对羟基苯乙酸的合成

Synthesis of 4-hydroxyphenyl acetic acid

以乙醛酸和苯酚为起始原料,在碱性溶液中经缩合反应得到对羟基扁桃酸钠,进一步经亚硫酸氢钠还原得到对羟基苯乙酸.目标产物经液相色谱进行了鉴定,结果表明,对羟基苯乙酸质量分数97.5%,纯度99.65%.研究发现:缩合反应中乙醛酸∶苯酚∶氢氧化钠的物质的量的比为1∶1.5∶2.5时,对羟基扁桃酸钠的收率可达85%;还原反应优化工艺:n(对羟基扁桃酸钠)∶n(亚硫酸氢钠)=1∶1.1,反应温度100℃,总压0.10～0.15MPa.该法原料来源广泛,工艺简单,成本低,产品质量好并且绿色环保,具有良好的工业前景.

The target compound was obtained by condensation and reduction from phenol, 50% glyoxylic acid, and sodium bisulfite. The mass fraction and purity of 4-hydroxyphenyl acetic acid, determined by HPLC, were 97.5% and 99.65% respectively. The yield of sodium-4-hydroxyphenyl acetic acid reached 85% when the molar ratio of glyoxylic acid, phenol and sodium hydroxide was 1 ： 1.5 .： 2.5. The reductive reaction was performed at 100℃, under the pressure of 0. 10-0. 15 MPa, at 1 ： 1.1 molar ratios of sodium-4- hydroxymandalate monohydrate to sodium bisulfite. This method has a better industrial prospects by its extensive raw material, simple process, lower cost, better product quality and environmental protection.