62016-48-2Relevant academic research and scientific papers
Direct methylation of primary and secondary alcohols by trimethyl phosphate to prepare pure alkyl methyl ethers
Van Dyke Tiers, George
, p. 1223 - 1233 (2007/10/03)
Primary and secondary alcohols and diols react autocatalytically with trimelhyl phosphate plus small amounts of polyphosphoric acid at 185°C to give the corresponding methyl ethers. High purity and good yields are achieved when the ether is distilled from the reaction mixture as it is formed. By controlled addition even low-boiling alcohols can be methylated successfully. The reaction mechanism is undetermined. Peroxide formation in ethers is inhibited by storage over 10 molal KOH. Pure isotropic optical crystals are used for refractometer calibration. Improved physical property and NMR data (1H and 13C) are reported for thirteen methyl ethers. Simple two-point linear extrapolation of NMR shifts (especially 13C) to infinite dilution produces highly reproducible δ°-values (to 0.01 ppm or better) which uniquely characterize a molecule even when unidentified and/or not isolated from a mixture. This capability appears not to have been recognized in the literature. Acta Chemica Scandinavica 1998.
Acid-induced 13C Nuclear Magnetic Resonance Chemical Shift Changes of Ether and Ester Carbon Atoms
Begtrup, Mikael
, p. 1609 - 1618 (2007/10/02)
13C N.m.r. chemical shifts of ehters dissolved in tetrachloromethane are displaced on addition of trifluoroacetic acid.The displacements result from independent interactions of the acid with the substrate oxygen atoms and alkyl residues.The structure-dependent and stereoselective shift changes are useful for signal assignments, structure determination, conformational analysis, assessment of the distribution of rapidly interconverting conformers of esters, and estimation of the relative basicity of ethers.
