Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1995-08-24
1997-03-04
Evans, Joseph E.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C07D30112, C07D30348
Patent
active
056080891
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a process for producing cis-epoxysuccinates. More specifically, the present invention relates to a process for producing highly pure cis-epoxysuccinates in a highly yield while suppressing the production of DL-tartrate produced as a by-product, by epoxidizing maleates with hydrogen peroxide in the presence of an epoxidation catalyst.
BACKGROUND OF THE INVENTION
In the past, there has been known a process for producing cis-epoxysuccinates, which comprises reacting maleates with hydrogen peroxide in an aqueous solution in the presence of an epoxidation catalyst such as tungstate or molybdate (G. B. Payne, J. Org. Chem. 24, 54, 1959). That process, however, when industrially applied, has suffered from the disadvantages of failing to avoid a large admixture of catalyst in the produced cis-epoxysuccinates, leading to not only the loss of the product quality but also the insufficiency of the recycling of an expensive catalyst, and as a result, it has seemed difficult of industrial practice also from the economical point of view.
There has also been proposed an improved process therefor, which is intended for producing an acid salts of cis-epoxysuccinic acid having a smaller water solubility than that of a normal salts of cis-epoxysuccinic acid, so that the catalyst may be more easily separated therefrom (Japanese Patent Publication (KOKOKU) No. 51-20490 and Japanese Patent Publication (KOKOKU) No. 54-29486). However, according to these prior processes, since pH of the reaction solution is in the acid range, the produced acid salts of cis-epoxysuccinic acid are further hydrolyzed to be converted to DL-tartrate. The production of DL-tartrate not only may bring about the loss of the product quality as well as that of the yield per unit weight of the starting maleate and hydrogen peroxide, but also the produced DL-tartrate may act as an epoxidation inhibitor. Consequently, it becomes necessary that such DL-tartrate is eliminated by any means, thereby disadvantageously complicating the catalyst recycling step. There can be considered an improved process therefor, wherein pH of the reaction solution is maintained in the neutral range. In such case, however, the yield of the acid salts of cis-epoxysuccinic acid may be remarkably decreased.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide an industrially advantageous production process of cis-epoxysuccinates, which improves the disadvantages of the previous processes for producing cis-epoxysuccinates.
Specifically, a process for producing a cis-epoxysuccinate comprising epoxidizing a maleate with hydrogen peroxide in the presence of an epoxidation catalyst, wherein the epoxidation is conducted in an aqueous solution containing 30 to 90% by volume of a water-soluble alcohol, whereby a highly pure cis-epoxysuccinic acid salt can be obtained in a high yield, while suppressing the production of DL-tartrate produced as a by-product. Further, it is possible to recycle a mother liquor freed of the produced cis-epoxysuccinate, by adding to a mother liquor a calcium compound and an alkali so that the tartrate produced as a by-product can precipitate in the form of calcium tartrate which is then separated and removed out of the system.
THE BEST MODE FOR ENFORCING THE INVENTION
The present invention will be described in more detail in the following.
According to the present invention, there can be produced acid salts of cis-epoxysuccinic acid which may easily be converted to cis-epoxysuccinic acid and normal salts of cis-epoxysuccinic acid. One of the conditions to be specified for producing acid salts of cis-epoxysuccinic acid is that maleates are acid salts of maleic acid. For instance, when acid salts of maleic acid produced by reacting maleic anhydride or maleic acid with equimolar amount of a base thereto is present in a reaction system, thus produced acid salts of maleic acid can easily be epoxidized with hydrogen peroxide in the presence of an epoxidation catalyst to obtain acid salts of
REFERENCES:
patent: 3156709 (1964-11-01), Allan
patent: 3769339 (1973-10-01), Wagner et al.
patent: 4026908 (1977-05-01), Pralus et al.
patent: 4065475 (1977-12-01), Hosoi et al.
Ida Kazutaka
Murayama Kenji
Sato Keiichi
Evans Joseph E.
Mitsubishi Chemical Corporation
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