Preparation of acyloxybenzenesulfonic acids and their alkali metal and alkaline earth metal salts

Acyloxybenzenesulfonic acids and their alkali metal and alkaline earth metal salts are prepared by a process comprising sulfonation of a phenyl ester in the presence or absence of a small amount of a complexing agent for the sulfonating agent SO.sub.3 or chlorosulfonic acid, subsequent acylation and, if desired, neutralization to give the alkali metal or alkaline earth metal salt, and, if required, subjecting the latter to oxidative bleaching before drying.

EXAMPLES 
The Examples below were carried out using compounds in which R was 
3,5,5-trimethylpentyl, unless stated otherwise. Other acyl radicals 
exhibit entirely similar behavior. The content of acyloxybenzenesulfonic 
acid in the reaction mixture is advantageously determined after 
neutralization with aqueous sodium hydroxide solution and spray-drying, on 
the isolated sodium salts, by means of two-phase titration according to 
DIN/ISO 2271. Parts are by weight. 
General Methods 
A. Preparation of the Phenyl Esters as Starting Compounds of the Formula II 
1. 94 parts of phenol were melted, and 176 parts of 3,5,5-trimethylhexanoyl 
chloride (isononanoyl chloride) were added at 45.degree. C. in the course 
of from 1 to 2 hours, while stirring. Stirring was continued for 1 hour at 
50.degree. C. 
2. 158 parts of isononanoic acid, 103 parts of phenol and 60 parts of 
toluene were heated at the boil with 1 part of p-toluenesulfonic acid and 
0.3 part of hypophosphorous acid. 15 parts of water were separated off by 
azeotropic distillation at from 140.degree. to 160.degree. C., after which 
the toluene and the excess phenol were distilled off under 20 mbar at up 
to 140.degree. C. The crude phenyl ester obtained was purified by 
distillation at from 140.degree. to 160.degree. C. and under reduced 
pressure of about 20 mbar. The yield was 187 parts (80%). 
B. Sulfonation of the Phenyl Esters without Complexing Agents 
Either 122 parts of chlorosulfonic acid or 84 parts of sulfur trioxide, 
according to the Table, were added to 234 parts of phenyl isononanoate at 
from 25.degree. to 55.degree. C. in the course of from 1 to 2 hours, 
stirring was continued for 1 hour at 50.degree. C., and the hydrogen 
chloride was then removed under reduced pressure of from 10 to 20 mbar. 
C. Sulfonation of the Phenyl Esters with Complexing Agents 
The complexing agents shown in the Table were added to 234 parts of phenyl 
isononanoate. 122 parts of chlorosulfonic acid or 84 parts of sulfur 
trioxide were run into the cooled mixture in the course of from 1 to 2 
hours at a rate such that the temperature did not exceed 55.degree. C. 
Stirring was continued for 1 hour at 50.degree. C., after which the 
hydrogen chloride was removed under reduced pressure of from 10 to 20 
mbar. 
D. Subsequent Acylation 
The amount of phenolic OH groups present in the crude 
acyloxybenzenesulfonic acid was determined by titration with 1N aqueous 
sodium hydroxide solution using a Metrohm Titroprocessor (manufactured by 
Metrohm), and the said OH groups were then esterified with an equimolar 
amount of isononanoyl chloride in the course of 2 hours at 50.degree. C. 
In the case of procedure B or C, from 4 to 20 parts of isononanoyl 
chloride were required for this purpose. 
E. Neutralization and Oxidative Bleaching 
100 parts of the crude acyloxybenzenesulfonic acid obtained were run into 
100 parts of water, while stirring thoroughly. At the same time, 50% 
strength by weight aqueous sodium hydroxide solution was added dropwise so 
that the aqueous solution was brought to a pH of from 3.0 to 5.5 
(monitored by means of a glass electrode). The temperature of the reaction 
mixture was kept below 50.degree. C. by cooling. When the addition of the 
acyloxybenzenesulfonic acid was complete, the solution was brought to pH 
5.5. For oxidative bleaching, 0.1 part of sodium perborate was added and 
the solution was then heated at 50.degree. C. for 6 hours. The sodium salt 
was isolated from the aqueous solution by spray-drying. 
F. Preparation of Sodium n-pentanoyl- and Undecanoyloxybenzenesulfonate 
1. 188 parts of phenol were melted, and 269 parts of caproyl chloride 
(n-pentanecarbonyl chloride) were added at 45.degree. C. in the course of 
from 1 to 2 hours. Stirring was continued for 1 hour at 50.degree. C., 
after which 8 parts of dimethylformamide were added. 
