to the conjugate acid of an organic acid of the formula R3COOH, wherein R3 is a C3-C20 linear or branched alkyl. The secondary amine is reacted with an acylating agent of the formula R5C(O)OR6 where R5 is a C1-C20 linear or branched alkyl, R6 is H or a C1-C20 linear or branched alkyl, optionally with a catalytic amount of an amine, to provide an acylated amine of the formula:
The amidated amine of the formula (VII) is reacted with an acid chloride of the formula:
where R5 and R6 are as previously defined, in the presence of a base, preferably pyridine, to provide a polyol of the formula:
The polyol is separated from the reaction mixture, and then the polyol is treated with one or more aqueous acidic solvents to provide an aqueous acidic solution of the polyol having a pH of less than 4.0, preferably less than 3.0, more preferably less than 2.0. The polyol is preferably diluted with a non-aqueous solvent before being treated with the aqueous acidic solution to minimize the contamination of the solvent by the acidic solution.
Aqueous acidic solutions are prepared from aqueous acidic solvents and an acid. Examples of suitable aqueous acidic solvents include, but are not limited to, H2SO4, H3PO4, H3PO3, H3PO2, H2PO4, and mixtures thereof, and, more preferably, H2SO4 and H3PO4. Aqueous acidic solvents having a pH of from about 0.5 to about 1.5 are preferred. Aqueous acidic solutions having a pH of from about 1.0 to about 2.0 are particularly preferred. The concentrations of the aqueous acidic solutions are preferably from about 0.5% to about 20%, more preferably from about 2% to about 8%, by weight of the aqueous acidic solution.
The aqueous acidic solution and the polyol are reacted in the presence of an organic or an inorganic base. Any suitable base may be used, and the following bases are more preferred: N(CH3)3, morpholine, piperazine, piperidine, be359ba680
Related links:
Comments