Stereoselective Chlorohydrocarbon Production via Base-Mediated Alcohol Chlorination
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Solution Overview
Problem
Existing methods for producing chlorohydrocarbons with conjugated double bonds are costly due to the use of expensive metal salts and have high environmental impact from toxic solvents, and they often result in low yields and isomerization of double bonds.
Innovation Solution
A method involving the chlorination of alcohols with a chlorinating agent in the presence of a base, without the use of metal salts, to produce chlorohydrocarbons with conjugated double bonds, using a solvent system that reduces isomerization and lowers production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thionyl chloride is used for chlorination, then the chlorination reaction proceeds efficiently, but isomerization of conjugated double bonds is accelerated reducing product purity
Solution Approach 1:
The patent introduces an organic base (triethylamine, pyridine, or N,N-dimethylaminopyridine) as an intermediary substance to mediate the chlorination reaction. This base acts as a catalyst and reaction mediator that enables efficient chlorination while preventing isomerization of the conjugated double bonds, thus resolving the contradiction between reaction efficiency and product purity.
2Ease of manufacture
If expensive metal salts such as lithium chloride are used in equivalent amount or more, then chlorination can be achieved, but production cost increases making it unsuitable for industrial production
Solution Approach 1:
The patent replaces expensive metal salts with inexpensive organic bases that can be used in catalytic amounts. These organic bases are readily available, low-cost reagents that perform the chlorination function effectively without requiring equivalent or excess amounts, thereby dramatically reducing production costs for industrial-scale manufacturing.
3Ease of operation
If methylene chloride is used as solvent for chlorination with triethylamine, then the reaction proceeds, but the method is limited to highly reactive substrates and gives lower yields, and the solvent has high environmental load and toxicity
Solution Approach 1:
The patent changes the reaction parameters by using different solvents (acetonitrile, N,N-dimethylformamide, toluene, or dichloroethane) and adjusting the base catalyst type and amount. These parameter changes expand the method's applicability to various substrate reactivities while improving yields and reducing environmental impact, overcoming the limitations of the methylene chloride system.
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 method allows for the stereoselective production of chlorohydrocarbons with minimal isomerization of conjugated double bonds, enabling mass production at a lower cost and with reduced environmental impact.
Implementation Method 1
chlorinating an alcohol having conjugated double bonds with a chlorinating agent in a solvent in the presence of a base
Data Source
AI summary
Provided is a method for producing a chlorohydrocarbon having conjugated double bonds by stereoselectively chlorinating an alcohol having conjugated double bonds. More specifically, provided is a method for producing a chlorohydrocarbon having conjugated double bonds, the method including a step of chlorinating an alcohol having conjugated double bonds with a chlorinating agent in a solvent in the presence of a base and in the absence of metal salt for chlorination of the alcohol, and the alcohol being represented by the formula (1):RCH═CHCH═CH—Z—OH (1)wherein R represents a hydrogen atom or a linear, branched or cyclic C1-17 monovalent hydrocarbon group which may have at least one double bond or at least one triple bond; and Z represents a linear, branched or cyclic C1-17 divalent hydrocarbon group which may have at least one double bond or at least one triple bond.