Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2002-08-06
2003-09-09
Richter, Johann (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S861000
Reexamination Certificate
active
06617478
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates, in general, to a process for preparing a 1,3-alkandiol from a 3-hydroxyester. Specifically, the invention relates to a process for preparing a 1,3-alkandiol from a 3-hydroxyester in a liquid phase slurry manner with high yield and selectivity.
2. Description of the Related Art
1,3-alkandiols have been widely used as coating materials and intermediates for various organic syntheses, as well as for raw materials for the production of polyesters. At present, several process are known for preparing 1,3-alkandiols. For example, processes for preparing a 1,3-alkandiol by first hydroformylating an epoxide into a 3-hydroxyaldehyde derivative, and then hydrogenating the 3-hydroxyaldehyde derivative have been proposed (see: U.S. Pat. Nos. 5,770,776; 5,723,389; 5,731,478; and 5,777,182, the disclosures of which are incorporated by reference herein in their entirety). Alternatively, processes for preparing a 1,3-alkandiol by hydrating acrolein into 3-hydroxypropanal, followed by hydrogenation of the 3-hydroxypropanal, also have been proposed (see: U.S. Pat. Nos. 6,232,511 and 6,140,543, the disclosures of which are incorporated by reference herein in their entirety). Other methods have been disclosed that provide 1,3-alkandiols through a certain biological reaction, wherein glycerol is used as a starting material (see: U.S. Pat. Nos. 6,136,576; 6,013,494; and 5,821,092, the disclosures of which are incorporated by reference herein in their entirety).
Commercially, Shell Co. (Louisiana, U.S.A.) succeeded in producing 1,3-propandiol through hydrogenation of 3-hydroxypropanal resulting from the hydroformylation of ethylene oxide. However, the processes in which 3-hydroxyaldehyde or derivatives thereof, such as 3-hydroxypropanal, are generated as intermediates are disadvantageous in that these intermediates are so unstable that they likely will oligomerize themselves or be converted into other side products including acetals. Accordingly, hydrogenation thereof into corresponding 1,3-alkanediols often is not properly completed, and consequently, the quality of the final product is deteriorated.
Even though an alternative process was suggested, wherein a 1,3-alkandiol was prepared by carboesterifying an epoxide with carbon monoxide and an alcohol to produce a 3-hydroxyester, and then hydrogenating the ester group of the 3-hydroxyester, it has not been put to practical use in the industrial field. This is due to primarily to the fact that the reaction pathway is very unselective for 1,3-alkandiols when a conventional hydrogenation catalyst, such as copper-chromium oxide, copper-zinc oxide or Raney nickel, is used. Typically, hydrogenation of hydroxyester compounds having a hydroxyl group at a non-&bgr; position, which is involved in, for example, synthesis of 1,4-butanediol or ethyleneglycol, can readily be accomplished with high selectivity and yield because side products resulting from dehydration are produced in minor amounts. On the other hand, &bgr;-hydroxyester compounds including 3-hydroxyesters are likely to undergo dehydration reaction resulting in undesired side products.
While a number of Cu- or noble metal-containing catalysts have been studied and developed for use in preparing alcohols from their corresponding carbonyl group-containing compounds, particularly from esters, there have been reported few catalytic processes useful for preparing 1,3-alkandiols from 3-hydroxyesters having a hydroxyl group at the specific &bgr;-position. WO 00/18712 and U.S. Pat. No. 6,191,321, the disclosures of which are incorporated by reference herein in their entirety, disclose the use of a Cu/ZnO-based catalyst in preparation of 1,3-propandiol in the presence of an alcohol solvent such as methanol. While the alcohol solvent is helpful to suppress the self-lactonization and degradation of the reactant, 3-hydroxyesters, an alcohol with low boiling point is unfavorable because it cannot maintain high selectivity at a high conversion rate, and because it cannot maintain prolonged reaction stability of the catalyst under H
2
gas flow in a fixed-bed catalyst reactor. Moreover, the reactant, 3-hydroxyester, is not much different from the product, 1,3-alkandiol, in chemical properties and boiling point, which makes it difficult to isolate and purify the product from the reactant in the case of a low conversion rate.
Meanwhile, we proposed a process for preparing a 1,3-alkandiol from a 3-hydroxyester in a gas phase or liquid-gas phase manner, by the use of a CuO/SiO
2
-based catalyst that was shaped into nano-particles with a diameter of about 4 to about 10 nm (see: Korean Patent Application No. 2000-71643). According to the process, 1,3-alkandiols can be obtained with relatively high selectivity owing to high catalytic activity. However, it is difficult to increase the selectivity for 1,3-alkandiols to over 90% using this process, and generation of lactone and other side products with high boiling point likely occurs when the concentration of the reactant is high. Furthermore, the stability of the catalyst may be affected by possible degradation occurring in the course of reduction of the catalyst.
The description herein of certain disadvantages and inefficiencies of materials, processes and apparatus of the related art is in no way intended to limit the invention to embodiments that do not include these materials, processes and apparatus. Indeed, embodiments of the invention may incorporate the disclosed materials, processes and apparatus without suffering from the disclosed disadvantages and inefficiencies.
SUMMARY OF THE INVENTION
A feature of an embodiment of the present invention is to solve the above-mentioned problems of the related art, and to provide a novel process for preparing a 1,3-alkandiol from a 3-hydroxyester. It is a feature of the invention to increase the selectivity for 1,3-alkanediols to 90% or more, as well as to prolong the stability of the catalyst.
In accordance with these and other features of various embodiments of the invention, there is provided a process for preparing a 1,3-alkandiol from a 3-hydroxyester, comprising:
preparing a catalyst by adding an alkaline precipitator to an aqueous copper salt solution to form copper hydroxide particles, and ageing the particles following the addition of a colloidal silica thereto;
activating the catalyst through reduction with H
2
gas or H
2
-containing gas and applying a pressure of about 5 psig to about 2000 psig at a temperature of about 100° C. to about 250° C. in the presence of an activation solvent; and
hydrogenating a 3-hydroxyester in a liquid phase slurry with H
2
gas or H
2
-containing gas by applying a pressure of about 50 psig to about 3000 psig at a temperature of about 100° C. to about 250° C. in the presence of the activated catalyst and a reaction solvent to prepare a 1,3-alkandiol.
All of the above features and other features of the present invention may be successfully achieved and will be readily apparent to those skilled in the art from the detailed description that follows.
DETAILED DESCRIPTION OF THE INVENTION
Priority Korean Patent Application Nos. 2000-71643, filed on Nov. 29, 2000; 2001-33142, filed on Jun. 13, 2001; and 2001-67901, filed on Nov. 1, 2001, and parent U.S. patent application Ser. No. 09/995,798, filed Nov. 29, 2001, are incorporated herein in their entirety by reference.
In accordance with an embodiment of the present invention, Cu-containing catalysts stabilized with silica are applied to a hydrogenation process for preparing a 1,3-alkandiol from a 3-hydroxyester. The primary component of the catalysts is Cu in the form of an oxide, (e.g., CuO) and the weight ratio of the copper oxide (CuO) to silica (SiO
2
) in the catalyst is within the range of from about 95:5 to about 50:50. The silica-stabilized copper oxide catalysts can generally be represented by CuO—SiO
2
. However, the conventional CuO—SiO
2
catalysts prepared by impregnating a conventional silica carrier with copper oxide, for example, as describe
Han Yo Han
Jang Eun Joo
Jung In Sun
Kim Hyung Rok
Lee Byeong No
Lee & Sterba, P.C.
Pice Elvis O.
Richter Johann
Samsung Electronics Co,. Ltd.
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