DE1089168B - Process for the production of anti-aging agents - Google Patents

Description

It is known that anti-aging agents are obtained when o-, p-dialkylated phenols are mixed with formaldehyde implemented (see US Pat. No. 2,538,355). The production of these compounds on an industrial scale creates difficulties, however, since only then sufficient yields of the crystalline compounds are obtained obtained when using o-, p-dialkylphenols, the are not contaminated by by-products, since monoalkylphenols have a resinifying effect during the reaction and very greatly reduce the yield of crystallized compounds. It is also necessary that you have the Condensation of the dialkylated phenols with the formaldehyde is carried out under such conditions that none Dealkylation to monoalkylphenols occurs. Under these conditions, the condensation with the formaldehyde takes place but not quantitatively, and the mother liquor has to be used again to improve the yield.

It has now been found that anti-aging agents are obtained in a simple manner if p-alkylphenols are used first alkylated with an olefin or a secondary or tertiary alcohol in a known manner and that reaction mixture obtained then condensed directly with formaldehyde.

Suitable p-alkylated phenols are, for. B. p-methylphenol, p-ethylphenol or p-propylphenol. The alkylation these phenols can be made in a conventional manner, e.g. B. with ethylene, propylene or isobutylene or with appropriate alcohols, such as. B. tert-butanol, cyclohexanol and isopentanol. The alkylation is preferably carried out in a molar ratio of 1: 1, but it is also possible to use less than 1 mol, e.g. B. 0.5, or more than 1 mole, e.g. B. 1.5 moles, use of the olefin. The alkylation is expediently carried out at an elevated temperature, as usual in the presence of a catalyst, made such. B. in the presence of activated Fuller's earth.

The reaction mixture obtained in the alkylation is then used directly in a manner known per se Formaldehyde condenses. Here too, the condensation is expediently carried out in the presence of known catalysts, such as. B. activated fuller's earth, sulfuric acid or hydrochloric acid. In many cases it can both the alkylation and the condensation can be carried out with the same catalyst. In some Cases, however, it can be useful to use different catalysts, each of which give the best results.

The reaction products obtained in the process according to the invention surprisingly have a very good effect as an anti-aging agent that hardly differs from that of the crystallized compounds. It is particularly advantageous that the compounds obtained according to the invention are also very good Have lightfastness.

Method of manufacture
of anti-aging agents

Applicant:

Paint factories Bayer Aktiengesellschaft, Leverkusen-Bayerwerk

Dr. Josef Haveln and Dr. Hermann Holzrichter,

Leverkusen-Bayerwerk,
have been named as inventors

The compounds obtained are yellowish or brownish clear resins.

example 1

In 108 parts (1 mole) of p-cresol was added in the presence of 7 g of activated bleaching earth as catalyst at 14O ⁰ C under stirring, 100 g (1 mol) of cyclohexanol, so that the cyclohexene produced by dehydration is continuously consumed. The water is removed by azeotropic distillation. After the entry has ended, the temperature is kept at 140 to 150 ^° C. for a further 3 hours and then cooled. With the addition of a further 7 g of the same contact the reaction mixture with gasoline diluted 1: 1, added over 3 to 4 hours at 70 to 8O ⁰ C portionwise with 17 g (0.57 mol) of paraformaldehyde and further

Heated to 90 ^° C. for 6 hours. The contact is removed by filtration and, after the solvent has been distilled off, the residue obtained is an anti-aging agent whose properties in terms of anti-aging and lightfastness correspond to 2,2'-dioxy-3,3'-dicyclohexyl-5,5'-dimethyl-diphenylmethane .

Example 2

In 108 parts (1 mol) of p-cresol are in the presence of

7 g of activated clay introduced so as catalyst at 60 to 9O ⁰ C with stirring, 56 g (1 mole) of isobutylene, that the temperature remains below 90 ^0C. After the reaction has ended, the reaction mixture is freed from the catalyst by filtration and diluted with the same amount of gasoline. Then with the addition of 15 g of concentrated hydrochloric acid as a catalyst with stirring at 40 to 6O ⁰ C 46 g of a 36 ° / "aqueous formaldehyde solution (= 16.5 g of formaldehyde, 100 ° / ₀ ig = 0.55 mole) was added and it is heated to 6O ⁰ C. for 6 hours. The solution is washed several times with

009 607/442

1

Water freed from the acidic catalyst at 60 ° C: and the solvent is then distilled off. The residue corresponds in its properties as an anti-aging agent 2,2'-dioxy-3,3'-di-tert-butyl-S, 5'-dimethyl-diphenylmethane.

Claims (1)

Claim: Process for the preparation of anti-aging agents, characterized in that p-alkylphenols are first alkylated in a known manner with olefins or secondary or tertiary alcohols and the resulting reaction mixture is then condensed directly with formaldehyde in a manner known per se. Considered publications:
German Auslegeschrift I 6702 IVb / 12o (published on 27.09956).