Microwave driven trimethylsilylation of phenol-formaldehyde resins: extent of reactions determined by C-13 and Si-29 n.m.r.


Monsef-Mirzai P., MANAK H., MCWHINNIE W., SNAPE C., Sirkecioglu O. , ANDRESEN J.

FUEL, vol.77, no.5, pp.369-374, 1998 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 77 Issue: 5
  • Publication Date: 1998
  • Doi Number: 10.1016/s0016-2361(98)80026-4
  • Title of Journal : FUEL
  • Page Numbers: pp.369-374

Abstract

A phenol-formaldehyde (PF) resite resin and phenol:2,6-di-t-butylphenol-formaldehyde (DTBPF) co-resite were reacted under conditions of microwave heating with N-(trimethylsilyl)imidazole (TMSI). Low degrees of reaction were observed for the PF resin (19%) and for the DTBPF co-resite (0.3-0.4%) as examples of macromolecular systems with very limited porosity. C-13 SPE MAS n.m.r. was an effective method to determine the degree of silylation and C-13 CP MAS n.m.r. gave very similar results. When a different reagent mix (1:1:1 N,Obis(trimethylsilyl)acetamide: N(trimethylsilyl)imidazole:trimethylchlorosilane) was used both C-13 and Si-29 SPE n.m.r. were in agreement that 100% silylation of the OH groups had been achieved for the PF resin. Thus, with proper choice of conditions and reagents, microwave-driven silylation is a very effective method of OH analysis even for systems of significantly more limited porosity compared with coals. (C) 1998 Elsevier Science Ltd. All rights reserved.