Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2002-08-12
2003-07-29
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C546S344000, C549S503000, C568S772000, C568S814000, C568S862000, C568S881000
Reexamination Certificate
active
06600078
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a heterogeneous process for the liquid phase hydrogenation of aldehydes to the corresponding alcohols using reduced form of CuO/ZnO catalyst in the presence of a metal from Group IIIA of the Periodic Table such as aluminium. More particularly, this invention relates to the hydrogenation of hydroxypivalaldehyde to neopentylglycol.
2. Description of the Prior Art
Aldehydes and corresponding primary alcohols are two general classes of organic compounds. There are several methods known in any textbook of organic chemistry and in patent literature for the conversion of aldehydes to the corresponding primary alcohols, such as chemical reduction methods using alkali or alkaline earth metal-derived borohydrides or aluminium hydrides and metal catalyzed-hydrogenation. Chemical reduction processes are seldom commercially viable. Usefulness of metal-catalytic processes is determined by conversion of aldehydes especially in presence of harmful impurities such as amines or other bases, selectivity of primary alcohol products, reaction conditions such as temperature and pressure, and even more importantly environmental issues caused by the metal catalysts.
Some of the conventionally used metal catalysts, although applied specifically for hydrogenation of hydroxypivaldehyde for making neopentyl glycol, may be equally effective to hydrogenate any aldehyde to the corresponding primary alcohol. This method is disclosed in Japanese Patent Publication Nos. 33169/1974,/ 17568/1678, U.S. Pat. Nos. 1,048,530, 1,219,162, 3,920,760, 4,021,496, West German Patent No. 1,014,089, and European Patent Nos. 44,421, 44,444. In these patents, Raney nickel, Ni—Cr, Cu—Zn, Cu—Al, Cu—Cr and Cr—Ba catalysts are disclosed as catalysts for use in such hydrogenation reaction.
These conventional catalysts suffer from problems in that the catalytic activity in insufficient and thus the reaction must be carried out under high pressure conditions and that catalytic activity can not be maintained at a high level for a long period of time since it is decreased under the influences of small amounts impurities contained in the starting materials, thee aldehydes. In the case of the Raney nickel catalyst, various problems arise; for example, preparation and handling of the catalyst are not easy, catalytic activity is insufficient and furthermore it can not be maintained for a long time, and since the catalyst is used in a slurry form, the process inevitably becomes complicated.
The followings are some of the prior arts related to our invention. For example, J. S. Salek et.al., in U.S. Pat. No. 5,146,012 (assigned to Aristech Chem) have disclosed the use of copper chromite for hydrogenation of hydroxypivalaldehyde to neopentylglycol. Chromium-based catalysts, in general, are now becoming environmentally unacceptable.
British Pat. Nos. 1,017,618 and 1,048,530, describe the hydrogenation of hydroxypivalaldehyde to neopentyl glycol in the presence of copper/chromium oxide catalyst. However, this catalyst system gave poor selectivity of neopentyl glycol due to formation of some by-products.
In other prior arts, such as in U.S. Pat. No. 4,250,337 (assigned to Chemische Werke Huls Aktiengesellschaft, Germany) and in U.S. Pat. No. 4,855,515 (assigned to Eastman Kodak, USA) barium and manganese-promoted copper chromite respectively have been disclosed as hydrogenation catalyst. The reactions were carried out at 500-1000 psig, and at a temperature of 170-220° C. It is now known that chromium-based catalyst pose health risks. Moreover, at high temperatures, this catalyst can decompose the starting material hydroxypivaldehyde adversely affecting the quality of final product and decreasing its yield.
