A method for the preparation of Ethyl 2-methylnicotinate, as follows:
(1) 2.0 mol of 1,1,3,3-tetramethoxypropane was added into a reactor at room temperature, 2.5 mol of hydrochloric acid at a mass concentration of 20% was added with stirring, and the reaction was carried out at a controlled temperature of 40 C. for 4 hours; the 2.5 mol refers to the molar amount of HCl in the hydrochloric acid, and the following is the same;
( 2) adding 1 mol of -aminocrotonic acid methyl ester, 6 mol of methanol to the reactor, controlling the reaction temperature at 50C, and reacting for 6 hours;
wherein the molar ratio of -aminocrotonic acid methyl ester, 1,1,3,3-tetramethoxypropane, hydrochloric acid, and methanol was 1.0:2.0:2.5:6.0;
(3) reducing pressure and concentrating the above reaction solution (3)Concentrate the above reaction solution under reduced pressure, neutralize the concentrated solution with 10% aqueous sodium hydroxide solution to the system pH=5.0, add 5 times the mass of -aminocrotonic acid methyl ester of ethyl acetate to the system, extract the fractional phase, add 4 times the mass of -aminocrotonic acid methyl ester of water to the organic phase, wash the fractional phase, concentrate the organic phase, and then continue to distil with a small rotary-vane vacuum pump to collect the fractions, to obtain the liquid of 2-methyl nicotinic acid methyl ester 105.9 g , with a yield of 70.1% and a purity of 98.45%.
