Hydrogenation of Unsaturated Impurities in Ethylene Glycol Monoethers
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Solution Overview
Problem
Current methods for producing ethylene glycol monoethers, such as 2-butoxyethanol, often result in products with high concentrations of reactive unsaturated impurities like aldehydes, enals, and enols, which are difficult to separate and can interfere with the performance of the final product, especially in applications requiring high purity.
Innovation Solution
A method involving hydrogenation of impure alcohol feeds containing unsaturated contaminants in a hydrogenation reactor, using a catalyst, to convert at least 50 mole % of these contaminants into saturated products, followed by separation to produce a high-purity ethylene glycol monoether with reduced concentrations of hydrogenable impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional distillation methods are used to separate impurities from ethylene glycol monoether, then separation is achieved, but the product contains high concentrations of unsaturated impurities (aldehydes, enals, enols) that are difficult to remove
Solution Approach 1:
The patent applies hydrogenation to convert harmful unsaturated impurities (aldehydes, enals, enols) into saturated compounds. The unsaturated bonds in the impurities react with hydrogen to form saturated analogs that have different boiling points and can be separated from the product through distillation, thereby eliminating the harmful unsaturated species from the final product.
Solution Approach 2:
The patent changes the chemical state of the impurities from unsaturated to saturated through hydrogenation. This parameter change (saturation level) fundamentally alters the physical properties (boiling point, vapor pressure) of the impurities, enabling their separation from the ethylene glycol monoether product through conventional distillation methods.
2Manufacturing precision
If multiple distillation columns are used to remove impurities, then some separation is achieved, but thermodynamic and mass transfer limitations prevent complete removal of unsaturated impurities
Solution Approach 1:
The patent performs preliminary hydrogenation of the unsaturated impurities before the distillation process. By converting the unsaturated impurities to saturated compounds in advance, the subsequent distillation process becomes much more effective, as the saturated impurities have sufficiently different boiling points from the product to be removed efficiently through standard distillation columns.
3Productivity
If high temperatures are used in distillation columns to improve separation, then separation efficiency increases, but thermal decomposition and oxidative decomposition generate additional impurities
Solution Approach 1:
The patent performs the hydrogenation reaction under controlled conditions (moderate temperatures, presence of catalyst) to convert unsaturated impurities to saturated compounds before distillation. This preliminary action eliminates the need for extremely high temperatures during separation, as the saturated impurities can be removed at lower temperatures through distillation, thereby avoiding thermal decomposition and oxidative degradation of the product.
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 effectively reduces the concentration of unsaturated impurities in ethylene glycol monoethers to non-detectable levels, achieving a higher purity product suitable for applications that demand minimal residues and improved performance.
Implementation Method 1
contacting an impure alcohol feed comprising an alcohol compound and from about 50 ppm to about 5 weight %, based on the weight of the impure alcohol composition, of at least one hydrogenable contaminant having an unsaturated bond, with hydrogen in a hydrogenation reactor and in the presence of a hydrogenation catalyst to produce a reaction mixture comprising the alcohol compound and a hydrogenated contaminant product
Data Source
AI summary
There is provided is a method for making a higher purity alcohol comprising: a) contacting an impure alcohol composition comprising: (i) an alcohol compound; and (ii) from about 50 ppm to about 5 weight percent, based on the weight of the impure alcohol composition, of at least one hydrogenable contaminant having an unsaturated bond, with hydrogen in a hydrogenation reactor and in the presence of a hydrogenation catalyst to produce a reaction mixture comprising the alcohol compound and a hydrogenated contaminant product wherein at least 10 mole % of the at least one hydrogenable contaminant in the reaction mixture is converted; and b) separating the alcohol compound from at least a portion of the reaction mixture to produce an enriched alcohol composition having a lower concentration of the hydrogenated contaminant product. There is also provided an alcohol composition having less than about 500 ppm of at least one hydrogenable contaminant.