Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Patent
1995-10-05
1997-02-25
Killos, Paul J.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
560254, 554187, C07C 6952
Patent
active
056061048
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/JP95/00061 filed Jan. 20, 1995 and published as WO95/21816 Aug. 17, 1995.
FIELD OF INDUSTRIAL APPLICATION
The present invention relates to a process for the preparation of an acyloxybenzenesulfonic acid or a salt thereof. In particular, the present invention relates to a process for preparing an acyloxybenzenesulfonic acid or salt thereof having an excellent hue by sulfonating an acyloxybenzene in the presence of a specific additive while suppressing side reactions.
PRIOR ART
An acyloxybenzenesulfonic acid salt can easily form an organic peroxy acid even at low temperature by the contact with a hydrogen peroxide generator represented by PC (sodium percarbonate) and PB (sodium perborate) or hydrogen peroxide in water to exhibit an efficacious bleaching power against dirts and stains on clothes and so on, thus being useful particularly as bleach activator (see EP-A 98021 corresponding to JP-A 59-22999).
A known process for the preparation of such an acyloxybenzenesulfonic acid salt comprises reacting a monosodium salt of phenolsulfonic acid with acetic anhydride to form sodium acetyloxybenzenesulfonate and adding a fatty acid having a desired alkyl chain to the product to conduct transesterification (see EP-A 105672 corresponding to JP-B4-1739). Although this process can give a high-purity product, the manufacturing cost is so high as to be unsuitable for commercial production, unless the acetic acid formed as a by-product has any use.
Meanwhile, there have also been disclosed various processes characterized by sulfonating an acyloxybenzene with a sulfonating agent such as SO.sub.3 as inexpensive techniques for preparing an acyloxybenzenesulfonic acid salt. However, the yields in these processes are very low, when the sulfonation is conducted by a mere reaction of an acyloxybenzene with a sulfonating agent. As the means for enhancing the yield, there have also been disclosed a process which comprises adding a small amount of a complexing agent for a sulfonating agent prior to the sulfonation (see EP-A 163225 corresponding to JP-A 60-258156) and a process in which the sulfonation is followed by continueing being heated (see EP-A 201222 corresponding to JP-A 62-30752). However, the yields in these processes are still as low as 90% or below, so that the occurrence of various side reactions is presumed. Under these circumstances, it has been expected eagerly to develop a process for preparing a desired acyloxybenzenesulfonic acid or a salt thereof at high selectivity in a high yield.
DISCLOSURE OF INVENTION
The present invention aims at providing an industrial process by which an acyloxybenzenesulfonic acid having an excellent hue can be prepared in an enhanced yield at enhanced selectivity and a lowered cost as compared with the processes of the prior art.
The present invention has been made to solve the above problem. The process of the present invention can suppress side reactions more effectively than those of the prior art, so that an acyloxybenzenesulfonic acid having an excellent hue can be prepared in a high yield at high selectivity and a low cost on an industrial scale. The present invention relates to a process for sulfonating an acyloxybenzene (1) to form a corresponding acyloxybenzenesulfonic acid (5) which is characterized by the addition of any additive selected from among carboxylic acids and esters thereof (2), alkyl phosphates (8), polyphosphoric acids (4), amide and like compounds (6). carbonic esters (7) and hydroxyl compounds. Further, it is preferable that the above sulfonation be conducted by the use of a thin-film reactor for sulfonation.
The present invention provides a process for the preparation of an acyloxybenzenesulfonic acid which comprises sulfonating an acyloxybenzene (1) represented by the general formula (1): ##STR1## (wherein R.sup.1 : a linear or branched alkyl or alkenyl group having 1 to 35 carbon atoms in total which may be substituted with a halogen atom or may have an ester group, an ether group, an amido group or a phenylene gro
REFERENCES:
The Journal of the American Oil Chemists' Society, vol. 32, pp. 170-172 1954.
Danjo Hiroshi
Hatayama Yoshio
Inoue Katsuhisa
Sotoya Kohshiro
Kao Corporation
Killos Paul J.
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