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Santhappa, Muchi (1948) Factors determining the formation of phenol-formaldehyde resins from tetramethyl phenols and methyl ethers of some substituted phenols. Doctoral thesis, Northern Polytechnic.
A study of the interaction between tetra-methyl phenols and fermaldehyde was considered desirable, firstly to minimise the complexity of the resinification reaction between phenol and formaldehyde by yielding crystalline products, secondly to ascertain the part taken by the phenolic hydroxyl group during the hardening of resites, and thirdly to confirm the postulates of the theory of functionality. By the application of the Fittig reaction to the dibromo-derivatives of the methyl ether of 3-5, Xylenol, and by subsequent demethylation, the synthesis of Prehnitenol - was affected.
The methyl ethers of phenol, o- and p-cresols, 3,5-, 3,4-, and 2,6- xylenols did not react with formaldehyde in alcoholic and acetone solutions, even at 80-90° in the presence of sodium hydroxide and pyridine as catalysts.
Some mono- and dimethylol compounds of methyl ethers of phenols were synthesised. Progress of resininfication of these resoles was followed by thermal condensation experiments in nitrogen, quantities of water, formaldehyde being determined. Saponification of the resins by hydrogen bromide was carried out.
Condensation of the methyl ethers of phenols with formaldehyde in glacial acetic acid, concentrated sulphuric acid being used as catalyst, yielded crystalline dimethoxydiphenyl-methane derivatives in some cases at 50-60° and low condensed novolak resins at higher temperatures.
Evidence for the structure of novolak resins as composed of mixtures of polymethylene chains was adduced from the novolaks obtained from methyl ethers of phenols. Evidence that the methylol compound is the first product, both in the acid and alkaline catalysed rections, was obtained. That the phenolic hydroxyl group and methylene group may function as cross linking agents in the hardening reaction was indicated by indirect evidence.
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