Patented Sept. 24, 1946 I I I _ ‘ 2,408,131 omcE PATEiN'lT 1 Alexis Ycerhies, in, Baton Badge, La; assigleatie "Standard‘Oil‘Dey lopment C ration. ethdeware any, a Y" ‘ - " No Drawing. Application October 2_'1_, 1951, ~ "Serial. No- 415,903“ Q 1 . (Cl. 260-6833) ._,... ..,i I . ' It, 2 I I I have now vfound that a catalyst comprising a major proportion of_ aluminum oxide and a minorproportion of chromium oxide can bemade __ I, I I _ _ I I substantially" more heat'ijes'istant‘and fébyI . ,I .. I.. 'YJt'oi a sl'ubstant'ialfeI entj'wlien heated 5I retaIiIiji _its"ac_tivity 'atus'ubusta tially higher'teini to‘témperatures“ at" which 'the' knowntypeswo'f ‘" peratures if approximately on I) catalysts firearm-these' " 1051,: their activity; e an‘dwjith'the ~' " ~ ‘ method > c i I I V mium. re arising.(aide ahaiit.iterated i 96%. altimeter; tailed. ttat'arezeaiia niqkel'bxidei .QX 2% "9 bi miuraexide and 2% air Pit-ht. . ' tateniperataifesbetweee 'liitqaed l 00° F‘ with: out. loses its aqtivitv to. art appreciable exitent Wh¢17§ét§ a; ‘catalyst, camel: ?ne ‘2% eliminate oiéide and 61% geranium 9X 6 loses. a tutti?? tial amount of itsaetiu. r " 1600“ F. .sieeheetss'l at}??? ' » a » - inven vert the nitrate to the oxide. In order to increase the mechanical Str'eng'thand durability of the catalyst it may be heated to a high temperature, equal amounts. say above 1000° F., at which temperature a sub- . These catalysts may be prepared by impreg stantial amount of volatile matter and moisture hating Activated Alumina, alumina gels, peptized is driven off. In general it‘ may be said that the 25 alumina gels, bauxite, alumina lrlydraiiesv and higher the temperature to which this type of other forms of aluminum oxide with a mixture ‘ . Catalyst is heated, themore rugged it will become, However, it is noted that as the temperature of heating is increased, the catalyst tends to become “ less active. 30 The ability of a catalyst to retain its activity when heated to high temperatures is important not only in the preliminary heat treatment to increase mechanical strength but also in the catalytic dehydrogenation reaction itself and in the 35 regeneration of the catalyst when its activity has been reduced by the deposition of carbonaceous contaminants thereupon. Thus it frequently happens during the dehydrogenation reaction, of solutions of chromium and nickel nitrates and then heating the resulting mass to temperatures between 600, and 800° F. The concentration of chromium and nickel nitrates in the solution are adjusted so that the ?nal heated mass will con tain the desired quantities of Chromium and nickel oxides. It Will be understood that soluble salts 01" Chromium and nickel other than the nitrates may be used for impregnating the alu mimlm 0Xide~ The following experimental data indicate the heat resistant pr?perties 0f the improved Cat all/‘St in Comparison With those of the knOWn and particularly during the regeneration, that 40 Catalyst! ' ' excessively high temperatures may be developed T‘WO Catalysts are prepared, One Consisting of in local spots in the catalyst mass and if these 96% Activated Alumina and 4% Chromium Oxide temperatures are high enough to cause loss of activity it can be seen that care must be taken and the other consisting of ' 96% Activated Alumina, 2% chromium oxide and 2% nickel to prevent such local overheating. In regen- 45 oxide. Isobutane is passed over each catalyst at crating the catalyst it is of great advantage to a rate of 175 volumes of isobutane per volume of be able to conduct the regeneration at as high Catalyst liar hour at a temperature of 1075° F a temperature as possible because this means In the first experiment the Catalysts are not Dre that the necessity for constant cooling. of~the ' heated to a high temperature- In the Second, catalyst mass is greatly reduced, It can be Seen 50 third and fourth experiments the catalysts are therefore that if the catalyst is one ‘which loses heated to temperatures of 1600° F., 1800° F. and its activity when heated to certain temperatures’, care must be taken to prevent these temperatures from being reached either during thereaction period or during the regeneration period. _ , 2000“ F. respectively. The following tables show the results obtained. In the table the catalyst containing 4% chromium oxide and no nickel 55 Oxide will be designated as Catalyst A, and the 2,408,131 ' l 4 3 alyst which consists of about 96% by weight of aluminum oxide, 2% by Weight of chromium oxide and 2% by weight of nickel oxide, and catalyst containing 2% chromium oxide and 2% nickel oxide will be designated as catalyst B: - Experiment- #1 no preheating A B Experiment #2 . preheating to 16000 F_ A which has been heated to a temperature between 5 1800° and 2000° F. 2. The process of dehydrogenatinghydrocar bons having from 2 to 5 carbon atoms which com B prises passing the hydrocarbons at dehydrogen ating temperatures and pressures over a catalyst Per cent unsaturates in exit gas-_ Per cent isobutylene in unsatur 29 26 26 26 ates __________________________ _ _ 89 89 94 9Q which contains about 96% by Weight of alumi num oxide, 2% by weight of chromium oxide and 2% by weight of nickel oxide, and which has been heated to a temperature between 1800° Experiment #3 Experiment #4 preheating to preheating to 1800° F. 2000° F. A B A and 2000° F., and regenerating the catalyst by 15 removing coke deposits at intervals substantially at temperatures of the regeneration reaction without constant cooling. 3. The process of dehydrogenating hydrocar bons having from 2 to 5 carbon atoms which B Per cent unsaturates in exit gas._ Per. cent lsobutylene in unsatur 14 ‘20 8 12 ates __________________________ _ _ 64 88 65 82 genating temperatures and pressures over a It will be noted that when the two catalysts are heated to temperatures of 1600° F., they are catalyst which consists of a major proportion of aluminum oxide and minor substantially equal proportions of chromium oxide and nickel oxide substantially equivalent in activity as represented by the fact that about the same amount of un saturates are produced and about the same per centage of the unsaturates consists of isobutylene. However, when the catalysts are heated to 1800° F., it will be noted that there is a marked de crease in the percent of unsaturates and percent comprises passing the hydrocarbons at dehydro 20 2% 4. The process of dehydrogenating hydrocar bons having from 2 to 5 carbon atoms which comprises passing the hydrocarbons at dehydro genating temperatures and pressures over a cat alyst which contains a major proportion of aluminum oxide and minor substantially equal proportions of chromium oxide and nickel oxide of isobutylene produced with catalyst A, where as the decrease with catalyst 13 is not nearly so great. This tendency is even more marked when both catalysts are heated to 2000° F. _ and which has been heated to a temperature 35 I'claim: l _1. The process of dehydrogenating hydro carbons having from 2 to 5 carbon atoms which comprises passing the hydrocarbons at dehydro- ‘ genating temperatures and pressures over a cat and which has been heated to a temperature between 1800° and 2000° F. 46 between 1800° and 2000° F., and regenerating the catalyst by removing coke deposits at inter vals substantially at temperatures of the regen eration reaction without constant cooling. ALEXIS VOORHIES, JR.