Gold Hydrochlorination Catalyst Using Organic Solvent to Prevent Hot Spots
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Solution Overview
Problem
Existing gold-based catalysts for the hydrochlorination of acetylene to produce vinyl chloride monomer (VCM) suffer from unstable activity profiles and are prone to initial overheating, which can lead to deactivation due to the formation of local hot spots.
Innovation Solution
The catalyst production method is modified by using an organic solvent, such as acetone, in the impregnation solution to form a complex with a sulfur-containing ligand, altering the wetting and dispersion of gold on the support, resulting in a more stable activity profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an aqueous impregnation solution containing gold complex with sulfur-containing ligand is used, then the catalyst forms stable complexes that stabilize Au(I) and Au(III) active species, but the catalyst exhibits unstable activity profiles and is prone to initial overheating
Solution Approach 1:
The patent changes the solvent parameter from aqueous to organic (acetone) in the impregnation solution. This parameter change alters the wetting characteristics and dispersion of gold complex on the support, resulting in reduced initial activity and decreased prone to overheating while maintaining stable activity profiles throughout operation
2Productivity
If the catalyst is prepared with high initial activity, then productivity is improved, but deactivation occurs due to formation of local hot spots
Solution Approach 1:
The patent modifies the impregnation solution parameters by using organic solvent instead of aqueous solvent, which changes the distribution and wetting of catalyst precursors on the support. This results in more uniform heat distribution and reduced local hot spots, preventing deactivation while maintaining stable productivity over time
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 modified catalysts exhibit reduced initial activity and are less prone to overheating, maintaining stable performance over time, thus preventing deactivation and hot spot formation.
Implementation Method 1
combining a source of gold and a ligand in a solvent, wherein the solvent comprises an organic solvent which comprises or consists of acetone
Implementation Method 2
this change is thought to alter wetting between the catalyst and the impregnation solution
Implementation Method 3
The hydrochlorination of acetylene to produce VCM as the precursor to polyvinyl chloride (PVC)
Implementation Method 4
drying the product of step (ii) to obtain the catalyst
Data Source
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AI summary
The specification describes a method for the production of a hydrochlorination catalyst, comprising the steps of: i) preparing an impregnation solution by combining a source of gold and a ligand in a solvent, wherein the solvent comprises an organic solvent; ii) impregnating a support with the impregnation solution from step (i); and iii) drying the product of step (ii) to obtain the catalyst. Also described are hydrochlorination catalysts comprising a complex of gold and a ligand of Formula (I) supported on a support. These catalysts are particularly suitable for the conversion of acetylene to vinyl chloride monomer.