converter is pressure of about 200 pounds and a sulfuric acid maintained under a high pressure and the un catalyst in equilibrium with such temperature, converted ethylene is recycled, additional ethyl pressure and ratio of steam to ethylene, the 15 ‘ene admixed therewith, and steam also admixed amount of ether produced was about equal to. 15 therewith so that provision is made for supply the amount of alcohol produced or somewhat ing both steam and additional ethylene to, the greater. At a pressure of about 200 pounds and cycle under the necessary high pressure. The a temperature of about 210° C. and a- ratio of condenser for condensing the alcohol or alcohol‘ about one and one-half parts of steam to one of and ether may be a multi-stage condenser, with ethylene the amount of ether was only about 20 the separate sections or condensers ‘maintained one-half that of the alcohol. Withtemperatures at progressively lower temperatures so that, for up to around 225° C. at .200 pounds pressure and example, the ethyl alcohol is largely condensed with a ratio of four parts of steam to one of ' in the ?rst condenser in the form of a solution ethylene‘ the alcohol produced was practically of alcohol in water, and the ether is largely sepa free from ether. In general the increase in the 25 rated in a subsequent condenser maintained at amount of steam tends to reduce the amount of a lower temperature. Where other is formed ether formed and by using a sufficient amount of along with alcohol it is not necessary to condense steam and suitable'conditions of temperature, out the ether, particularly where it is formed pressure and strength of acid catalyst, the alcohol 30 only in small amounts, but the other can be produced will be free or practically free from 30 recirculated, along with the ethylene, and again ether. The proportion of alcohol to ether may passed through the converter, with maintenance be varied also by varying the time of contact be of the condenser at a temperature that will con tween the vapors and the catalyst. dense the alcohol more or less completely with It is important to avoid too low'a ratio of steam out condensing any considerable amount of with too high a temperature since such» condi- 35 ether. The recycled ether will be subjected to tions tend to give decomposition products of an the action of the catalyst and, by its presence, objectionable character. may retard the further formation of ether, or As distinguished from prior art processes in may itself be hydrolyzed by the steam and cata which ethylene is absorbed in strong sulfuric lyst and converted into alcohol. 1 -. acid followed by dilution to effect hydrolysis and 4" In general, the stronger acid catalysts will be distillation of the alcohol and reconcentration of employed at a lower pressure and temperature the acid for further absorption of the ethylene, and the weaker acid catalysts at a higher pres the present process makes use of dilute acid, that sure and temperature. For example, with- acid is, more dilute than the strong acids required in catalysts of around 65 to 70% acid the pressure such prior processes. The acids employed are 4;, may be around 100 pounds and the temperature. non-volatile inorganic acids which, under the which will vary somewhat with the ratio of steam high pressures used in the process can be heated to ethylene, may be around 170° C. With a sul to a. su?iciently high temperature to exert the furic acid catalyst of around 40 to 45% acid, desired catalytic e?ect continuously upon the - 50 higher pressures around 600 pounds and higher water vapor and ethylene passed continuously 50 temperatures around 250° C. are advantageous. into contact therewith, while maintaining the. The nature of the invention will be further acids as dilute acids of substantially uniform illustrated by the following speci?c examples, strength throughout the carrying out of the proc but it will be understood that the invention is ess when uniform conditions of temperature, Ca LI not limited thereto. pressure and ratio of steam and ethylene, are 55 Ethylene and steam in the proportions of one maintained. a part by volume of ethylene to two parts by vol It will thus be seen that the present process , ume of steam '(measured at atmospheric pres eliminates the use of strongsulfuric acid which sure) were passed through a sulfuric acid cata- has heretofore been used in the production of lyst maintained at a temperature of about 250° C. alcohol from ethylene; that the present process 6“ and at a pressure of about 600 pounds gauge. eliminates the need of dilution of the strong acid The vlume of ethylene passed through the cata