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首页> 外文期刊>RSC Advances >Bismuth subsalicylate, a low-toxicity catalyst for the ring-opening polymerization (ROP) of l-lactide (l-LA) with aliphatic diol initiators: synthesis, characterization, and mechanism of initiation
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Bismuth subsalicylate, a low-toxicity catalyst for the ring-opening polymerization (ROP) of l-lactide (l-LA) with aliphatic diol initiators: synthesis, characterization, and mechanism of initiation

机译：具有脂族二醇引发剂的L-丙交酯（L-LA）的开环聚合（ROP）的低毒性催化剂，具有脂族二醇引发剂：合成，表征和起始机理

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The ring-opening polymerization (ROP) of L -lactide ( L -LA) was induced by the catalytic action of bismuth subsalicylate (BiSS) using linear aliphatic diols [HO(CH _(2) ) _( n ) OH, where n = 2, 3, 4, 5, 6, and 8] as initiators and chain transfer agents. The theoretical and experimental degree of polymerization (DP) in all samples of α,ω-hydroxy telechelic poly( L -lactide) (HOPLLAOH) had a good agreement in all samples, an effect attributed to the interaction of BiSS with HO(CH _(2) ) _( n ) OH inducing a transfer reaction. HOPLLAOH was synthesized and characterized by a range of analytical techniques, confirming the insertion of methylene groups from the initiator into the main chain of the polyester. The glass-transition temperature ( T _(g) ) of HOPLLAOH was found to be proportional to the number of methylene groups present in the diol. Various parameters regarding the ROP of L -LA were studied, such as temperature, time of reaction, amount of catalyst, and the nature of the diols. A kinetic study of the reaction allowed the determination of the rate constants ( k ) and activation energy ( E _(a) ). A mechanism of initiation is proposed based on a computational study using density functional theory (DFT), evidencing the role of the alkyl diol as an initiator, producing an alkoxide (Bi–OROH). This species then acts as a nucleophile, attacking the carbonyl group, inducing its insertion, and ultimately completing the ring-opening of L -LA.
机译：使用线性脂族二醇催化作用（Biss）的催化作用诱导L-阶L-Lactide（L -LA）的开环聚合（ROP）[HO（CH _（2））_（n）哦，其中n = 2,3,4,5,6和8]作为引发剂和链转移剂。在所有样品中α，ω-羟基左右的α，ω-羟基左右+ +阶层）（Hopllaoh）的所有样品中的聚合（DP）具有良好的一致性，这一效果归因于BISS与HO的互动（CH _ （2））_（n）oh诱导转移反应。 HopllaoH被合成并表征了一系列分析技术，证实将亚甲基从引发剂插入聚酯的主链中。发现啤酒花的玻璃化转变温度（T _（g））与二醇中存在的亚甲基数量成比例。研究了关于L -LA ROP的各种参数，例如温度，反应时间，催化剂的量，以及二醇的性质。反应的动力学研究允许测定速率常数（k）和活化能量（E _（a））。基于使用密度泛函理论（DFT）的计算研究提出了启动机制，证明烷基二醇作为引发剂的作用，产生醇盐（Bi-OOH）。然后，该物种用作亲核试剂，攻击羰基，诱导其插入，并最终完成L-LA的开环。

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