US2502348A - Catalysts - Google Patents

Description

Patented Mar. 28, 1950 CATALYSTS.

Igor Scriabine, Jean Franc'isque Billan, Alfred Felix Sebastien Bellone, and Maurice Gaillard, Lyon, France, assignors to Societe des Usines Chimiques Rhone-Poulenc', Paris; France, a

company of France:

No Drawing. Application February 27', 1946, Serial N 0. 650,758. In France November 20, 1944 Section 1. Public Law 690, August; s, 1946 Patent. expires November 20, 19614- 1 Claim.. (01. 252-470)v 1 The present invention relatesto new nickel catalysts characterised by containing chromium in the proportion of (7.5 to 3.5% of the nickel. It also concerns the application of these new catalysts to the hydrogenation of organic substances.

The process for the preparation of nickel catalysts from an alloy of nickel with a metal such as aluminum which can be. then eliminated by an alkaline treatment is known. There is thus Obe" tained. a nickel endowed with very greatcatalytic activity.

According to the present invent on it has been found that in the method of working previously described if one causes chromium to be introduced as a third constituent of the alloy in the propor tion of 0.5 to 3.5% of the nickel there is obtained after elimination of the aluminum, a catalyst which is notably superior to those not containing the chromium.

The chromium can be introduced into the alloy in any convenient fashion. One can for example make use of an aluminum-chromium alloy obtained by the aluminum thermite process starting from aluminum and chromium oxide; more simply the chromium can be introduced in the form of commercial ferro-chrome, as it has been found in practice that the presence of iron in the catalyst finally obtained does not affect the activity of the latter.

The alloy containing the aluminum, the nickel and the chromium is treated according to the same processes as those usually used in the case of binary alloys, that is to say, pulverised and attacked by an alkaline solution (for example caustic soda or potash). In this manner as is known it is possible to effect only a superficial attack of the crushed alloy, so that in elTect one obtains a catalyst on a support which can be used for example in the known manner in hydrogenation apparatuses of the type in which the catalyst is fixed and the liquid circulates.

. The catalysts accordin to the invention show the following advantages over catalysts not containing chromium:

1. Using the same quantity of catalyst, they give at least equal yields and in a much shorter time;

2. In a series of hydrogenations made without bringing fresh catalyst into use, the yield and the speed of the hydogenation decreases much more slowly;

3. In a series of hydrogenations in which a certain quantity of catalyst is removed after each operation and replaced by an equivalent quantity of fresh catalyst, the quantity of catalyst required for replacementineachoperation. inorder to. maintain the yieldand. the speed of absorp ltionof the hydrogenation constant is very much ess.

The following example, without in any way limiting the. invention, describes a, method for the preparation and use of thecatalyst, atv thev same time showing, by comparison the surprisin ac.- tivity of the catalysts. The parts referred to are parts by EXAMPLE (A) Preparation of the alloy Per cent Al 61.1 Ni 35.4 Cr 0.43 Proportion of Cr to Ni 1.2

(B) Preparation of the catalyst The alloy is crushed, then powdered and then treated with caustic soda according to the known processes used for attacking nickel-aluminum alloys.

(0) Application to the hydrogenation of adiponitrile In an autoclave fitted with stirring gear there are placed Parts Adiponitrile 600 Methanol 475 Caustic potash (solution of 48 B.) 15 Catalyst 48 The hydrogenation is effected under a pressure of 15-20 kg./cm. and at a temperature of -67 C. At the end of an hour, the absorption of hydrogen ceases: the yield o fhexamethylenediamine is 92 of the theory. If a series of hydrogenations is effected by decanting the liquid and allowing the catalyst to remain in the autoclave and then recharging the autoclave in the same fashion but without adding fresh catalyst, the yield falls from 92 to 86% for the fourth operation, the duration of the hydrogenation increasing in parallel from one hour to 2 hours. In the case of a nickel catalyst prepared in the identical fashion but without the addition of the ferro-chrome, all the other conditions remaining the same, the yield which is only 90% for the first operation, falls to 57% for the fourth, While the duration of the hydrogenation increases from 2 hours to 10 hours. In another series of operations made in a medium of ethanol it was possible to maintain the yield at 90-91% and the duration of hydrogenation at 1 hour to 1 hour 15 minutes for ten operations by charging in the first operation a quantity of catalyst equal to 8% by weight of the nitrile and replacing after each operation -6% of the catalyst used by an equal quantity of fresh catalyst, the conditions of temperature and pressure being the same as in the series previously mentioned. With the catalyst not containing chromium under the same conditions of temperature and pressure it was necessary in order to ensure the constancy of the yield of hexamethylenediamine (90-91%) and the duration of the hydrogenation (about 2 hours) to utilise at the beginning 10% of the catalyst (calculated on the nitrile) and to replace about 20% of it at each operation.

What we claim and desire to secure by Letters Patent is:

Finely divided porous nickel hydrogenation catalysts consisting essentially of a nickel-chromium alloy in porous, activated form, said chromium being present in a proportion of from 0.5 to 3.5% of the nickel content, and the remainder being substantially nickel.

IGOR SCRIABINE.

JEAN FRANCISQUE BILLAN.

ALFRED FELIX SEBASTIEN BELLONE. MAURICE GAILLARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Ser. No. 357,989, Brendlein (A. P. C.) published May 25, 1943.

Aufbau der Zweistofilegierungen, by Hansen, Berlin, 1936, Edwards Bros. Inc., 1943, pp. 541 and 543.