solution of the ethylene and distillation of the lyst was about 90 cubic feet ,per hour (measured alcohol from the diluted mixture; and that the at atmospheric pressure) per liter of acid cata present process eliminates entirely the need of lyst and there was obtained a conversion of reconcentrating dilute acid'which is required in m, about 10% of the ethylene into alcohol with such prior processes. little or no ether formed. The alcohol was con It will also be seen that the present process is a densed in the form of a solution containing continuous process in which the strength of the around 10 or 14% of alcohol by volume, the acid catalyst, once established, remains constant, alcohol yield being about one-half liter per hour ' in which a high pressure of the gases is main- 7U of absolute alcohol per liter of acid catalyst em tained as ‘well as a high temperature during the ployed. The strength of the acid catalyst was catalytic conversion, and that a relatively high the equilibrium strength under the conditions ratio of steam to ethylene is employed with a of‘ temperature and pressure and ratio of steam relatively dilute acid catalyst, under conditions to ethylene employed. The acid catalyst tested coordinated as to temperature, pressure, ratio of '75 4 action: steam and ethylene and strength of acid catalyst of ethylene into intimate contact with a sulfuric so that the alcohol can be continuously produced acid catalyst, the acid having a strength ma under uniform conditions which can be main ‘terially less than 70%,‘ at a temperature of tainedfor long periods of time. around 250° C. and a pressure of around 600 I claim: pounds per square inch or higher and condensing 5 1. The method of producing ethyl alcohol in a the alcohol from the resulting gases. continuous manner which comprises passing a 8. The process of producing ethyl alcohol in a mixture of ethylene and water vapor in regulated continuous manner which comprises passing a proportions under a high pressure, in excess of mixture of ethylene and water vapor, the water 10 100 pounds per square inch, into intimate con vapor being in excess of the ethylene, into inti 10 tact with a dilute non-volatile inorganic acid cat mate contact with a sulfuric acid catalyst of from alyst maintained at an effective and substantially 15 to 45% sulfuric acid maintained at a tempera uniform catalytic strength and temperature, the ture around 250° C. and at a pressure exceeding temperature being in excess of about 170° C. and about 600 pounds per square inch, cooling the 16 cooling the resulting gases to condense the alco resulting gases to condense alcohol therefrom, hol therefrom. admixing additional water vapor with the re 2. The method of producing ethyl alcohol in a maining ethylene and admixing additional ethyl continuous manner which comprises passing a ene to make up for that converted into alcohol, mixture of ethylene and water vapor in regulated and recirculating the resulting admixed ethylene proportions under a high pressure, in excess of and water vapor in contact with the acid catalyst, 20 100 pounds per square inch, into intimate con the ethylene being maintained as a circulating tact with a dilute sulfuric acid catalyst of from stream of ethylene at approximately the same 15 to 70% sulfuric acid and at a temperature in high pressure while passing in contact with the excess of 200° C. to effect continuous formation acid catalyst and during subsequent cooling and of ethyl alcohol, and cooling the resulting gases further admixture of steam and ethylene there 25 to condense the alcohol therefrom. with. 3. The method of producing ethyl alcohol in a 9. The ‘process of producing both ethyl alcohol continuous manner which comprises passing a and ether in a continuous manner which com mixture of ethylene and water vapor in regulated prises passlng a mixture of ethylene and water proportions, with the water vapor in excess of the vapor in regulated proportions, and with the ethylene, under a high pressure, in excess of 100 ethylene in excess of the water vapor, and under - pounds per square inch, into intimate contact a high pressure in excess of 100 pounds per square with a dilute non-volatile inorganic acid catalyst inch into intimate contact with a dilute sulfuric containing a promoter, said acid catalyst being acid catalyst maintained at an effective and sub maintained at an effective and substantially uni stantially uniform catalytic strength and tem— 35 form catalytic strength and temperature, the perature for the production of both alcohol and temperature being in excess of 170° C. and cooling ether, the acid being of a strength of from 15 the resulting gases to condense the alcohol there to 70% and the temperature being in excess of from. ' 170° C., and cooling the resulting gases to con 40 4. The method of producing ethyl alcohol in a dense the alcohol and ether therefrom. 