带有膦酸基团的聚合物已被提议作为燃料电池应用在升高的操作温度下的无水质子传导膜。然而,膦酸聚合物的合成和对此类聚合物纳米结构的控制具有挑战性。在这里,我们报告了具有精确 26 和 48 个碳原子(C 26 PA 2和 C 48 PA 2)的膦酸封端的长链脂肪族材料的直接合成)。这些材料结合了单分散聚乙烯的结构能力和膦酸基团形成强氢键网络的能力。不存在酸酐形成,因此即使在升高的温度下也可避免缩合反应造成的载流子损失。在熔融温度 ( T m ) 以下,两种材料都表现出结晶聚乙烯主链和层状形态,其中平面膦酸聚集体对于 C 26 PA 2和 C 48 PA 2分别相距 29 和 55 埃。在T m之上,无定形聚乙烯 (PE) 链段与层状聚集体共存。这种现象在 C 中尤为明显26 PA 2并被确定为热致近晶液晶相。在这些条件下,观察到沿层法向的异常高的相关长度 (940 Å),证明了由膦酸基团形成的
带有膦酸基团的聚合物已被提议作为燃料电池应用在升高的操作温度下的无水质子传导膜。然而,膦酸聚合物的合成和对此类聚合物纳米结构的控制具有挑战性。在这里,我们报告了具有精确 26 和 48 个碳原子(C 26 PA 2和 C 48 PA 2)的膦酸封端的长链脂肪族材料的直接合成)。这些材料结合了单分散聚乙烯的结构能力和膦酸基团形成强氢键网络的能力。不存在酸酐形成,因此即使在升高的温度下也可避免缩合反应造成的载流子损失。在熔融温度 ( T m ) 以下,两种材料都表现出结晶聚乙烯主链和层状形态,其中平面膦酸聚集体对于 C 26 PA 2和 C 48 PA 2分别相距 29 和 55 埃。在T m之上,无定形聚乙烯 (PE) 链段与层状聚集体共存。这种现象在 C 中尤为明显26 PA 2并被确定为热致近晶液晶相。在这些条件下,观察到沿层法向的异常高的相关长度 (940 Å),证明了由膦酸基团形成的
申请人:The United States of America as represented by the Secretary of Agriculture
公开号:US07534917B1
公开(公告)日:2009-05-19
A method of producing dicarboxylic acids (e.g., α,ω dicarboxylic acids) by reacting a compound having a terminal COOH (e.g., unsaturated fatty acid such as oleic acid) and containing at least one carbon-carbon double bond with a second generation Grubbs catalyst in the absence of solvent to produce dicarboxylic acids. The method is conducted in an inert atmosphere (e.g., argon, nitrogen). The process also works well with mixed unsaturated fatty acids obtained from soybean, rapeseed, tall, and linseed oils.
double bond of the α,ω‐dicarboxylic fatty acid self‐metathesisproducts is shifted selectively to the statistically much‐disfavored α,β‐position in a catalytic dynamic isomerizing crystallization approach. “Chain doubling” by a subsequent catalytic olefinmetathesis step, which overcomes the low reactivity of this substrates by using waste internal olefins as recyclable co‐reagents, yields ultra‐long‐chain
从常见的单不饱和脂肪酸开始,揭示了一种策略,该策略通过两个可扩展的催化步骤序列提供超长的脂肪族α,ω-双官能结构单元,实际上使起始原料的链长增加了一倍。在催化动态异构化结晶方法中,α,ω-二羧酸脂肪酸自复分解产物的中心双键选择性地转移到统计学上不利的α,β-位置。通过随后的催化烯烃复分解步骤实现“链加倍”,该步骤通过使用废弃的内部烯烃作为可回收的共试剂克服了这种底物的低反应性,从而产生了具有精确链长的超长链α,ω-双官能结构单元,如C 48所示链。这些结构的独特性体现在由这些遥螯单体产生的脂肪族聚酯的无与伦比的熔点(T m = 120°C),以及它们自组装成聚乙烯类单晶的过程。
Metathesis of unsaturated fatty acids: Synthesis of long-chain unsaturated-α,ω-dicarboxylic acids
作者:Helen L. Ngo、Kerby Jones、Thomas A. Foglia
DOI:10.1007/s11746-006-1249-0
日期:2006.7
AbstractThe self‐metathesis of readily available monounsaturated FA has the potential of being an important pathway for the synthesis of symmetrical long‐chain unsaturated‐α,ω‐dicarboxylic acids (C18−C26). Previous studies on the self‐metathesis of monounsaturated FA esters using ruthenium catalysts in solution, however, suffered from low conversions as a result of the thermodynamic control of the reaction. We have found that the second‐generation Grubbs catalyst can effectively catalyze the solvent‐free self‐metathesis of monounsaturated FA of varying purity (from 90 to 99%) to afford two important products—monounsaturated dicarboxylic acids and hydrocarbons—in very high molar conversions (>80%). This solvent‐free self‐metathesis reaction also works for monounsaturated FA containing additional functional groups. Reactions were conducted at catalyst loadings as low as 0.005 mol%, and turnover numbers as high as 10,800 could be obtained. This discovery represents an attractive approach to the large‐scale production of useful monounsaturated‐α,ω‐dicarboxylic acids and long‐chain unsaturated hydrocarbons by means of this solvent‐free ruthenium‐catalyzed self‐metathesis of readily available monounsaturated FA.