Improvement in the determination of p-Toluic Acid and 4-Carboxybenzaldehyde in Purified Terephthalic

• 作 者: Yidan Guo Yuhong Zhang Haiqing Zhuang Chuan Wang
• 机 构: Shanghai Research Institute of Petrochemical Technology, China Petrochemical Group, Shanghai 201208,
• 出 处: 第2届大连国际色谱学术报告会、第37届国际高效液相色谱及相关技术会议、第18届全国色谱学术报告会
• 发表日期: 2011年3期
• 关键词: PTA p-Toluic Acid 4-Carboxybenzaldehyde HPLC

　　Purified terephthalic acid (PTA), as an important raw material, is primarily used for the production of polyester PET (Polyethylene terephthalate), polybutyl terephthalate(PBT) and etc.The contents of two major impurities in PTA, 4-CBA and p-Toluic acid, need to be well controlled since these impurities are detrimental to the PTAs following producing process.The current HPLC methods for the determination of the impurities in PTA have some disadvantages including a short column life and a long run time.In this paper, an improved HPLC method is developed.A smaller-diameter SHIMADZU Shim-Pack WAX column was employed with the mobile phase of 0.08 mol/L NH4H2PO4 + 10% methonal.A Diol precolumn was also used.As a result, the efficiency of column was improved and the column life was prolonged significantly.A 20 times duplicate runs of PTA and QTA samples indicated the good repeatability of the method (in Table 1).The study also indicated that an improved sensitivity could be obtained by detecting each impurity at its maximum absorption wavelength instead of at 254nm simply.