244 parts of chlorosulfonic acid were run in over 1-2 hours at a rate such 
that the temperature did not exceed 55.degree. C. 
Stirring was continued for 1 hour at 50.degree. C., after which the 
remaining hydrogen chloride was removed under reduced pressure of from 10 
to 20 mbar. 
The crude sulfonic acid obtained was worked up as described in Examples D 
and E. Content: 81.1% of Na salt. 
2. 141 parts of phenol, 328 parts of lauroyl chloride (undecanecarbonyl 
chloride), 8 parts of dimethylformamide and 183 parts of chlorosulfonic 
acid were reacted with one another, and the reaction mixture was worked 
up, these steps being carried out as described in Example F1. Content: 
85.3% of active substance (Na salt). 
TABLE 
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Examples according to process steps B to E 
Content of Na salt.sup.2 
of the acyloxybenzene- 
Example 
ClSO.sub.3 H 
SO.sub.3 
Complexing agent 
Parts 
Mole %.sup.1 
sulfonic acid 
__________________________________________________________________________ 
1 x -- -- -- -- 75.7% 
2 -- x -- -- -- 74.3% 
3 x -- dimethylformamide 
2.34 
3.0 85.0% 
4 x -- dimethylformamide 
4.68 
6.1 84.1% 
5 x -- dimethylformamide 
9.36 
12.3 87.6% 
6 x -- dimethylformamide 
14.04 
18.3 86.4% 
7 x -- dioxane 4.68 
5.0 86.7% 
8 x -- dioxane 14.04 
15.2 86.5% 
9 x -- dioxane 23.4 
25.3 84.5% 
10 x -- urea 4.68 
7.4 84.3% 
11 x -- tetramethylurea 
4.68 
3.8 86.6% 
12 x -- tetramethylurea 
9.36 
7.6 83.8% 
13 x -- imidazole 4.68 
6.6 83.1% 
14 x -- diisobutylformamide 
4.68 
4.5 82.6% 
15 x -- melamine 2.34 
1.8 81.8% 
16 x -- benzoguanamine 
4.68 
2.4 81.2% 
17 x -- N--methylpyrrolidone 
4.68 
4.0 82.4% 
18 x -- N--methylpyrrolidone 
9.36 
7.9 84.7% 
19 x -- dimethylcyclohexylamine 
9.36 
7.0 83.0% 
20 x -- succinimide 9.36 
9.0 85.9% 
21 x -- phthalimide 9.36 
6.0 82.7% 
22 x -- triphenylphosphine 
9.36 
3.4 84.5% 
23 x -- ethylene glycol dimethyl 
4.68 
5.0 
ether 
24 -- x dimethylformamide 
11.17 
14.6 80.9% 
25 -- x triethylamine 
9.36 
8.8 80.7% 
26 -- x phthalimide 9.36 
6.0 78.7% 
27 -- x tetramethylurea 
9.36 
7.6 79.5% 
28 -- x dimethylcyclohexylamine 
9.36 
7.0 77.3% 
29 -- x N--methylpyrrolidone 
9.36 
7.9 82.0% 
30 x -- dimethylformamide 
44 57 71.8% 
31 x -- dimethylformamide 
73 100 79.2% 
32 -- x dimethylformamide 
73 100 -- 
33 x -- urea 60 100 -- 
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.sup.1 based on sulfonating agent 
.sup.2 twophase titration according to DIN/ISO 2271 
The values in the Table show that the addition of complexing agents, 
particularly where chlorosulfonic acid is used, results in a yield about 
11% higher than that obtained without the addition of these complexing 
agents. 
Examples 30 to 33 are comparative examples, about which the following may 
be stated: the use of dimethylformamide in an amount of 57 mole % leads to 
a substantially lower content of active substance (Example 30). 
Regarding Example 31, reaction with an equimolar amount of 
dimethylformamide gave a content of active substance of 79.2%, the 
temperature having to be increased to 90.degree. C. since no reaction took 
place at 55.degree. C. The higher temperatures had the effect of imparting 
a pronounced dark coloration to the product, in spite of bleaching and 
additives. 
Examples 32 and 33 gave inhomogeneous mixtures which did not react in the 
temperature range according to the invention, up to 80.degree. C.