Palladium-Phosphine Catalyst for Diene Alkoxycarbonylation
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Solution Overview
Problem
The existing process for producing di- or tricarboxylic acid esters through alkoxycarbonylation of dienes with conjugated double bonds requires multiple steps and different catalysts, resulting in waste and high costs due to the need for separate catalysts in each step.
Innovation Solution
A process involving the use of a phosphine ligand and a palladium catalyst precursor, such as PdCl2, PdBr2, or Pd(acac)2, with a diene, alcohol, and CO, under heating, to directly convert dienes into di- or tricarboxylic acid esters in a single step, minimizing by-products like β,γ-unsaturated monocarboxylic acid esters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-step alkoxycarbonylation process is used to convert 1,3-butadiene to dimethyl adipic ester, then the reaction can proceed with established catalyst systems, but it requires multiple steps and different catalysts which produce waste and result in high manufacturing costs
Solution Approach 1:
The patent combines two separate alkoxycarbonylation steps into a single reaction step by using a palladium catalyst system with a specific phosphine ligand that can catalyze both the formation of the intermediate unsaturated ester and its subsequent conversion to the diester product simultaneously, thereby simplifying the process and eliminating the need for catalyst exchange
Solution Approach 2:
The palladium catalyst system with phosphine ligand exhibits multi-functionality by performing multiple catalytic roles in sequence within a single reaction system - first catalyzing the alkoxycarbonylation to form the unsaturated ester intermediate, then catalyzing the second alkoxycarbonylation to form the final diester product, making the catalyst system universal for both transformation steps
2Manufacturing precision
If a two-step process with different catalysts is used, then each step can be optimized for its specific transformation, but it results in unnecessary waste and high manufacturing costs
Solution Approach 1:
By merging the two reaction steps into one continuous process using a single catalyst system, the patent eliminates the waste associated with catalyst disposal and replacement between steps, while the phosphine ligand ensures high selectivity for the desired diester product throughout the combined reaction sequence
Solution Approach 2:
The patent implements continuous useful action by maintaining an active palladium catalyst system throughout the entire transformation from 1,3-butadiene to dimethyl adipic ester without interruption or catalyst replacement, ensuring that the catalytic activity continues uninterrupted through both transformation stages, thereby eliminating waste from catalyst disposal
3Productivity
If traditional alkoxycarbonylation methods are used, then the reaction can proceed under established conditions, but it produces significant amounts of β,γ-unsaturated monocarboxylic acid ester as byproduct
Solution Approach 1:
The patent changes key reaction parameters by introducing a specific phosphine ligand (such as triphenylphosphine or its derivatives) to the palladium catalyst system, which modifies the catalyst's electronic and steric properties to favor the formation of the desired diester product over the β,γ-unsaturated monocarboxylic acid ester byproduct, thereby improving product purity while maintaining productivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the efficient production of di- or tricarboxylic acid esters in a single reaction step with high yields and reduced waste, compared to traditional two-step processes, by utilizing a combination of phosphine ligands and palladium catalysts to directly convert dienes into the desired esters.
Implementation Method 1
The alkoxycarbonylation is catalysed by a Pd complex which is formed in situ from a compound containing Pd and a free phosphine ligand
Implementation Method 2
e) Heating the reaction mixture, whereby the diene is converted to a di- or tricarboxylic acid ester
Data Source
AI summary
The invention relates to a process comprising the process steps of: a) providing a diene with two conjugated double bonds; b) adding a phosphine ligand and a catalyst precursor selected from palladium dichloride, palladium dibromide, palladium diiodide, palladium(II) acetylacetonate, palladium(II) acetate, bis-(dibenzylidene acetone)palladium, bis(acetonitrile)dichloropalladium(II), and palladium(cinnamyl) dichloride; c) adding an alcohol; d) supplying CO; and e) heating the reaction mixture, wherein the diene is converted to a di- or tricarboxylic acid ester. wherein the phosphine ligand is a compound according to formula (I) wherein R1, R2, R3, R4 are selected from -(C1-C12)-alkyl, -(C6-C20)-aryl, -(C3-C12)-cycloalkyl, -(C3-C12)-heterocycloalkyl, -(C3-C20)-heteroaryl; R5, R6 are selected from -H, -(C1-C12)-alkyl, -(C6-C20)-aryl, -(C3-C12)-cycloalkyl, -(C3-C12)-heterocycloalkyl, -(C3-C20)-heteroaryl;und R1, R2, R3, R4, R5, R6, falls diese für -(C1-C12)-Alkyl, -(C6-C20)-Aryl, -(C3-C12)-Cycloalkyl,-(C3-C12)-Heterocycloalkyl oder -(C3-C20)-Heteroaryl stehen, jeweils unabhängig voneinander mit einem oder mehreren Substituenten ausgewählt aus -(C1-C12)-Alkyl, -(C3-C12)-Cycloalkyl, -(C3-C12)-Heterocycloalkyl, -O-(C1-C12)-Alkyl, -O-(C1-C12)-Alkyl-(C6-C20)-Aryl, -O-(C3-C12)-Cycloalkyl, -S-(C1-C12)-Alkyl, -S-(C3-C12)-Cycloalkyl, -COO-(C1-C12)-Alkyl, -COO-(C3-C12)-Cycloalkyl, -CONH-(C1-C12)-Alkyl, -CONH-(C3-C12)-Cycloalkyl,-CO-(C1-C12)-Alkyl, -CO-(C3-C12)-Cycloalkyl, -N-[(C1-C12)-Alkyl]2, -(C6-C20)-Aryl, -(C6-C20)-Aryl-(C1-C12)-Alkyl, -(C6-C20)-Aryl-O-(C1-C12)-Alkyl, -(C3-C20)-Heteroaryl, -(C3-C20)-Heteroaryl-(C1-C12)-Alkyl, -(C3-C20)-Heteroaryl-O-(C1-C12)-Alkyl, -COOH, -OH, -SO3H, -NH2, Halogen substituiert sein können.;