Патент USA US2407815код для вставки
Patented Sept. 17, 1946 2,407,814 UNITED STATES PATENT OFFICE ' 2,407,814 CATALYSTS Harry A. Cheney, Oakland, Calif., assignor to Shell Development Company, San Francisco,‘ Calif., a corporation of Delaware No Drawing. ‘ Application June 21, 1943, Serial No. 491,724 ‘ 5 Claims. (01. 252-251) 1 2 and hexylene, respectively, materials highly de This invention relates to the manufacture of supported catalysts and relates more particularly to the manufacture of catalysts} comprising at sirable as starting materials in the production of such products as synthetic rubber and aviation least one metal of group VIII in combination fuels, renders these catalysts exceedingly valu able, Of these catalysts those comprising cobalt with activated carbon which have been found to be particularly effective in the conversion of ole ?nic hydrocarbons to the lower boiling of-the and/ or nickel in combination with activated car bon are particularly outstanding‘in their ability to effect this desirable polymerization reaction. Catalysts comprising cobalt are somewhat-pre employed also in other types of hydrocarbon con 10 ferred over those comprising nickel since they versions. , enable the conversion of ‘the ole?nic hydrocar Catalysts comprising elements of group VIII hop to the lower boiling of the linear‘ polymers find application in a wide variety of processes, thereof at temperatures below 250° C.‘ and pref particularly those involving the conversion of erably not substantially in excess of 150° 0., hydrocarbons such as, for example, hydrogena whereas those comprising‘ nickel ‘generally ‘re tion, polymerization, dehydrogenation, “isomeri; quire somewhat‘higher temperatures, for exam; zation, gas pyrolysis, aromatization, etc; These ple, up to about 350° 0., to attain equivalent metals in a limited number of cases are used per se in relatively large fragments, pieces or chunks. Methods heretofore generally employed in the’ Most catalytic processes, however, require‘their usage in dispersed or ?nely-divided form depos~ 20 preparation of these catalysts comprise‘tihe im pregnation of the carrier material with a solu-‘ ited upon suitable support‘ materials. Support tion of ‘a compound of an element of group‘ VIII ' materials which may be employed, comprise ma linear polymers thereof, although they can be results. ' ‘ " ’ ‘ ‘ and subsequently heating the resulting mixture‘ terials of porous structure such as activated car at atmospheric pressure to e?ect decomposition bon, pumice, ?re brick, as well as synthetically prepared or naturally-occurring siliceous or alui 25 of the ‘deposited compound. Though variations‘ in the‘ method of preparing these “catalysts have been‘ disclosed, such methods have generally been ruinous materials such as, for example, clays, bentonite. bauxite, diatomaceous earth, silica ‘gel, handicapped by serious disadvantages. ' There Activated Alumina, active or activated blends or sulting catalysts are generally" lacking injg'u‘ni- ' compounds of silica and alumina, etc. “"These various types of carrier materials, though indi; 30 formity with respect to activity. Another disad vantage is the often total absence of a particular vidualiy applicable as supports for the catalyst as: characteristic such as, for example,‘ in the‘ case used in the execution of a number ofreactions, of catalysts comprising an element of group VIII are, however, not equivalent. It has been found and activated carbon, the ability to catalyze the that characteristics of the catalysts are‘often dependent upon the nature of the particular ‘1 ‘ conversion of ole?ns to a product predominating in the lower boiling of the linear polymers there upport material employed and that the catalytic eifect of the elements of group VIII may be modi ?ed or changed by judicious selection of a par of, ‘ ‘ ‘ The particular characteristic of the resultant catalyst, it has been found, is dependent not only ticular support material combined therewith. It has been found that catalysts comprising 4-0 upon the particular element of group VIII and the particular support material chosen but also upon the particular compound of the element of an element of group VIII in combination with activated carbon possess the ability of catalyz ing the conversion of ole?nic hydrocarbons to a group VIII used as a starting material. product which can be made to predominate in catalysts comprisingcobalt and/or nickel pre pared by combining an activated carbon with a one or several of the lower boiling‘ of the linear polymers thereof at temperatures below about 350° C. A particularly advantageous character istic of this catalyst combination is the ability to convert even the lower boiling of the ole?nic hydrocarbons, such as ethylene and propylene, to the lower boiling 'of‘=the linear polymers there of to a degree irlot‘prlo'ssessed by other types of available polymerizatibra catalysts. Their ability to promote the eoiiversion of ethylene and proa pylene to prodl?’ct'sfl predominating in- butylene l l . Thus, salt such as the acetate and