K_(2)CO_(3)催化醇解酯交换再生DMT的制备及减压升华提纯  

Preparation of recycled DMT by K_(2)CO_(3) catalytic glycolysis-transesterification and its purification by decompression sublimation method

作　　者：李小军 官军 吕维扬 姚玉元[1,2] LI Xiaojun;GUAN Jun;Lü Weiyang;YAO Yuyuan(National Engineering Lab for Textile Fiber Materials and Processing Technology,Zhejiang Sci-Tech University,Hangzhou 310018,China;Zhejiang Provincial Innovation Center of Advanced Textile Technology,Shaoxing 312030,China;Zhejiang Jiaren New Material Co.,Ltd.,Shaoxing 312000,China)

机构地区：[1]浙江理工大学纺织纤维材料与加工技术国家地方联合工程实验室,杭州310018 [2]浙江省现代纺织技术创新中心,浙江绍兴312030 [3]浙江佳人新材料有限公司,浙江绍兴312000

出　　处：《现代纺织技术》2025年第2期59-66,共8页Advanced Textile Technology

基　　金：浙江省“尖兵”“领雁”研发攻关计划项目(2022C01197,2023C01203)。

摘　　要：在醇解-酯交换法回收废旧聚酯纺织品过程中,重金属盐类醇解催化剂易引发环境污染,且强碱性酯交换催化剂NaOH易引起设备腐蚀。为了改善该问题,采用K_(2)CO_(3)催化醇解废旧聚酯纺织品制得醇解产物,以K_(2)CO_(3)为酯交换反应催化剂将醇解产物转化为再生对苯二甲酸二甲酯(DMT),通过单因素实验协同响应面法统计分析,系统研究了酯交换反应时间、甲醇与醇解产物投料比、催化剂K_(2)CO_(3)添加量及其交互作用对再生DMT收率的影响,获得最佳反应参数组合,并采用减压升华法对含杂再生DMT进行提纯。结果表明:醇解产物主要成分为对苯二甲酸双羟乙酯(BHET),伴含微量BHET低聚体及对苯二甲酸单羟乙酯;酯交换最佳反应参数为反应温度70℃、反应时间118 min、甲醇与醇解产物质量投料比2.13∶1、K_(2)CO_(3)添加量为醇解产物质量的0.94%,该工艺条件下再生DMT实际收率为88.50%;经3次减压升华提纯,再生DMT中2-羟乙基甲基对苯二甲酸酯、对苯二甲酸单甲酯和间苯二甲酸二甲酯等杂质均得到有效去除,再生DMT纯度高达99.89%。As the application fields of polyester fibers continue to expand and production capacity continues to increase,the cumulative amount of waste polyester textiles is also growing steadily.A large amount of waste polyester textiles are landfilled or incinerated,causing serious waste of resources and environmental pollution.The glycolysis method,which can depolymerize waste polyester into bis(hydroxyethyl)terephthalate(BHET),has mild reaction conditions,good safety and high product yield,but its traditional depolymerization catalysts are based on heavy metal salts such as zinc,manganese,cobalt,antimony and other heavy metal salts.Although their catalytic effects are significant,they can easily cause heavy metal pollution.Furthermore,waste polyester textiles come from a wide range of sources and often contain impurities such as cotton,oil stains and dyes.Moreover,the product BHET is prone to polycondensation under high temperature conditions,makeing it extremely difficult to remove impurities and decolorize,thus limiting this method to the treatment of pure bottle flakes and films and hindering its application in the recycling of waste polyester textiles.Utilizing the inherent advantages of the depolymerization system of the glycolysis method,the waste polyester is depolymerized to produce glycolysis products,which can then be esterified with methanol to produce dimethyl terephthalate(DMT),one of the most promising process routes at present.However,the traditional strong alkaline transesterification catalyst NaOH is easy to cause equipment corrosion,and the conventional recrystallization method of purification is time-consuming and energy-intensive,and consumes a large amount of methanol consumption.In this way,the quality of DMT is difficult to reach high purity grade.Based on the above,glycolysis products of waste polyester textiles were prepared by using K_(2)CO_(3) as catalyst,and then K_(2)CO_(3) was used as catalyst for methanol transesterification to transform the glycolysis products into recycled DMT.The recyc

关 键 词：废旧聚酯 醇解 酯交换 再生DMT 减压升华 

分 类 号：TQ342.21[化学工程—化纤工业]