German Published Application DAS No. 1,957,551 discloses the use of cobalt and nickel based catalysts in the hydrogenation of hydroxypivalaldehyde to neopentyl glycol, at high hydrogenation temperatures. Still another prior art WO 98/17614 (assigned to LG Chemicals, Korea) has described the use of Raney nickel in the hydrogenation of hydroxypivalaldehyde at low temperatures. But, these transition metal catalysts are deactivated by the presence of trace amounts of formaldehyde, or isobutyraldehyde, or trialkyl amine, which are present as impurities in the starting material hydroxypivalaldehyde. Besides, due to their pyrophoric nature these catalysts can not be easily prepared and handled as they have to be used in the slurry form.
T. Ninomiya et.al. have described in U.S. Pat. No. 4,933,473 (assigned to Mitsubishi Gas, Japan) the usage of a trimetallic (Pt/Ru/W) catalyst system for hydrogenation of hydroxypivalaldehyde. Although a 100% conversion of starting aldehyde and 100% selectivity of product are achieved at low reaction temperatures like 120° C., and at low pressure of 140-150 psig. a commercialization of this catalyst system is unlikely due to high cost of these metals.
In one of the closest prior art, EP 484800, the use of CuO/ZnO in presence of ZrO is disclosed for hydrogenation of hydroxypivaldeyhde wherein the use of 25% percent equivalent (by weight) of the catalyst makes the process commercially unattractive.
The closest prior art appears to be European Patent Application EP 008767 (assigned to Union Carbide) wherein CuO/ZnO catalyst system has been disclosed for reducing aldehydes to the corresponding primary alcohols. However, this process is severely limited only to a vapor-phase process, it did not become quite obvious to them if this catalyst system would have worked equally well in a liquid phase process, in general, with all other kinds of aldehydes such aromatic/or heterocyclic/or other branched aliphatic aldehydes.
Therefore, one of the objectives of the present invention is to overcome the difficulties and disadvantages encountered in the prior arts by providing a liquid-phase hydrogenation process utilizing a novel catalyst system comprising reduced form of CuO/ZnO in the presence of aluminium, a promoter for superior performance.
SUMMARY OF THE INVENTION
The present invention provides a liquid-phase general catalytic hydrogenation process for aldehydes to the corresponding primary alcohols. The catalyst system comprises of copper oxide and zinc oxide with aluminium as a promoter. The process of this invention, although general, is particularly useful for the hydrogenation of hydroxypivalaldehyde to neopentyl glycol. This process allows the hydrogenation to be carried out at moderate pressures such as 400-500 psig providing 100% conversion of aldehyde with 100% selectivity of the desired alcohol.
ADVANTAGEOUS EFFECT OF THE INVENTION
The efficiency of the catalyst is retained even in the presence of deleterious impurities like trialkyl amine and quaternary ammonium hydroxide that may have been carried over to certain crude aldehyde products during their synthesis.
This invention is particularly useful for making neopentyl glycol from hydroxypivaldehyde in 100% selectivity as this aldehyde does not decompose under hydrogenation conditions of this invention.
The particular product, namely 2,2-dimethyl-1,3-dihydroxypropane (neopentyl glycol) of the process of the present invention is a valuable starting material for the manufacture of lubricants, plastics, surface coatings and synthetic resins, for example corresponding polyesters.
The process of the invention may be a continuous process or a batch process.
DETAILED DESCRIPTION OF THE INVENTION
The following is the basic reaction of the present invention:
where, R
1
, R
2
, and R
3
individually could be straight chain or branched alkyl group containing 1-18 carbon atoms, or straight alkyl group containing 1-18 carbon atoms intervening with one or more hetero atoms such as oxygen, nitrogen, sulfur and phosphorus atoms, or alicyclic rings containing three or more carbon atoms when the ring(s) may or may not contain hetero atoms, or R
1
, R
2
, and R
3
together or alternately may form an alicyclic or aromatic rings, or any one or more of the R groups may contain one or more primary or
Al-Qahtani Abdullah
Anchoori Vidyasagar
Faizi Ahmad Kamal
Mahmud Meftahuddin
Levin Kramer
Naftalis & Frankel
Saudi Basic Industries Corporation
Shippen Michael L.
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