chloride of these L". C. metals,v the subsequent reduction of these com-' pounds, produces a catalyst possessing little, if any, ability to promote the conversion of ethyl one to the lower boiling of the linear polymers thereof. On the other hand, when utilizing a salt‘ such as, for example, a salt obtained by the interaction of an element of group VIII with an‘ oxygen-containing mineral acid, for example, cobalt nitrate, nickel nitrate, etc., as starting, 2,407,814 - 3 4 materials, the resulting catalysts possess these use of others comprising stationary vessels is comprised within the scope of the invention. The rotating type of apparatus is preferred not ‘only because it enables the uniform distribution of the desirable characteristics to a surprising degree. However, the production of the catalyst from salts particularly prone to undergo spontaneous ignition during heating, such as 'the nitrates, especially when conducted on a large scale by methods utilized heretofore, often results in a spontaneous decomposition to varying degrees of the salt, therebynot only producing materials ineffective as catalysts but presenting serious 10 metallic element throughout the porous mass but because it enables the attainment of more effec tive mixing of the components Without attrition of the porous material to any substantial degree. It furthermore enables more uniform heating of the mixture thereby providing more effective con When the production of some mate trolof the rate of decomposition as well as more rial in the absence of marked spontaneous de efficient removal of decomposition‘ products and hazards. composition is attained by such methods, the resulting product nevertheless generally consists volatilized materials from the mass under treat . ment. In preparing the catalyst in accordance with of a substantial proportion which is lacking in 15 the invention a suitable inorganic porous mate the desired characteristic activity and a remain rial, for example, a porous granular carbon such ing portion which is devoid to a marked degree of uniformity with respect to composition and as activated vegetable or animal charcoals as pre catalytic activity. This, it is found, is due to at least a substantial degree to overheating of por 20 pared and activated by various commercial sup pliers, is introduced into a closed vessel prefer ably of the rotating type. Suction is thereupon applied to reduce the pressure within the vessel to subatmospheric, for example,~in the range of tions of the catalyst resulting from spontaneous ignition which, though present to a lesser'and localized degree is, nevertheless. often unavoid from about 1 to about 25 mm. of mercury. While ably encountered to an undesirable extent in methods of catalyst preparation resorted to here 25 maintaining the subatmospheric pressure a solu tion of the metal nitrate is introduced into the tofore. ' vessel. It is an object of the present invention to pro The salt is preferably introduced into the drum vide an improved method for the more e?icient preparation of catalytic materials comprising co dissolved in a suitable solvent of relatively low volatility. The particular solvent used may vary balt and/or nickel and activated carbon wherein and will depend upon the solubility of the par the above disadvantages are obviated to at least ticular salt therein. When utilizing cobalt ni a substantial degree. Another object of the in trate as a starting material water is found to vention is the provision of an improvedmethcd ‘for the ‘more 'e?icientmanufacture of catalysts be a suitable solvent. The amount of the salt comprising cobalt and/or nickel in combination 35 introduced into the vessel is dependent upon the nature of the particular catalyst to be prepared. with activated carbon having greater'uniformity with ‘respect to composition and catalytic activity In the preparation of catalysts, comprising co balt in combination with carbon, particularly ef fective for the conversion of ole?ns, it is preferred to add a suf?cient amount of the cobalt salt to the carbon to obtain a ?nished catalyst contain ing from about 3% to about 35% and preferably than those obtained by methods available here tofore. A still further object of ‘the invention is theprovision of an improved vmethod for the more efficient production, of catalysts comprising cobalt and/or nickel in combination with acti vated carbon. particularly effective in the con version of ole?nic hydrocarbons to the lower boils ing‘of the linear polymers/thereof. Other objects and advantagesof the‘ invention will become ap parent from. the following description thereof. 