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4114754 
Journal Article 
Direct methylation of primary and secondary alcohols by trimethyl phosphate to prepare pure alkyl methyl ethers 
Tiers, GV 
1998 
Yes 
Acta Chemica Scandinavica
ISSN: 0904-213X
EISSN: 1902-3103 
52 
10 
1223-1233 
WOS:000076371600007 
Primary and secondary alcohols and diols react autocatalytically with trimethyl phosphate plus small amounts of polyphosphoric acid at 185 degrees 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 (H-1 and C-13) are reported for thirteen methyl ethers. Simple two-point linear extrapolation of NMR shifts (especially C-13) to infinite dilution produces highly reproducible delta degrees-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.