Catalyst Acidity Control for Dipropylene Glycol Selectivity
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Solution Overview
Problem
Current methods for producing dipropylene glycol and tripropylene glycol do not effectively control the proportion of 1,1′-oxybis-2-propanol and 1,1′-[(1-methyl-1,2-ethanediyl)bis(oxy)]bis-2-propanol, respectively, which are crucial for their industrial applications.
Innovation Solution
A method involving a reaction between propylene oxide and water in the presence of a catalyst comprising vanadium, niobium, or tantalum, with a Hammett acidity function (H) of 9.3 or less, to selectively produce dipropylene glycol and tripropylene glycol with desired proportions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If propylene oxide reacts with excessive water in the absence of a catalyst, then dipropylene glycol and tripropylene glycol are produced as byproducts, but the selectivity and proportion of specific isomers (1,1′-oxybis-2-propanol and 1,1′-[(1-methyl-1,2-ethanediyl)bis(oxy)]bis-2-propanol) cannot be effectively controlled
Solution Approach 1:
The patent applies parameter changes by carefully controlling the water to propylene oxide molar ratio within 0.5 to 2.0, using a catalyst with specific acidity (Hammett acidity function H0 between -1.0 and 9.3), and maintaining reaction temperature between 100°C and 200°C. These parameter optimizations enable precise control over the proportion of desired isomers in the glycol mixture while managing process complexity.
Solution Approach 2:
The patent introduces a catalyst as an intermediary substance with specific acidity characteristics (Hammett acidity function H0 between -1.0 and 9.3) to mediate the reaction between propylene oxide and water. This catalyst enables selective production of dipropylene glycol and tripropylene glycol with controlled isomer proportions, resolving the contradiction between manufacturing precision and process simplicity.
2Productivity
If a catalyst with high acidity is used to increase reaction rate, then productivity improves, but selectivity to desired glycol isomers decreases
Solution Approach 1:
The patent optimizes the catalyst acidity parameter by specifying a Hammett acidity function H0 range of -1.0 to 9.3, which balances reaction rate and selectivity. This parameter control ensures that the reaction proceeds at adequate speed while maintaining high selectivity for the desired glycol isomers, resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The patent employs dynamic optimization by adjusting multiple reaction parameters simultaneously - water to propylene oxide ratio (0.5 to 2.0), temperature (100°C to 200°C), and catalyst acidity (H0: -1.0 to 9.3) - to achieve the optimal balance between reaction rate and selectivity, rather than fixing any single parameter.
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 allows for the highly selective production of dipropylene glycol and tripropylene glycol with 1,1′-oxybis-2-propanol and 1,1′-[(1-methyl-1,2-ethanediyl)bis(oxy)]bis-2-propanol in the desired range of 0.10 to 0.70, enhancing their selectivity and industrial applicability.
Implementation Method 1
making a reactant comprising propylene oxide and water react in the presence of a catalyst, wherein the catalyst comprises at least one element selected from the group consisting of vanadium, niobium, and tantalum, and the Hammett acidity function (H) of the catalyst satisfies H≦9.3
Data Source
AI summary
The objective of the present invention is to provide a method for the highly selective production of dipropylene glycol containing 1,1′-oxybis-2-propanol in a proportion of 0.10 to 0.70 and/or tripropylene glycol containing 1,1′-[(1-methyl-1,2-ethanediyl)bis(oxy)]bis-2-propanol in a proportion of 0.10 to 0.70. The present invention is a method for producing dipropylene glycol containing 1,1′-oxybis-2-propanol in a proportion of 0.10 to 0.70 and/or tripropylene glycol containing 1,1′-[(1-methyl-1,2-ethanediyl)bis(oxy)]bis-2-propanol in a proportion of 0.10 to 0.70, the method comprising a reaction step of making a reactant comprising propylene oxide and water react in the presence of a catalyst, wherein the catalyst comprises at least one element selected from the group consisting of vanadium, niobium, and tantalum, and the Hammett acidity function (H) of the catalyst satisfies H≦9.3.