发烟硫酸磺化法合成间苯二甲酸-5-磺酸的新工艺

以间苯二甲酸(IPA)、65%发烟硫酸为原料,经磺化反应制备间苯二甲酸-5-磺酸(SIPA)。采用加压梯度升温反应与减压反应结合控制反应过程,加压(表压0.01~0.015MPa)条件下分120~130℃、135~145℃、150~160℃3个阶段升温反应,减压(真空度0.05~0.08MPa)条件下在160~170℃反应。考察了磺化反应各个因素的影响,优化了工艺条件,建立了产品的分析检测方法。结果表明,磺化反应的最佳条件为:物料配比m(IPA)∶m(65%SO3·H2SO4)=1.186∶1,表压0.01MPa下最高反应温度160℃,真空度0.06MPa下最高反应温度170℃,总反应时间7.0h,产品收率98.5%以上,纯度98.8%以上。新工艺比现有生产工艺最高反应温度降低30℃,反应时间缩短2h,发烟硫酸用量减少5%。

NEW PROCESS FOR SYNTHESIS OF SIPA BY SULFONATION OF FUMING SULFURIC ACID

Through sulfonation, m-Sulfoisophthalic acid(SIPA) was synthesized by using isophthalic acid(IPA) and 65% fuming sulfuric acid. The reaction process is controlled by the combination of pressure gradient heating reaction and pressure reduction reaction. Under the condition of pressure (gage pressure was 0.01-0.015 MPa), the reaction temperature stage were 120-130 ℃, 135-145 ℃, 150-160 ℃. Under the condition of decompression (vacuum degree was 0.05 0.08 MPa), the reaction temperature was between 160 ℃ to 170 ℃. The optimized process for preparation of SIPA was researched and the determination method of intermediate was established. The results showed that the appropriate mass ratio of IPA to 65% fuming sulfuric acid, the maximum reaction temperature under 0.01 MPa(gage pressure), the highest reaction temperature under vacuum 0.06 MPa and total sulfonation time were 1.186∶1, 160 ℃, 170 ℃ and 7.0 h. Respectively, the IPA was completely converted into SIPA. Which the yield and purity were above 98.5% and 98.8%. Compared with the existing production process, the highest reaction temperature lessened 30 ℃, the reaction time shortened more than two hours, fuming sulfuric acid consumption reduced 5%.