Butadiene Telomerization Phosphine Ligand Selectivity
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Solution Overview
Problem
The existing telomerization processes for 1,3-butadiene produce undesirable by-products such as 2- and 3-octenes, which contaminate the desired product 1-octene, and struggle to maximize the molar ratio of linear 1-alkoxy-2,7-octadiene to branched 3-alkoxy-1,7-octadiene in the telomerization product mixture.
Innovation Solution
A process involving the telomerization of butadiene with an organic hydroxy compound in the presence of a palladium catalyst and a phosphine ligand, specifically using a phosphine ligand with certain aryl substituents, to achieve a high molar ratio of linear to branched products and maintain catalyst efficiency, thereby minimizing the production of unwanted by-products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional telomerization processes are used, then butadiene can be converted to octadiene products, but the molar ratio of linear to branched products is not maximized and undesirable by-products are formed
Solution Approach 1:
The patent applies parameter changes by modifying the phosphine ligand structure to have specific aryl substituents (formula II with R being C1-C20 hydrocarbyloxyl substituent on ortho position) and optimizing the ligand-to-palladium ratio (≥1:1), along with controlling reaction conditions (temperature 40-100°C, pressure 1-20 atm) to achieve a linear-to-branched product molar ratio of at least 25:1 and catalyst efficiency of at least 150 g/g/hr
2Productivity
If catalyst efficiency is increased, then productivity improves, but selectivity towards linear product may decrease leading to more by-products
Solution Approach 1:
The patent employs a composite catalyst system combining palladium metal with specifically designed phosphine ligands featuring aryl substituents with hydrocarbyloxyl groups. This composite catalyst structure (Pd with ligand formula II) achieves both high productivity (≥150 g/g/hr) and high selectivity (linear-to-branched ratio ≥25:1) by creating a synergistic effect between the metal center and the tailored ligand environment
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
The process effectively increases the molar ratio of linear to branched products, enhancing the production of 1-octene by achieving a catalyst efficiency of at least 150 g of linear product per g of palladium per hour, while reducing the presence of undesirable by-products like 2- and 3-octenes.
Implementation Method 1
The telomerization reaction is generally catalyzed by a ligand complex of a transition metal selected from a group consisting of iron (Fe), cobalt (Co), nickel (Ni), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir) and platinum (Pt). Preferably, the transition metal is palladium. Phosphines are examples of ligands that can form efficient palladium catalysts suitable for use in producing 1-alkoxy-2,7-octadiene.
Data Source
AI summary
In an improved process for telomerizing butadiene, contact butadiene and an organic hydroxy compound represented by formula ROH (I), wherein R is a substituted or unsubstituted C1-C20-hydrocarbyl and the organic hydroxy compound is not glycerol, in a reaction fluid in the presence of a palladium catalyst and a phosphine ligand represented by formula PAr3 (II), wherein each Ar is independently a substituted or unsubstituted aryl having a hydrogen atom on at least one ortho position, at least two Ar groups are ortho-hydrocarbyloxyl substituted aryls. The phosphine ligand has a total of two (2), three (3), four (4), five (5), or six (6) substituted or unsubstituted C1-C20-hydrocarbyloxyls, and optionally, any two adjacent substituents on an Ar group can be bonded to form a 5- to 7-membered ring.