Ether Solvent Isothiazole Synthesis Safety
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Solution Overview
Problem
Current processes for producing 3,4-dichloro-5-cyanoisothiazole are unsafe due to the use of aprotic polar solvents like N,N-dimethylformamide and chlorine, which can lead to reaction runaway or explosions, and require special raw materials and high temperatures, making them unsuitable for industrial-scale production.
Innovation Solution
A process involving the introduction of chlorine into succinonitrile and sulfur at 70°C or more in the presence of an ether compound, eliminating the need for aprotic polar solvents and allowing for a safer, one-step production of 3,4-dichloro-5-cyanoisothiazole without the risks associated with toxic or flammable materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a process using N,N-dimethylformamide and chlorine is employed to produce 3,4-dichloro-5-cyanoisothiazole, then the isothiazole compound can be synthesized, but there is a possibility of reaction runaway or explosion due to the simultaneous use of these materials
Solution Approach 1:
The patent removes N,N-dimethylformamide from the reaction system and replaces it with ether compounds (such as dibutyl ether, diisopropyl ether, or diphenyl ether). This extraction of the hazardous solvent eliminates the risk of reaction runaway while maintaining the feasibility of the chlorination process to produce 3,4-dichloro-5-cyanoisothiazole
Solution Approach 2:
The patent introduces ether compounds as intermediary solvents that mediate between the reactants (succinonitrile, sulfur, and chlorine) without causing the hazardous side reactions associated with N,N-dimethylformamide. These ether intermediaries provide a safe reaction environment while enabling the synthesis to proceed
2Reliability
If a process using trichloroacetonitrile and sulfur is employed to produce 3,4-dichloro-5-cyanoisothiazole, then the compound can be synthesized, but high temperature of 200 to 300°C is required
Solution Approach 1:
The patent changes the temperature parameter from 200-300°C to 0-50°C by using ether compounds as solvents. This parameter change allows the reaction to proceed at lower temperatures while maintaining safety and producing the desired isothiazole compound
3Reliability
If a process using dichlorofumaronitrile and sulfur is employed to produce 3,4-dichloro-5-cyanoisothiazole, then the compound can be synthesized, but high temperature of 230 to 300°C is required
Solution Approach 1:
The patent changes the temperature parameter from 230-300°C to 0-50°C by employing ether compounds as solvents. This parameter modification enables the synthesis to occur at lower temperatures while ensuring production safety
4Reliability
If fumaronitrile or maleonitrile with sulfur chloride in an aprotic polar solvent is employed to produce the isothiazole compound, then the synthesis can proceed, but two steps from succinonitrile are required and the solvent requires water working-up
Solution Approach 1:
The patent removes aprotic polar solvents (such as N,N-dimethylformamide) from the process and replaces them with ether compounds. This extraction eliminates the need for water working-up and simplifies the process by allowing direct isolation of the product without additional purification steps
Solution Approach 2:
The patent consolidates the synthesis into a single step from succinonitrile by using ether compounds as solvents, eliminating the need for intermediate isolation and re-dissolution steps that are required in multi-step processes
5Reliability
If carbon disulfide and sodium cyanide are used as raw materials to produce 3,4-dichloro-5-cyanoisothiazole, then the compound can be synthesized, but toxic and flammable materials are involved
Solution Approach 1:
The patent replaces hazardous raw materials (carbon disulfide and sodium cyanide) with safer alternatives (ether compounds as solvents and succinonitrile as starting material). This conversion transforms a harmful process into a safe one while maintaining the ability to produce the desired isothiazole compound
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 provides a safer, more economical, and environmentally friendly method for producing 3,4-dichloro-5-cyanoisothiazole, reducing waste and operational hazards, and enabling industrial-scale production without the need for high temperatures or expensive catalysts.
Implementation Method 1
introducing chlorine into succinonitrile and sulfur at 70°C or more in the presence of an ether compound, to carry out a reaction between the succinonitrile, the sulfur and the chlorine
Data Source
AI summary
[Problem to be Solved] To provide an industrially preferred process for producing an isothiazole compound which avoids the simultaneous use of N,N-dimethylformamide or the like and chlorine. [Solution] A process for producing an isothiazole compound represented by a general formula (3) (wherein R is a cyano group or the like; and X is a chlorine atom or the like) which comprises introducing a halogen represented by a general formula (2) X2 (2) (wherein X is as defined above) into a nitrile compound represented by a general formula (1) (wherein R is as defined above) and sulfur at 70°C or more in the presence of an ether compound represented by a general formula (7) R1-O-R2 (7) (wherein R1 and R2 are the same or different and each represent an alkyl group or the like) to carry out a reaction between the nitrile compound, the sulfur and the halogen.