7 Inaccordance with ‘the present invention an from about 5% to 25% of cobalt. ' Catalytic materials comprising higher or lower concentra 45 tions of cobalt, depending upon the particular characteristics desired of the catalyst to be ob tained may, however, be prepared in accordance with the process of the invention. The concentration of the cobalt nitrate in the’ activated carbon is admixed in a suitable vessel with an aqueoussolution of a nitrate of cobalt 50 solution used as a starting material may vary and/or nickel. The-"resulting mixture is heated within the scope of the invention. In general, ' under conditionsassuring a slow and'gradual in it is preferred to employ a su?icient amount of crease in temperature of the‘ mixture to a maxi solvent for the cobalt nitrate to immerse the mum temperature not substantially in excess of greater. part of the mass of charcoal. , _ that enabling the maintenance of at least a part 55 The mixture is then agitated, for example, by of the solvent in the'vessel. Additional solvent rotation of the drum until intimate contact be is intermittently or continuously added to the» tween the solution and charcoal has been estab vessel during the heating operation until at least lished. The pressure in the drum is then in partial decomposition of the greater part of the nitrate has been effected. Thereafter the addi tion of solvent is stopped and the temperature slowly increased to a temperature not substan creased ‘to at least atmospheric pressure. By this’ procedure impregnation of the cobalt nitrate into the inorganic. porous material is obtained to the degree essential to the‘ attainment of a catalyst possessing sufficiently high activity as well as tially in excess of and preferably below the maxi mum temperature required to bring about the the characteristics essential for its use in such decomposition of the remaining portion of the 65 processes as the conversion of ole?nic hydrocar nitrate. When generation of decomposition bons to the lower boiling of the linear polymers products to any susbtantial degree has ceased, thereof. The invention is, however, not neces-~ the heating is discontinued. The catalyst is sarily limited to this particular method of im cooled and removed from the Vessel. pregnating the porous support materialand other In a preferred method of executing the inven 70 methods such as impregnation at atmospheric or tion the catalyst is prepared in a sealed rotating higher pressures before, proceeding with the drum provided ‘with means for heating and cool preparation in accordance with the invention ing its contents, removing volatilized material may be resorted to. ' therefrom and for varying the pressure therein. After impregnating the charcoal with the soluél Although this type of apparatus is preferred, the 75 tion'of cobalt nitrate heatis applied to the drum, 1 2,407,814 6 5 which is preferably rotated during the process, to attain a gradual increase in .the temperature of the contents therein without occasioning any sudden substantial increase in temperature. Dur ing the heating water vapor is continuously re moved from the drum, preferably by the apD1i~ cation of suction thereon. ‘The cobalt nitrate will undergo gradual decomposition even before the greater part of the water has been removed from the mixture in .t 1e drum. Resulting de composition products, comprising oxides of nitro gen, are removed from the drum together with the water vapor. The heating is continued for a period of time, and up to a. maximum tempera When at least the greater part of the salt charged to the drum has undergone substantial decomposition, which in the case of cobalt nitrate will be, for example, when at least 50% and pref~ erably about 70% or more of the combined nitro- ' gen has been removed from the mixture, the heating is continued at the maximum tempera ture prescribed for this phase of the process until substantially all of the water is removed 10 from the drum. The temperature of the con tents of the drum is then gradually increased, in the absence of any further addition of water, to a temperature not substantially in excess of about 400° C. and preferably not substantially in excess ture, not exceeding that assuring the presence of 15 of about 300° C. During this second heating period, decomposition products are removed from at least a part, for example about 20% of the the drum substantially as rapidly as formed. water in the drum. When utilizing cobalt nitrate The heating is continued, while maintaining the as the starting material a maximum temperature temperature of the contents in the drum within of, for example, about 110° C. and preferably of the prescribed temperature range, until no fur about 105° C. is not exceeded. When the greater ther generation of substantial amounts of decom part of the water has been removed from the mix position products is evidenced. The contents of ture, but prior to its complete removal, an addi the drum are then cooled and removed therefrom. tional amount of water is introduced into the Although the pressure Within the drum during drum and the heating operation is continued within the prescribed limited temperature range 25 the heating steps may be maintained at substan tially atmospheric, it is preferred to maintain the until the greater part of the water has‘ again been drum under partial vacuum to further the decom removed from the drum. The intermittent addi~ position of the cobalt nitrate and facilitate re tion of solvent is repeated until at least 50% and moval of vaporized solvent and decomposition preferably 70% or more of the combined nitro gen has been removed from the drum. 30 products therefrom. It has been found that par ticularly active catalysts are produced by em The amount of water added during the con ploying a subatmospheric pressure during that secutive additions may vary within the scope of phase of the heating process conducted after the invention. It has been found suitable to add removal of the solvent. Suitable reduced pres ‘an amount equal to about one half of the amount ?rst required to effect submersion of the catalyst. 