818-58-6Relevant articles and documents
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Benkeser,R.A. et al.
, p. 132 - 137 (1969)
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Palladium-Catalyzed Methoxycarbonylation of 1,3-Butadiene to Methyl-3-Pentenoate: Introduction of a Continuous Process
Han, Li-Jun,Ma, Shuang-Shuang,Rao, Chong-Shun,Sheng, Gui-Yang,Xu, Bao-Hua,Zhang, Jun-Ping
, p. 283 - 290 (2021/10/27)
The base-assisted Pd(cod)Cl2/Xantphos-catalyzed methoxycarbonylation of 1,3-butadiene (BD) to methyl-3-pentenoate (MP) was explored. Mechanistic studies suggest the excessive Xantphos (beyond an equimolar amount per Pd) as well as its substitute, pyridines of proper steric and electronic functionality, do participate the catalytic cycle and significantly reduce the activation energy by accelerating the rate-limiting methanolysis step. As thus, all the reaction parameters, especially the solvents, were optimized based on the Pd(cod)Cl2/Xantphos/4-hexylpyridine catalytic system, enabling the construction of a continuous process. Systematic optimization demonstrates that a yield of 82% of MP with a purity of 99.8% could be reached under steady-state operation.
Method for enhancing long-chain olefin hydrogen esterification reaction by ionic liquid
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Paragraph 0039-0064, (2021/06/13)
The invention relates to a method for preparing carboxylic ester through long-chain olefin hydrogen esterification reaction. The method is characterized by comprising the following steps: mixing long-chain olefin of which the C number is greater than or equal to 4 with a catalyst, a carbonyl source and alkyl alcohol according to a certain ratio, and carrying out hydrogen esterification reaction in a high-boiling-point solvent such as ester, ketone, ether, amide, aromatic hydrocarbon, sulfone (sulfoxide) or conventional ionic liquid. The first ligand is a bidentate phosphine ligand, and the second ligand is an ionic liquid containing a single-coordination central atom (N, P). The method has the advantages that raw material gas and liquid phases can be in full contact, the catalyst and a high-boiling-point solvent system can be recycled, and rapid separation of the catalyst and a product is achieved. In the conjugated olefin hydrogen esterification reaction, the olefin conversion rate is more than 80%, and the product selectivity is more than 85%; in the monoolefine hydrogen esterification reaction, the olefin conversion rate is greater than 90%, and the product selectivity is greater than 95%.
Selecting double bond positions with a single cation-responsive iridium olefin isomerization catalyst
Camp, Andrew M.,Kita, Matthew R.,Blackburn, P. Thomas,Dodge, Henry M.,Chen, Chun-Hsing,Miller, Alexander J.M.
supporting information, p. 2792 - 2800 (2021/03/01)
The catalytic transposition of double bonds holds promise as an ideal route to alkenes of value as fragrances, commodity chemicals, and pharmaceuticals; yet, selective access to specific isomers is a challenge, normally requiring independent development of different catalysts for different products. In this work, a single cation-responsive iridium catalyst selectively produces either of two different internal alkene isomers. In the absence of salts, a single positional isomerization of 1-butene derivatives furnishes 2-alkenes with exceptional regioselectivity and stereoselectivity. The same catalyst, in the presence of Na+, mediates two positional isomerizations to produce 3-alkenes. The synthesis of new iridium pincer-crown ether catalysts based on an aza-18-crown-6 ether proved instrumental in achieving cation-controlled selectivity. Experimental and computational studies guided the development of a mechanistic model that explains the observed selectivity for various functionalized 1-butenes, providing insight into strategies for catalyst development based on noncovalent modifications.
