Dimethyl Disulphide Production via In-Situ Hydrogen Sulphide Recycling
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Solution Overview
Problem
Current methods for producing dimethyl disulphide (DMDS) from hydrocarbon, hydrogen sulphide, and sulphur face drawbacks such as the need for additional steps, secondary product formation, and eco-toxicity, making them inefficient and environmentally unfriendly.
Innovation Solution
A process involving the reaction of a hydrocarbon charge with hydrogen sulphide to form carbon disulphide and hydrogen, followed by hydrogenation to produce methyl mercaptan, which is then reacted with sulphur to form DMDS, allowing for recycling of hydrogen sulphide and eliminating the need for excess hydrogen sulphide addition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If methanol is used as starting material for methyl mercaptan synthesis, then the reaction pathway is established, but additional purification steps are required due to secondary product formation
Solution Approach 1:
The invention extracts and removes the problematic methanol synthesis step from the overall process. By using carbon monoxide directly instead of methanol, the source of secondary products (dimethyl ether, dimethyl sulfide, water) is eliminated, thereby removing the need for complex purification steps while maintaining the ability to produce methyl mercaptan
Solution Approach 2:
Instead of following the conventional path of methanol → methyl mercaptan, the invention inverts the approach by using carbon monoxide → methyl mercaptan. This reversal eliminates the methanol intermediate that causes secondary product formation and subsequent purification requirements
2Ease of manufacture
If carbon monoxide is used to produce methyl mercaptan, then methanol synthesis step is eliminated, but synthesis gas preparation and CO/H2 ratio adjustment are required
Solution Approach 1:
The invention makes the process self-sufficient by producing both carbon monoxide and hydrogen in-situ through steam reforming of a hydrocarbon feedstock. The reforming step generates synthesis gas that is then directly used for methyl mercaptan synthesis, eliminating the need for external synthesis gas preparation and CO/H2 ratio adjustment facilities
3Quantity of substance
If steam reforming is performed to obtain synthesis gas, then carbon monoxide and hydrogen are produced, but additional equipment and process control are needed
Solution Approach 1:
The invention merges multiple process functions into a single integrated system. The steam reforming unit simultaneously produces both carbon monoxide and hydrogen in the required stoichiometric ratio, combining what would otherwise require separate preparation and mixing steps into one unified operation, thereby reducing overall equipment complexity
4Productivity
If conventional DMDS production from methyl mercaptan and sulphur is used, then high yield is achieved, but hydrogen sulphide management and eco-toxicity issues arise
Solution Approach 1:
The invention converts the harmful hydrogen sulfide byproduct into a beneficial reactant. The hydrogen sulfide that would normally be discarded or require costly treatment is instead recycled and fed back into the steam reforming step, where it participates in the reaction to produce more synthesis gas, thereby eliminating emissions and reducing eco-toxicity while maintaining high DMDS yield
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 process enhances yield and selectivity, reduces eco-toxicity, and operates more economically by consuming and recycling hydrogen sulphide, thereby avoiding additional synthesis steps and secondary product formation.
Implementation Method 1
reaction of at least one hydrocarbon charge in the presence of hydrogen sulphide (H2S) and optionally of sulphur (S) to form carbon disulphide (CS2) and hydrogen (H2)
Implementation Method 2
hydrogenation reaction of said carbon disulphide (CS2) in the presence of said hydrogen (H2), both obtained in step a), to form methyl mercaptan (CH3SH), hydrogen sulphide (H2S)
Data Source
AI summary
The present invention relates to a method for preparing dimethyl disulphide, in batches or continuously, preferably continuously, said method including at least the following steps: a) reacting at least one hydrocarbon feedstock in the presence of hydrogen sulphide (H2S) and optionally sulphur (S) such as to form carbon disulphide (CS2) and hydrogen (H2); b) reacting said carbon disulphide (CS2) by hydrogenation in the presence of said hydrogen (H2) obtained in step a), such as to form methyl mercaptan (CH3SH), hydrogen sulphide (H2S) and optionally hydrogen (H2); c) optionally, but preferably, recirculating said hydrogen sulphide (H2S) formed in step b) to step a); d) reacting the methyl mercaptan formed in step b) with sulphur such as to form dimethyl disulphide and hydrogen sulphide; e) optionally recirculating the hydrogen sulphide formed during step d) to step a); and f) recovering the dimethyl disulphide.