35 sures comprise, for example, from about 25 mm. to about 250 mm. mercury pressure. The extent to Which it is removed prior to fur ther additions may also vary Within the scope of the invention. In general, it is preferred to add the additional amounts when about 89% of the water within the drum, comprising water of crystallization of the cobalt nitrate, has been removed therefrom. The amount of water re In a modification of the process of the inven tion the addition of the cobalt and/or nickel nitrate, for example cobalt nitrate, to the acti vated carbon is effected in successive steps. A part of the total amount of the cobalt nitrate to be added is initially introduced into the drum containing the carbon prior to beginning the moved prior to each successive addition may be heating. Successive‘ additions of cobalt nitrate progressively increased during the course of the operation, care being taken however, during this 43 are then made simultaneously with the subse quent additions of solvent during the heating phase of the process that all of the water be operation until the requisite amount of cobalt not removed. ’ nitrate has been added to produce the catalyst of The process may be modi?ed by effecting the the-desired composition. This, it has been found, addition of the solvent continuously instead of intermittently during this ?rst or decomposition L’ O often leads to more efficient catalyst production resulting in catalysts of unusually high activity. stage of the process. Under such conditions it is found advantageous, particularly when solvents Furthermore, it enables the production of active vent, optionally comprising the re?uxing of the avoided. catalysts containing higher proportions of the other than water are used, to provide condensing metallic element than methods wherein the ad~ means to which the eilluence from the drum may be passed and vaporized solvent condensed there 55 dition is effected in a single step. In preparing the catalyst in accordance ‘with in under conditions effecting the removal of de the invention, it has been found that sponta composition products therefrom in the gaseous neous ignition to any substantial degree of even state, and to return the condensed and cooled ich compounds as cobalt nitrate, so deleterious solvent to the drum. Under these conditions the temperature is, however, controlled in such man 60 to the activity of the ?nished catalyst, and which effect is inherent to a degree often preventing ner as not to exceed the maximum temperature economical production of such catalysts by of the permissible temperature range in the drum. methods available heretofore, is completely When utilizing the continuous addition of sol The resulting catalysts unlike those solvent, it is preferred to maintain a gradual in 65 produced by many other processes are not sub ject to wide variations in activity due to minor crease in the temperature gradient, up to the ?uctuations in the method of manufacture and maximum permissible temperature, during the are not only exceedingly uniform composition entire period of this phase of the process. but unusually stable upon contact with the atmos The solvent added subsequently to the primary impregnation need not necessarily be the same 70 phere and under storage conditions. The exact composition of the catalysts thus prepared com as that originally used .to introduced the salt into prising the cobalt and/or nickel in combination the drum. Under certain conditions it is found with carbon and which are particularly effective advantageous to utilize different solvents in the for the conversion or treatment of ole?nic hy impregnation step and in the subsequent solvent drocarbons is not readily determined. The co addition steps. 2,407,814 7 8 balt and/or nickel ‘may be present therein in the elementary form, in combination with oxygen, in 400 grams of water was added and the heating resumed for a period of 2 hours until the tem combination with carbon, or in a mixture or" perature again reached 105° C. Approximately these various forms. The carbon, in the partic 50% of the nitrogen had then been removed from the contents of the drum which still contained about 180 grams of Water. 