Synthesis of Alkoxylated Phenolic Resins Containing an Acetyl Group and Their Functionalization by Grignard Reaction

Abstract

We successfully synthesized acetyl group-containing phenolic resins as novel reactive polymers. The addition-condensation of 2,4,6-trimethoxyacetophenone (1) with an equimolar amount of formaldehyde catalyzed by 12 mol/L HCl aq. proceeded homogeneously without side reactions to give polymer 3 (M n 4800, M w =M n 1.3) in 32% yield. The FT-IR, 1 H NMR and 13 C NMR spectra of 3 revealed that it had arylene-methylene units on the polymer backbones. The terpolymerization from 1, 1,3,5-trimethoxybenzene (2) and formaldehyde was also carried out. When the feed ratio of 1 to 2 was 1:1, the content of 1 in the obtained polymer, 4, was found to be 25% by the 1 H NMR spectrum; hence, the reactivity of 1 was lower than that of 2. The reactions of 4 with Grignard reagents were carried out to evaluate the reactivity of acetyl groups in the obtained polymers. Their reactions proceeded at some parts of acetyl groups, so 4 can be applied as novel reactive phenolic resins. From thermogravimetric analyses, thermal stabilities of the functionalized polymers (6a-6d) are similar to that of 4, so it is expected that 4 have characters not only of the phenolic resins but also of the reactive polymers.

Synthesis of a Formyl Group-Containing Reactive Novolac

“…The synthesis of a reactive trimethoxybenzene novolac having acetyl groups and their polymer reaction with a Grignard reagent are described in a separate paper. 16 …”

Development of lignin as a transparent resin: evaluation of thermal and optical properties of alkoxylated lignophenols

“…Therefore, to develop a high-performance LP, it is necessary to modify these functional groups. Previously, we demonstrated that phenolic resins prepared from phenol derivatives containing protected (alkoxylated) hydroxyl groups [13][14][15][16] exhibit higher thermostability; for example, it was demonstrated that 10% loss in weight (T d10 ) of alkoxylated-naphthalene-based resin occurs at a temperature greater than 400 1C. Further, alkoxylated-phenol-derivative-based phenolic resins exhibited good filmforming abilities and processabilities.…”

Direct synthesis of functional novolacs and their polymer reactions

“…2,23 From this viewpoint, we have synthesized a wide variety of aromatic polymers from alkoxylated phenol derivatives such as anisole, phenethol and diphenyl ether by a method similar to acid-catalyzed phenol-formaldehyde condensation. 2,[23][24][25][26][27][28][29][30][31][32][33] The obtained polymers exhibit good solubility in organic solvents and they are more resistant to heat and oxidation than are phenolic novolacs. Furthermore, using hydroxyl-group-functionalized phenol derivatives, a functional novolac can be prepared by a one-step procedure.…”

“…[34][35][36][37][38][39][40][41][42][43][44][45][46] We have already reported the synthesis of reactive novolacs having a variety of functional groups such as formyl, 31 acetyl 32 and hydroxymethyl groups. 33 The development of such novel reactive novolacs can lead to novolacs finding significantly increased applications.…”