DE1051864B - Process for the preparation of optionally substituted dioxy-diphenylmethanes - Google Patents

Description

Process for the preparation of optionally substituted dioxydiphenylmethanes It is known to acidic formaldehyde with phenols and phenol homologues in the presence Condensing agents, such as. B. hydrochloric acid, sulfuric acid and other mineral acids, to implement. Furthermore, it has already been suggested that the acids on carrier materials, such as Porous clay, the acid content being e.g. B. 33 percent by weight can be (see US Pat. No. 2572141). Also sulfonic acids and acid-splitting ones Agents such as phosgene, thionyl chloride, aluminum chloride etc. are already used for the condensation reactions has been described. One characteristic common to all of these means is more or less acidic character. The consequence of these properties is that, in particular if higher temperatures are required, the implementation Such processes on an industrial scale lead to considerable difficulties in terms of corrosion engineering Respect leads. In some cases these are due to the use of acidic condensing agents caused corrosion to such an extent that it is a laboratory scale Reaction proved to be useful cannot be transferred to an industrial scale can. Aside from such corrosion problems, there are various reasons too strong action of acidic catalysts of detrimental influence on the further Course of the process with regard to a complication of the work-up and the achievable yields.

It has now been found that, if appropriate, in the benzene nucleus Dioxydiphenylmethanes substituted by alkyl and cycloalkyl groups by reaction corresponding phenols with formaldehyde at elevated temperature can be obtained, if the reaction is carried out in the presence of activated fuller's earth.

In this way, difficulties of a corrosion-related nature are avoided, and it is easy to separate the catalyst from the reaction products. In many cases, the method according to the invention also leads to considerably better ones Yields over previous methods.

For the method according to the invention are practically neutral, through an acid treatment activated bleaching earth suitable, as z. B. under the name »Tonsils« can be described in the literature (cf.

Ullmanns Encvclopadie der technischen Chemie, 3rd edition, Vol. 4, 1953, S.544, and Houben-Weyl, Methods of Organic Chemistry, 1955, Vol. 4, Part 2, S.149).

Example 1 In a mixture of 500 g of 2-cyclohexyl-4-cresol, pure, 450 cm3 of n-Lieptan and 50 g of active fuller's earth (as sold under the trade name »Tonsil« K 10 from from Südchemie AG., Munich) is 41.5 g of paraformaldehyde entered in 2 hours at 400 C. The temperature will rise within a further 6 hours slowly increased to 900 ° C. and then stirred at 900 ° C. for 16 hours. After adding a further 400 cmS of n-heptane, it is separated from the fuller's earth. then the solution is concentrated so that there are about 500 g of substance 400 cm of n-heptane. After standing overnight with good cooling, it is suctioned off.

The yield of 6,6'-bis (2-cyclohexyl-4-kresyl) methane is 92 ovo of theory and can be reduced by concentrating the mother liquor to 95 o / o of theory increase. F. 1320 C.

Example 2 In a 1 l three-necked flask equipped with a stirrer, dropping funnel, A reflux cooler and water separator is provided, a mixture of 188 g Phenol, 300 com n-heptane and 10 g of the same active fuller's earth as in the example 1 heated to near their boiling point. Then you let through the attached Dropping funnel, the drain pipe of which ends just below the liquid phase, in the course 105 g of 30 '/ above formaldehyde solution flow in over a period of 2 hours.

The mixture is heated (about 4 hours) until all of the water has separated out is. A pasty mass has settled on the floor. The decanting is still hot the n-heptane. The residue is then dissolved in the flask in 500 com of methanol Warming up in a water bath. The cooled solution is sucked off and the filter residue Digested again with hot methanol and filtered off with suction. The combined filtrates are freed from methanol and small traces of phenol by steam distillation. from the accruing Paste is decanted off the water and dried them in a flat layer in a vacuum drying cabinet at 50 to 1000 C. The resulting The mass consists of a mixture of isomeric dioxydiphenylmethanes. Molecular weight 200 to 220.0 H group content 17O / o. Yield 182 g (91% of theory).

When distilling, about a third can be achieved at bp 0.7 = 181 to 1820 C. distill off the NIasse.

Molecular weight 200, OH group content 17 17%. The rest gummed up under the effect of the high bath temperature on a hard, light-colored resin.

Example 3 216 g of p-cresol, 300 cc of n-heptane, 10 g of the same active Fuller's earth as in Example 1 and 105 g of commercially available 30% formalin processed as in example 2.

However, no paste is deposited in the course of the condensation. The n-heptane solution is filtered off while it is still hot in order to free it from the bleaching earth. The filter cake is washed out with hot n-heptane. The filtrates are combined concentrated and distilled with steam. After decanting the Water becomes the pasty residue dried at 1000 C in a vacuum drying cabinet. Yield of dioxyditolylmethanes: 202 g (91% of theory), molecular weight 220, 15% OH group content.

The residue, dissolved in 800 ccm hot n-heptane and cooled again, precipitated white crystals with a m.p. of 2020 C. Once from benzene recrystallized = melting point 2100 ° C., molecular weight 220, 14.9% 011 group content.

Claims (1)

PATENT CLAIM: Process for the production of, if necessary, in the benzene nucleus by alkyl and cycloalkyl groups substituted dioxy-diphenylmethaneu by Implementation of corresponding phenols with formaldehyde at elevated temperature, thereby characterized in that the reaction is carried out in the presence of activated fuller's earth. Documents considered: German Patent No. 689 600; U.S. Patent No. 2,572,141; Canadian Patent No. 489 103.