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Improving photocatalytic free radical polymerization with hydrochloric acid†
Catalysis Science & Technology ( IF 4.4 ) Pub Date : 2019-05-22 00:00:00 , DOI: 10.1039/c9cy00199a Yulan Zhou 1, 2, 3, 4, 5 , Wanfeng Liao 1, 2, 3, 4, 5 , Xiuyuan Ni 1, 2, 3, 4, 5
Catalysis Science & Technology ( IF 4.4 ) Pub Date : 2019-05-22 00:00:00 , DOI: 10.1039/c9cy00199a Yulan Zhou 1, 2, 3, 4, 5 , Wanfeng Liao 1, 2, 3, 4, 5 , Xiuyuan Ni 1, 2, 3, 4, 5
Affiliation
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In this work, the photocatalytic free radical polymerization of vinyl acetate (VAc) in aqueous medium was studied by using titanium dioxide nanoparticles as a photoinitiator, and we found the reaction rates and polymer yields of this aqueous photopolymerization to be sensitively influenced by hydrochloric acid (HCl). The chemical structures and molecular weights of the synthesized polyvinyl acetate were characterized by nuclear magnetic resonance (NMR) and gel permeation chromatography. Kinetic studies were carried out to correlate the reaction characteristics with HCl concentration. An efficient photocatalytic free radical polymerization in aqueous medium was thus achieved with the monomer conversion of VAc as high as 89.9%. The electron spin resonance (ESR) results show that OH˙ radicals are generated in the reaction system under UV irradiation, and the intensity of the OH˙ radical signal becomes stronger when HCl is added. Moreover, we used deuterium chloride (DCl) to identify the gaseous products of this photocatalytic reaction. As proved by the isotope analysis and gas chromatograph-mass spectrometry, HD and D2 were generated markedly. The 2H-NMR spectrum revealed that DCl had participated in the photocatalytic initiation reactions. According to these results, the initiation reactions were analyzed in terms of the reduction reactions concerning H+ and D+.
中文翻译：
用盐酸改善光催化自由基聚合†
在这项工作中，使用二氧化钛纳米粒子作为光引发剂研究了醋酸乙烯酯（VAc）在水性介质中的光催化自由基聚合，我们发现这种水性光聚合的反应速率和聚合物收率受到盐酸的敏感影响（ HCl）。通过核磁共振（NMR）和凝胶渗透色谱对合成的聚乙酸乙烯酯的化学结构和分子量进行了表征。进行了动力学研究，以使反应特性与HCl浓度相关。因此，通过VAc的单体转化率高达89.9％，实现了在水性介质中的有效的光催化自由基聚合。电子自旋共振（ESR）结果表明，在紫外线辐射下，反应体系中会生成OH˙自由基，当加入HCl时，OH +自由基信号的强度变强。此外，我们使用了氯化氘（DCl）来确定这种光催化反应的气态产物。同位素分析和气相色谱-质谱法证明了HD和D明显产生了2个。所述2 H-NMR谱表明，DCl的参加了光催化引发反应。根据这些结果，根据涉及H +和D +的还原反应来分析引发反应。
更新日期：2019-05-22
中文翻译：
用盐酸改善光催化自由基聚合†
在这项工作中，使用二氧化钛纳米粒子作为光引发剂研究了醋酸乙烯酯（VAc）在水性介质中的光催化自由基聚合，我们发现这种水性光聚合的反应速率和聚合物收率受到盐酸的敏感影响（ HCl）。通过核磁共振（NMR）和凝胶渗透色谱对合成的聚乙酸乙烯酯的化学结构和分子量进行了表征。进行了动力学研究，以使反应特性与HCl浓度相关。因此，通过VAc的单体转化率高达89.9％，实现了在水性介质中的有效的光催化自由基聚合。电子自旋共振（ESR）结果表明，在紫外线辐射下，反应体系中会生成OH˙自由基，当加入HCl时，OH +自由基信号的强度变强。此外，我们使用了氯化氘（DCl）来确定这种光催化反应的气态产物。同位素分析和气相色谱-质谱法证明了HD和D明显产生了2个。所述2 H-NMR谱表明，DCl的参加了光催化引发反应。根据这些结果，根据涉及H +和D +的还原反应来分析引发反应。
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