Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Metal – metal oxide or metal hydroxide
Patent
1995-06-06
1997-08-19
Caldarola, Glenn A.
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Metal, metal oxide or metal hydroxide
502344, 502 53, 502 56, 568864, 568885, B01J 2372, B01J 2370
Patent
active
056588437
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method for preparing a copper-containing hydrogenation reaction catalyst, and to a method for producing an alcohol. More specifically, it relates to a method for preparing a copper-containing hydrogenation reaction catalyst by a liquid phase reduction under specified temperature conditions, and to a method for producing an alcohol of high quality at a high productivity using the copper-containing hydrogenation reaction catalyst prepared by the above method, which has markedly improved catalytic activity and selectivity.
BACKGROUND ART
Since the 1930s a number of methods have been disclosed for producing aliphatic alcohols, alicyclic alcohols or aromatic alcohols by hydrogenating carboxylic acids or esters of carboxylic acids. In those methods, copper catalysts are mainly proposed for use in hydrogenation of esters of carboxylic acids, particularly fatty acid esters, and copper-chromium catalysts are commonly used for industrial purposes.
The conditions employed to activate these catalysts by reduction are determined depending on the form of catalysts and usage, reduction method and other factors. For example, when the fluidized bed reaction system is employed, a catalyst is used in a powder form. In Japanese Patent Laid-Open Nos. 1-305042, 5-177140 and 5-11718.5, it is stated that a catalyst may be activated by gas phase reduction or by liquid phase reduction in a solvent exemplified by hydrocarbons such as paraffin, ethers such as dioxane, alcohols and esters. Gas phase reduction, however, requires an additional apparatus other than the reactor for reductive activation of the powdery catalyst and further a surface stabilizing treatment for preventing the resulting copper from being oxidized by air. Because of these drawbacks of gas phase reduction, liquid phase reduction is generally employed in the fluidized bed reaction system. In this case, it is generally agreed that reduction is carried out preferably at a temperature of from 150.degree. to 350.degree. C. until hydrogen absorption has stopped. Since heat removal is easy in the case of powdery catalysts, local overheating can easily be prevented.
On the other hand, when a fixed bed reaction system is employed, gas phase reduction is exclusively used for the reductive activation of a formed catalyst, and for industrial purposes, it is common practice to carefully reduce a catalyst at a given temperature while supplying an inert gas containing several to several dozens percents of hydrogen, to prevent local overheating due to rapid reduction.
Reduction of copper oxide with hydrogen is generally known to generate a heat of reduction of 20 Kcal per mole of copper oxide and reduced copper thus obtained has a very low thermal stability. For this reason, it is important to gradually reduce the copper oxide while controlling heat generation to prevent the deterioration of its catalyst performance. When using a formed catalyst, in particular, this is critical because heat removal is difficult.
It is, therefore, very likely that when the catalyst is activated by gas phase reduction with a high concentration of hydrogen in a short time, a rapid heat generation considerably degrades catalyst performance, and that when a large amount of catalyst is activated by reduction in a short time on an industrial scale, a rapid rise in temperature causes a very dangerous situation. For this reason, it is common practice to use a low concentration of hydrogen over a long period of time for activation of catalysts containing copper oxide by gas phase reduction. For example, Japanese Patent Laid-Open No. 61-161146 states that it takes as long as 4 to 14 days for catalytic activation by such reduction, suggesting a disadvantage of gas phase reduction in view of alcohol productivity.
Also, DT 1768313 discloses a method for reductive activation of a copper-zinc oxide catalyst, in which the catalyst is gradually reduced at a temperature of between 120.degree. and 240.degree. C. in a hydrogen-containing nitrogen gas stream and
REFERENCES:
patent: 4537876 (1985-08-01), Blum et al.
patent: 4918248 (1990-04-01), Hattori et al.
patent: 5481048 (1996-01-01), Tsukada et al.
English Abstract of Japanese Document No. JP-A-5-177140 Jul. 1993.
English Abstract of Japanese Document No. JP-A-5-117185 May 1993.
English Abstract of Japanese Document No. JP-A-61-161146 Jul. 1986.
English Abstract of Japanese Document No. JP-A-62-298457 Dec. 1987.
English Abstract of Japanese Document No. JP-A-61-178037 Aug. 1986.
English Abstract of Japanese Document No. JP-A-1-127042 May 1989.
English Abstract of Japanese Document No. JP-A-2-26611 Jan. 1990.
English Abstract of Japanese Document No. JP-47-14113 no date.
English Abstract of German Document No. 3443277 Jun. 1985.
English Abstract of German Document No. 1768313 May 1977.
Hattori Yasuyuki
Mimura Taku
Nishigaki Futoshi
Tabata Osamu
Tsukada Kiyoshi
Caldarola Glenn A.
Kao Corporation
Preisch Nadine
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