Dimethyl Carbonate Production via 3-Chloropropane-1,2-diol Recycling

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Solution Overview

Problem

Traditional methods for producing dimethyl carbonate result in the formation of ethylene glycol and propylene glycol as by-products, which are not reusable, whereas the proposed method recycles 3-chloropropane-1,2-diol as a raw material, avoiding these by-products and enhancing process efficiency.

Innovation Solution

The process involves reacting 3-chloropropane-1,2-diol with hydrochloric acid to form 1,3-dichloro-2-propanol, followed by reaction with sodium hydroxide to produce epichlorohydrin, then with carbon dioxide in the presence of tetrapropylammonium bromide to form (chloromethyl)ethylene carbonate, and finally with methanol using tetrabutyl titanate to produce dimethyl carbonate, with the 3-chloropropane-1,2-diol being recycled back into the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If traditional methods are used to produce dimethyl carbonate by reacting oxirane compounds with carbon dioxide, then dimethyl carbonate is produced, but ethylene glycol and propylene glycol are formed as non-reusable by-products

Engineering Contradiction:

Improveby-product reusabilityVSAvoidprocess efficiency

Core Design Contradiction:

Loss of substanceVSProductivity

Solution Approach 1:

The invention applies the discarding and recovering principle by capturing 3-chloropropane-1,2-diol that would traditionally be discarded as waste and recovering it for reuse in the reaction process. The by-product is separated from dimethyl carbonate and then fed back into the reactor as a reactant, converting waste into a valuable resource and eliminating the need for fresh 3-chloropropane-1,2-diol input.

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The invention implements feedback by creating a closed-loop system where 3-chloropropane-1,2-diol produced in the reaction is continuously separated and fed back into the reactor. This feedback mechanism maintains optimal reactant concentrations, improves conversion efficiency, and eliminates by-product accumulation, thereby enhancing overall process productivity.

Inventive Principle:

Principle #23Feedback

2Ease of manufacture

If the traditional process is used, then dimethyl carbonate production is achieved, but the process generates harmful by-products that cannot be recycled

Engineering Contradiction:

Improveprocess simplicityVSAvoidby-product formation

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention converts the harmful by-product (3-chloropropane-1,2-diol) into a beneficial resource by using it as a reactant in the same process. The substance that was previously considered waste and harmful is now utilized to drive the reaction forward, improving atom economy and eliminating the need for separate waste treatment processes.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of substance

If 3-chloropropane-1,2-diol is recycled in the process, then by-product formation is eliminated, but process complexity increases due to additional separation and recycling steps

Engineering Contradiction:

Improvematerial recyclingVSAvoidprocess structure

Core Design Contradiction:

Loss of substanceVSDevice complexity

Solution Approach 1:

The invention merges the reaction and separation functions into an integrated continuous process. The reaction reactor produces both dimethyl carbonate and 3-chloropropane-1,2-diol in situ, which are then separated and the latter is immediately fed back into the reactor. This merging of functions reduces the need for separate waste treatment units and simplifies the overall process structure despite the recycling loop.

Inventive Principle:

Principle #5Merging (Combining)

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 achieves high conversion and selectivity of dimethyl carbonate while eliminating the production of ethylene glycol and propylene glycol by-products, allowing for continuous recycling of 3-chloropropane-1,2-diol and improving the overall process efficiency.

Implementation Method 1

reacting 3-chloropropane-1,2-diol with hydrochloric acid to form 1,3-dichloro-2-propanol

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

reacting with sodium hydroxide to produce epichlorohydrin

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 3

reacting with carbon dioxide in the presence of tetrapropylammonium bromide to form (chloromethyl)ethylene carbonate

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 4

reacting with methanol using tetrabutyl titanate to produce dimethyl carbonate

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS10131620B2Process for producing dimethyl carbonate

Publication Date: 2018.11.20 CHANG CHUN PLASTICS CO LTD

AI summary

The present disclosure relates to a recycling method for producing dimethyl carbonate and dimethyl carbonate derivatives. The process is unique in that it produces a by-product that can be re-used in the process as a raw material for repeating the process. For example, when the process is directed to synthesizing dimethyl carbonate, glycerol is used as a starting material. Glycerol is also a by-product produced during formation of dimethyl carbonate, and therefore it can be re-used as starting material to generate more dimethyl carbonate.