40 continuous manner which comprises passing a . 10. The method of producing substantially mixture of ethylene and water vapor in regulated ether-free ethyl alcohol in a continuous manner proportions under a high pressure, in excess of which comprises passing a mixture of ethylene 100 pounds per square inch into intimate contact and water vapor with the water vapor materially 45 with a dilute sulfuric acid catalyst containing - in excess of the ethylene into intimate contact about 15 to ‘70% sulfuric acid and a promoter, with a dilute sulfuric acid catalyst maintained at said catalyst being maintained at an effective a substantially uniform catalytic strength within and substantially uniform catalytic strength and the range of 15 to 70% sulfuric acid and at a. temperature, the temperature being in excess of substantially uniform temperature in excess of 50 170° C. and cooling the resulting gases to con 200° C. and under a high pressure in excess of . dense the alcohol therefrom. 200 pounds per square inch and with regulation 5. The process of producing ethyl alcohol in a of the temperature, pressure, acid strength and continuous manner from ethylene which com excess of steam over ethylene to effect conversion prises passing a mixture of ethylene and water of ethylene into ethyl alcohol substantially free vapor, with the water vapor in excess of ethylene from admixed ether and cooling the resulting into intimate contact with a sulfuric acid catalyst gases in a continuous manner to condense al of less than 70% strength under a pressure in cohol therefrom. excess of about 100 pounds to the square inch ll. The method of producing substantially and at a temperature in excess of 200° C. su?lcient ether-free ethyl alcohol in a continuous manner 60 to maintain the strength of the acid catalyst, and which comprises passing a mixture of ethylene condensing alcohol from the resulting gas. _ and water vapor with the water vapor in excess 6. The process of producing ethyl alcohol in‘a of the ethylene into intimate contact with a dilute continuous manner from ethylene which com sulfuric acid catalyst containing in excess of ' prises passing a mixture of ethylene and water about 15% sulfuric acid but not more than about vapor, the water vapor being in excess of the 45% sulfuric acid at a temperature in excess of 65 amount of ethylene, in intimate contact with the about 235° C. and under a high pressure in excess sulfuric acid catalyst, the acid having a strength of about 600 pounds per square inch and with materially less than 70%, under a pressure in regulation of the temperature, pressure, ratio of excess of about 200 pounds to the square inch and steam to ethylene and acid strength to effect 70 at a temperature of around 200 to 270° C. and conversion of ethylene to ethyl alcohol substan 70 condensing the alcohol from the resulting gases. tially free from admixed ether, and cooling the 7. The process of producing ethyl alcohol in a resulting gases to condense aqueous alcohol continuous manner from ethylene which com therefrom. prises passing a mixture of about one and one 12. The method of producing ethyl alcohol in a 75 half to two parts of water vapor and one part continuous manner which comprises passing a 5 mixture of ethylene and water vapor under a of about 60 to about 70% strength and main pressure in excess of 100 pounds per square inch, tained at a temperature of about 170° C. and re into intimate contact with a dilute- non-volatile moving alcohol from the resulting vapors. inorganic acid catalyst maintained at an effec 14.‘ The method of. producing ethyl alcohol in a tive and substantially uniform catalytic strength continuous manner which comprises passing a 5 and temperature, the temperature being about mixture or ethylene and water vapor under a 170° C. and removing alcohol from the resulting pressure in excess of 100 pounds per square inch, vapors. ' ‘ t into intimate contact with a sulfuric acid catalyst 13. The method of producing ethyl alcohol in a of about 60 to about 70% strength and main continuous manner which comprises passing a tained at s. temperature oi? about 170° C. and 10 mixture of ethylene and water vapor under a removing alcohol from the resulting vapors said pressure in excess of its pounds per square inch, catalyst containing silver sulfate as a promoter. into intimate contact with a sulfuric acid catalyst . FLOYD J. METZGER.