CAJ | 학술논문

以醋酸锌(ZnAc2)为催化剂,甲醇(CH3OH)为醇解剂,采用在线红外光谱仪跟踪了聚对苯二甲酸乙二醇酯(PET)解聚反应过程中产物红外特征峰强度随时间的变化关系,研究了催化剂用量和反应温度对PET解聚过程的影响,并给出了可能的解聚机理.红外光谱跟踪结果表明,解聚过程中C-O,C=O基团的红外吸光强度随时间不断增强,解聚完成后吸光强度趋于定值.同时二者表现出相同的变化趋势,可以用其表征PET的解聚率.通过比较不同反应条件下的PET解聚速率发现,催化剂ZnAc2的适宜用量为PET质量的0.8%;提高反应温度可显著缩短PET解聚所需的时间,在190℃条件下,PET完全解聚仅用时15 min,具有良好的工业应用价值.PET解聚的主要产物是对苯二甲酸二甲酯(DMT)和乙二醇(EG),解聚过程中PET存在多种断链机制,产生不同的中间产物,可继续与甲醇发生酯交换反应生成DMT和EG.
이작산자(ZnAc2)위최화제,갑순(CH3OH)위순해제,채용재선홍외광보의근종료취대분이갑산을이순지(PET)해취반응과정중산물홍외특정봉강도수시간적변화관계,연구료최화제용량화반응온도대PET해취과정적영향,병급출료가능적해취궤리.홍외광보근종결과표명,해취과정중C-O,C=O기단적홍외흡광강도수시간불단증강,해취완성후흡광강도추우정치.동시이자표현출상동적변화추세,가이용기표정PET적해취솔.통과비교불동반응조건하적PET해취속솔발현,최화제ZnAc2적괄의용량위PET질량적0.8%;제고반응온도가현저축단PET해취소수적시간,재190℃조건하,PET완전해취부용시15 min,구유량호적공업응용개치.PET해취적주요산물시대분이갑산이갑지(DMT)화을이순(EG),해취과정중PET존재다충단련궤제,산생불동적중간산물,가계속여갑순발생지교환반응생성DMT화EG.
The process of polyethylene terephthalate (PET) alcoholysis was monitored by means of FT-IR spectrometer in situ. Using zinc acetate (ZnAc2) as the catalyst and methanol (CH3OH) as the alcoholysis reagent, the relationship between the IR peaks intensities of the reaction products and the reaction time was studied. Additionally, the influence of the used catalyst dosage and reaction temperature on the PET depolymerization process was investigated, and a possible mechanism of depolymerization was given. Infrared tracking results show that the infrared absorption intensities of C-O, C=O groups increase with the reaction time during the depolymerization process and tend to be respective constants after complete depolymerization. Based on this, the infrared absorption intensity of C-O, C=O groups can be used to characterize the PET depolymerization rate. It was found that the best used dosage of the catalyst ZnAc2 is 0.8%of the mass of PET. The time required for complete depolymerization can be greatly shortened when the reaction temperature is increased. At 190℃, PET can be depolymerized completely in only 15 min, it has a good industrial application value. There are several chain scission mechanisms in PET depolymerization process, the chain scissions of PET can produce different intermediates which can continually react with methanol to generate dimethyl terephthalate (DMT) and ethylene glycol (EG) through transesterification reaction with methanol.