400 grams of water was then again injected into the drum and heat ular catalysts comprising this material in com bination with cobalt and/or nickel prepared in accordance with the method of the invention, is not merely a diluent or support material but an active component of the catalyst in the absence ing continued for a period of 1/2 hour until the temperature of the contents was again gradu of which the catalytic e?ect upon such reactions 10 ally raised to 105° C. About 100 grams of Water as the conversion of normally gaseous ole?nic then remained in the mixture in the drum along hydrocarbons, particularly ethylene, to the lower boiling of the linear polymers thereof is only negligible if not completely absent. with about 30% of the combinednitrcgen. The heat was then adjusted to give a temperature rise of about 1° C. per minute until the temperature Materials capable of promoting or otherwise reached 300° C. After cooling, the catalyst, which modifying the activity of the ?nished. catalyst was almost identical in appearance with the orig inal charcoal, was removed from the drum and may be added thereto. Such materials compris ing, for example, elements other than cobalt charged to a reaction chamber. ‘ ‘ and/or ‘nickel, or compounds thereof, may be 140 cc. of catalyst prepared by the above pro added in relatively small amounts to the mate 20 cedure was charged to a stainless steel reaction rials in the catalyst drum during the course of tube. The catalyst was swept with Hz for 3 hours manufacture. The porous materials need not _ at 300° C. Ethylene was polymerized over the consist of a ‘material of but one type and may‘ catalyst at 100° C. under 800 pounds pressure. comprise a mixture of two or more inorganic The ethylene flow rate averaged 633 grams per materials of porous structure. Thus in the prep liter of catalyst per hour. In 70.9 hours the cat aration of catalysts comprising cobalt and/or alyst produced 18,600 grams of polymer per liter nickel in combination with carbon, inorganic of catalyst, 66% of which was butylene. The av-, material inert with respect to behavior of the erage conversion of ethylene to polymer was 42%. catalysts, such as, for example, pumice, crushed The catalyst was then regeneratedby sweep ing with Hz for 3 hours at 300° C. Polymeriza brick, bauxite, clays, etc., may be admixed with the charcoal prior to preparation of the catalyst or even during the course of its preparation. tion of ethylene was resumed under the above The additional incorporation of a porous mate» rial of more rugged structure enables the utiliza tion of carbon of smaller particle size and even in powdered form; the resultant catalyst then comprising an admixture of cobalt and/or nickel average flow rate of 794 grams of ethylene per liter of catalyst per hour. In 64.8 hours-21,200 and ?nely-divided carbon deposited upon a cen tral core of the added porous inert material. conditions of temperature and pressure and an grams of polymer were produced per liter of cat alyst, 59% of which was butylene. The average conversion of ethylene to polymer was 42%. I claim as my invention: a 1. In the preparation of catalysts comprising Catalysts prepared in accordance with the 40 cobalt and activated carbon particularly effective in the conversion of ole?nic hydrocarbons to the method of ‘the invention possess appreciable ac tivity and are ready to be utilized as such. It de--' lower boiling of the linear polymers thereof, the method of obtaining catalysts of substantially sired, however, the catalyst may be subjected to improved uniformity with respect to composition additional treatments culminating in still greater activity of the catalysts thus produced. Such and catalytic activity which comprises heating additional treatments may comprise subjecting ‘of the catalysts to higher temperatures in the order oi‘, for example, about 500° C., while sweep ing them with a gas consisting of or compris ing hydrogen, nitrogen, carbon dioxide, normally gaseous paraf?nic hydrocarbons such as methane, ethane, propane, or mixtures thereof. A method particularly, effective for further increasing the activity of catalysts of this type comprises their subjection to an elevated temperature up to, for example, about 500° C., while maintaining them at a subatmo'spheric pressure, preferably below about 10 mm. mercury. an admixture of an aqueous solution of cobalt ‘ nitrate and activated carbon in a closed vessel under conditions of progressively increasing “tem perature not substantially exceeding about 110° C., removing volatilized material and. gaseous de composition products from the vessel, introduc ing water in successively decreasing amounts into the vessel to assure the presence of water therein throughout said heating, continuing said heating in the presence of added water until at least‘a substantial part of the cobalt nitrate has under- . gone decomposition, and thereafter heating the’ contents of the vessel without further water ade ' dition at a higher temperature not substantially Example I 60 in excess of about 400° C. until evolution of sub stantial amounts of decomposition products has 1800 grams of 6-14 mesh granular cocoanut ceased. charcoal was introduced into arotating drum and the pressure therein reduced to 30 mm. of 2. In the preparation of catalysts comprising mercury. While rotating, a