Bioderived Muconates by Cross‐Metathesis and Their Conversion into Terephthalates,ChemSusChem

当前位置： X-MOL 学术 › ChemSusChem › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Bioderived Muconates by Cross‐Metathesis and Their Conversion into Terephthalates
ChemSusChem ( IF 7.5 ) Pub Date : 2018-01-29 , DOI: 10.1002/cssc.201701874
Erisa Saraçi _{1,

2} , Lan Wang _{1,

3} , Klaus H. Theopold _{1,

3} , Raul F. Lobo _{1,

2}

Affiliation

Polyethylene terephthalate that is 100 % bioderived is in high demand in the market guided by the ever‐more exigent sustainability regulations with the challenge of producing renewable terephthalic acid remaining. Renewable terephthalic acid or its precursors can be obtained by Diels–Alder cycloaddition and further dehydrogenation of biomass‐derived muconic acid. The cis,cis isomer of the dicarboxylic acid is typically synthesized by fermentation with genetically modified microorganisms, a process that requires complex separations to obtain a high yield of the pure product. Furthermore, the cis isomer has to be transformed into the trans,trans form and has to be esterified before it is suitable for terephthalate synthesis. To overcome these challenges, we investigated the synthesis of dialkyl muconates by cross‐metathesis. The Ru‐catalyzed cross‐coupling of sorbates with acrylates, which can be bioderived, proceeded selectively to yield diester muconates in up to 41 % yield by using very low catalyst amounts (0.5–3.0 mol %) and no solvent. In the optimized procedure, the muconate precipitated as a solid and was easily recovered from the reaction medium. Analysis by GC–MS and NMR spectroscopy showed that this method delivered exclusively the trans,trans isomer of dimethyl muconate. The Diels–Alder reaction of dimethyl muconate with ethylene was studied in various solvents to obtain 1,4‐bis(carbomethoxy)cyclohexene. The cycloaddition proceeded with very high conversions (77–100 %) and yields (70–98 %) in all of the solvents investigated, and methanol and tetrahydrofuran were the best choices. Next, the aromatization of 1,4‐bis(carbomethoxy)cyclohexene to dimethyl terephthalate over a Pd/C catalyst resulted in up to 70 % yield in tetrahydrofuran under an air atmosphere. Owing to the high yield of the reaction of dimethyl muconate to 1,4‐bis(carbomethoxy)cyclohexene, no separation step was needed before the aromatization. This is the first time that cross‐metathesis is used to produce bioderived trans,trans‐muconates as precursors to renewable terephthalates, important building blocks in the polymer industry.

中文翻译：

跨复分解生物衍生的粘液及其转化为对苯二甲酸酯

市场上对100％生物衍生的聚对苯二甲酸乙二酯的需求越来越高，这是在日益严格的可持续性法规的指导下进行的，同时还面临着生产可再生对苯二甲酸的挑战。可通过Diels-Alder环加成反应以及生物质衍生的粘康酸进一步脱氢制得可再生对苯二甲酸或其前体。二羧酸的顺式，顺式异构体通常是通过用转基因微生物发酵而合成的，该过程需要复杂的分离以获得高产率的纯产物。此外，顺式异构体必须转化为反式，反式形式，必须先酯化才能适合对苯二甲酸酯合成。为了克服这些挑战，我们研究了交叉复分解法合成粘康酸二烷基酯的方法。Ru催化的山梨酸酯与丙烯酸酯的交叉偶联（可生物衍生）通过使用极低的催化剂量（0.5–3.0 mol％）且不使用溶剂，选择性地进行，以最高41％的收率生产二酯粘液。在优化的过程中，粘液以固体形式沉淀出来，很容易从反应介质中回收。通过GC-MS和NMR光谱分析表明，该方法专门提供了反式，反式粘康酸二甲酯的异构体。在各种溶剂中研究了癸二酸二甲酯与乙烯的Diels-Alder反应，得到1,4-双（羰甲氧基）环己烯。在所研究的所有溶剂中，环加成反应均具有很高的转化率（77–100％）和产率（70–98％），甲醇和四氢呋喃是最佳选择。接下来，在空气气氛下，在Pd / C催化剂上将1,4-双（羰基甲氧基）环己烯芳构化为对苯二甲酸二甲酯，在四氢呋喃中的收率高达70％。由于粘康酸二甲酯与1,4-双（羰甲氧基）环己烯的反应收率高，因此在芳构化之前不需要分离步骤。这是交叉复分解首次用于生产生物衍生的反式，反式粘康酸酯是可再生对苯二甲酸酯的前体，可再生对苯二甲酸酯是聚合物行业的重要组成部分。

更新日期：2018-01-29

点击分享查看原文

点击收藏

公开下载

阅读更多本刊最新论文本刊介绍/投稿指南11