Hydroisomerization of Durene and Pseudocumene in Synthetic Gasoline
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Solution Overview
Problem
Synthetic gasoline produced from methanol or methanol/dimethylether conversion contains durene and pseudocumene, which have high freezing points and limited octane boosting potential, leading to engine filter plugging issues and suboptimal octane ratings.
Innovation Solution
A process involving hydroisomerization and dealkylation/disproportionation of durene and pseudocumene using a sulfided metal catalyst supported on an acidic carrier, specifically nickel on ZSM-5 zeolite with alumina, to convert durene into isodurene and prehnitene, and pseudocumene into mesitylene, improving cold flow properties and octane numbers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If durene and pseudocumene are present in synthetic gasoline, then good octane numbers are achieved, but freezing points become too high causing engine filter plugging
Solution Approach 1:
The patent changes the molecular structure parameters of durene and pseudocumene through hydroisomerization and dealkylation/disproportionation reactions. Durene is converted to isodurene and prehnitene with lower melting points, while pseudocumene is converted to mesitylene and hemimellitene. This structural parameter change resolves the contradiction by maintaining octane quality while lowering freezing points to prevent filter plugging.
Solution Approach 2:
The patent extracts the problematic durene and pseudocumene components from the gasoline mixture through selective catalytic reactions. By removing these high-freezing-point compounds and replacing them with isomerized products having lower freezing points, the reliability issue of filter plugging is eliminated while preserving the desired octane characteristics.
2Productivity
If conventional catalysts are used for hydroisomerization, then durene conversion occurs, but excessive hydrogen consumption and yield loss occur due to hydrogenolysis
Solution Approach 1:
The patent modifies the catalyst's chemical state by sulfiding the metal component (nickel, cobalt, or iron), which fundamentally changes its selectivity parameters. The sulfided catalyst maintains high durene conversion efficiency through hydroisomerization while suppressing the hydrogenolysis pathway that causes excessive hydrogen consumption and yield loss. This parameter change in catalyst composition resolves the contradiction between productivity and substance loss.
3Reliability
If pseudocumene is converted to mesitylene, then octane number is improved, but additional process complexity is required
Solution Approach 1:
The patent merges multiple functions into a single catalytic system: the sulfided metal catalyst simultaneously performs hydroisomerization of both durene (to isodurene and prehnitene) and pseudocumene (to mesitylene and hemimellitene). This combined approach improves octane number through pseudocumene conversion while avoiding additional process complexity, as both conversions occur in one reactor with one catalyst.
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 process effectively reduces durene content, lowers freezing points, and enhances octane ratings by converting durene to isodurene and pseudocumene to mesitylene, improving gasoline's cold flow properties and octane performance without substantial hydrogen consumption or yield loss.
Implementation Method 1
a sulfided metal catalyst supported on a on an acidic carrier to provide gasoline with improved characteristics
Implementation Method 2
converting durene (1,2,4,5-tetramethylbenzene) to isodurene (1,2,3,5-tetramethylbenzene) and prehnitene (1,2,3,4-tetramethylbenzene) and converting pseudocumene (1,2,4-trimethylbenzene) to mesitylene (1,3,5-trimethylbenzene) and hemimellitene ((1,2,3-trimethylbenzene)
Implementation Method 3
an acid function, which is provided by supporting the sulfided base metal on an acidic carrier, thereby converting durene
Data Source
AI summary
Process and catalyst for upgrading gasoline comprising durene (1,2,4,5-tetramethylbenzene) and pseudodocumene, the process comprises hydroisomerization of durene (1,2,4,5-tetramethylbenzene) and pseudocumene (1,2,4-trimethylbenzene) contained in the gasoline in presence of a catalyst comprising a sulfided base metal supported on an acidic carrier, thereby converting durene (1,2,4,5-tetramethylbenzene) to isodurene (1,2,4,5-tetramethylbenzene) and prehnitene (1,2,3,4-tetramethylbenzene) and converting pseudocumene (1,2,4-trimethylbenzene) to mesitylene (1,3,5-trimethylbenzene).