solution of 1800 cobalt and activated carbon particularly effective grams of cobalt nitrate hexahydrate in 800 65 in the conversion of ole?nic hydrocarbons to the grams of water was introduced into the drum. lower boiling of the linear polymers thereof, the Heat was applied to the rotating vessel while method of obtaining catalysts of substantially im maintaining the subatmospheric pressure. The proved uniformity with respect to composition heating was continued during a period of 3 and catalytic activity which comprises heating hours until a maximum temperature of 105° C. 70 an admixture of an aqueous solution of cobalt was attained. Approximately 80% of the Water ‘ nitrate and activated carbon in a closed vessel initially present (including water of crystalliza under conditions of‘ progressively increasing tem tion) was removed during this treatment along perature not substantially exceeding about 110°‘ with about 20% of the combined nitrogen, C., said cobalt nitrate solution containing insuf chiefly in the form of nitric oxide. At this point 75 ?cient cobalt nitrate to. provide the necessary 2,407,814 10 taining catalysts of improved uniformity with re spect to composition and catalytic activity which concentration of cobalt in the ?nished catalyst, removing volatilized material and gaseous decom position products from the vessel, introducing water in successively decreasing amounts into said comprises heating an admixture of activated car vessel to assure the presence of water ‘therein metal selected from the group consisting of co balt and'nickel in a closed vessel under condi throughout said heating, dissolving sui?cient co bon and an aqueous solution of a nitrate of a balt nitrate in at least a portion of the water so tions of progressively increasing temperature, re introduced during said heating to provide the moving volatilized material and gaseous decom position products from the vessel, introducing catalyst, continuing said heating in the presence 10 water into the vessel to assure the presence of water therein throughout said heating, continuing of added water until at least a substantial part said heating in the presence of added water until of‘ the cobalt nitrate has undergone decomposi at least a substantial part of the metal nitrate tion, and thereafter heating the contents of the has undergone decomposition, and thereafter vessel without further water addition at a higher temperature not substantially in excess of about 15 heating the contents of the vessel without further water addition at a higher temperature not sub 400° C. until evolution of substantial amounts stantially in excess of that required to effect de-' of decomposition products has ceased. composition of the remaining nitrate. 3. In the preparation of catalysts comprising 5. In the preparation of catalysts comprising cobalt and activated carbon particularly effective in the conversion of ole?nic hydrocarbons to the 20 activated carbon and a metal selected from the group consisting of cobalt and nickel, the method lower boiling of the linear polymers thereof, the ‘ of obtaining catalysts of improved uniformity method of obtaining catalysts of substantially necessary concentration of cobalt in the ?nished improved uniformity with respect to composition and catalytic activity which comprises heating with respect to composition and catalytic activity which comprises forming an admixture compris an admixture of an aqueous solution of cobalt 25 ing an activated carbon and a solution of a nitrate of a metal selected from the group‘c'onsisting of nitrate and activated carbon in a closed vessel cobalt and nickel in an aqueous solvent, heating said admixture in a closed vessel under conditions of progressively increasing temperature, remov troducing water into the vessel to assure the pres 30 ing volatilized material and gaseous decomposi tion products from the vessel, introducing Water ence of Water therein throughout said heating, into the vessel to assure the presence of water continuing said heating in the presence of added therein throughout said heating, continuing said water until at least a substantial part of the heating in the presence of added water until at cobalt nitrate has undergone decomposition, and thereafter heating the contents of the vessel with 35 least the larger part of the metal nitrate has undergone decomposition, and thereafter heating‘ out further water addition at a higher tempera the contents of the vessel without further addi ture not substantially in excess of about 400° C. tion of water to a higher temperature not sub until evolution of substantial amounts of decom stantially in excess of 400° C. until evolution ‘of position products has ceased. substantial amounts of decomposition products 4. In the preparation of catalysts comprising under conditions of progressively increasing tem perature, removing volatilized material and gas eous decomposition products from the vessel, in activated carbon and a metal of the group con sisting of cobalt and nickel, the method of ob has ceased. ' HARRY A. CHENEY.