¹³C‐NMR‐Untersuchungen an Phenol‐Formaldehyd‐Harzen. 3. Zur Bildung von Dimethylenetherstrukturen in Phenol‐Resolen

Abstract

Bei der Umsetzung von Phenol und Formaldehyd bilden sich auch in Gegenwart basischer Katalysatoren Dimethylenetherstrukturen. Reaktionstemperaturen unter 8OoC sowie ein Uberschud an Formaldehyd begunstigen das Entstehen der Ether. Unter RuckfluDbedingungen (98 "C) und mit aquimolaren Phenol-Formaldehyd-Anteilen konnten nur in Magnesiumoxid-Resolen Ether nachgewiesen werden.BccJceaoeanue rJ5enoJco-gfiopMcaJcaaezuaHblz CMOJZ Merno3ofi H M P 13C. Yacmb I I I . 0 6 06pa3oeanuu 3u~emunenarJ5up-nbix cmpyxmyp e peaonax npH peaHqkiH @eHOJIa C @OpMaJIbEerHAOM 06pa3YH)TCR AHMeTHJIeH3@HpHbIe MOCTHKIl AaHW B IIpHCyTCTBIlK OCHOBHHX KaTaJIH3aTOpOB. TeMIIepaTypa peaKqHM HHXe 80 " c H 1136bITOK @OpMaJIbAerAAa CIIOCO6CTByH)T 06pa30BaHH10 3@11pOB. B YCJIOBHFIX @JIerMhI (98OC) I4 IIpA EIKBHMOJIRPHHX COOTHOILleHARX PeareHTOB 3@11pbI 6~~1 1 1 13C-NMR investigations with phenol-formaldehyde resins. 3. The formation of dimethylene ether structures in phenol-resolsIn reacting phenol and formaldehyde in the presence of basic catalysts also dimethylene ether structures are formed. The formation of ethers is favored by reaction temperatures below 80°C and by an excess of formaldehyde. Under reflux (98OC) and with a phenol to formaldehyde ratio of 1:l ether bridges were"found to be formed only with magnesium oxide as catalyst.

Anisotropic high-surface-area carbon aerogels

“…In basic conditions, the formation of ether bridges is favored by a reaction temperature below 80°C and by an excess of formaldehyde [15]. Also, lowering the temperature increases the dimethylether concentration.…”

“…The mechanism of polymerization and cross-linking of phenol or resorcinol-formaldehyde in different conditions (yielding resins or gels) has already being investigated [14,15]. In aqueous solvent, water dissociates the catalyst.…”

Effect of F/P and OH/P molar ratios and condensation viscosity on the structure of phenol‐formaldehyde resol resins for overlays—A statistical study

“…In this study, the effects of F/P molar ratio, OH/P molar ratio, and condensation viscosity on the chemical structures, molecular weights, and reactivity of the phenol‐formaldehyde resol resins were studied by 13 C‐NMR spectroscopy,1–9, 20–44 gel permeation chromatography,1–7, 10, 43–49 and differential scanning calorimetry1–4, 11, 19, 20, 44–54 utilizing a two‐level full factorial experimental design.…”