1,4-Butanediol Purification via Segmented Distillation
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Solution Overview
Problem
Current purification processes for 1,4-butanediol do not achieve high enough purity for applications requiring high molecular weights in polyester or polyurethane production, as they leave behind impurities like gamma-butyrolactone and other secondary components.
Innovation Solution
A continuous distillation process involving multiple columns, where the molar ratio of oxygen to 1,4-butanediol is carefully controlled to minimize impurity formation, and the product stream is separated into distinct fractions to recycle and incinerate low-purity components, achieving high-purity 1,4-butanediol by removing low boilers and high boilers in sequential distillation stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional distillation processes are used to purify crude 1,4-butanediol, then the purification process can be completed, but the purity level is insufficient for high-performance polyester or polyurethane production
Solution Approach 1:
The distillation process is divided into five separate columns (I-V), each performing a specific separation function. Column I removes low boilers, Column II removes water, Column III separates high boilers, Column IV recovers pure 1,4-butanediol, and Column V handles residual high boilers. This segmentation allows each column to be optimized for its specific task, achieving high purity (>99.5%) while maintaining manageable complexity through functional specialization.
Solution Approach 2:
A side stream from Column IV serves as an intermediary to remove specific impurities (gamma-butyrolactone and acetal) that conventional processes miss. This intermediate separation step targets problematic components without disrupting the main purification flow, enabling high purity output for demanding applications.
2Manufacturing precision
If multiple distillation columns are used to achieve high purity, then the purity level improves, but the process complexity and equipment requirements increase
Solution Approach 1:
The purification task is segmented across five columns, each with a defined function. This distribution allows parallel operation and reduces the burden on any single column, achieving high purity through coordinated action rather than over-engineering individual units.
Solution Approach 2:
The process systematically discards impurities at appropriate stages (low boilers in Column I, water in Column II, high boilers in Columns III-V) while recovering pure 1,4-butanediol in Column IV. This organized disposal and recovery strategy maximizes purity while minimizing waste and equipment over-complexity.
3Productivity
If oxygen is present in the distillation column, then the distillation process can proceed, but impurity formation increases
Solution Approach 1:
The distillation columns operate under nitrogen atmosphere or vacuum conditions, creating an inert environment that prevents oxygen from reacting with 1,4-butanediol and forming impurities. This allows continuous distillation operation while eliminating the harmful effect of oxygen-induced impurity formation, maintaining both productivity and purity.
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 process achieves a purity of >99.5% 1,4-butanediol, significantly reducing impurities like 2-methyl-1,4-butanediol and acetal, making it suitable for high-performance polyester and polyurethane production.
Implementation Method 1
purification of crude, water-containing 1,4-butanediol (1) by distillation, in which 1,4-butanediol is freed from components boiling lower (lower) than 1,4-butanediol (low boilers) and water
Implementation Method 2
after removal of water and low boilers is passed through three further distillation columns
Data Source
Figure 1
AI summary
The object of the present invention is a method for the purifying distillation of raw, aqueous 1,4-butanediol (1), in which 1,4-butanediol (5) freed of components boiling at a lower point than 1,4-butanediol and water is conducted through three distillation columns (III, IV, V), components boiling at a higher point than 1,4-butanediol are drawn from the bottom of the first column and conducted to the third (7), 1,4-butanediol is conducted from the top of the first column (6) into the second, the bottom product of the second column (9) is conducted into the third, the top product of the third column (11) is returned at least partially to the first column, characterized in that the pure 1,4-butanediol is removed from the side outlet of the second column.