Alkenyl-Substituted Cyclic Anhydride Paper Sizing via Alkali Metal Isomerization
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Solution Overview
Problem
The existing processes for preparing alkenyl-substituted cyclic anhydrides, used as paper sizing agents, face challenges with the use of alpha-olefins containing high vinylidene isomers, which require high-temperature isomerization and subsequent distillation to remove catalyst residues, resulting in lower performance compared to those made from linear alpha-olefins.
Innovation Solution
A process involving the isomerization of olefinically unsaturated hydrocarbons with an alkali metal catalyst, followed by reaction with a cyclic anhydride of an unsaturated dicarboxylic acid, allowing the use of alpha-olefins with high vinylidene content without the need for distillation, and producing alkenyl-substituted cyclic anhydrides with improved paper sizing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If iron pentacarbonyl catalyst is used for isomerization of alpha-olefins, then isomerization can be performed, but the process requires high temperatures and subsequent distillation to remove catalyst residues, resulting in lower performance ASA compounds
Solution Approach 1:
The patent changes the catalyst from iron pentacarbonyl to alkali metal hydroxide, which operates at lower temperatures and does not require distillation for residue removal. This parameter change in catalyst type resolves the contradiction by maintaining isomerization effectiveness while eliminating the need for high-temperature processing and complex separation steps.
Solution Approach 2:
The alkali metal hydroxide catalyst can be used in smaller amounts and does not require expensive distillation equipment for residue removal. The catalyst residues remain in the reaction mixture and do not interfere with the subsequent reaction with maleic anhydride, eliminating the need for complex purification equipment and operations.
2Ease of manufacture
If alpha-olefins with high vinylidene content are used, then raw material cost is reduced and availability is improved, but the resulting ASA compounds have lower paper sizing performance
Solution Approach 1:
The patent changes the reaction conditions by using alkali metal hydroxide catalyst at lower temperatures, which enables the effective utilization of alpha-olefins with high vinylidene content. This parameter change allows the reaction to proceed efficiently with less desirable raw materials, resolving the contradiction between raw material availability and product performance.
3Manufacturing precision
If high-temperature isomerization is performed to convert vinylidene olefins, then internal olefins are produced, but catalyst residues and colouring require distillation removal before reaction with maleic anhydride
Solution Approach 1:
The alkali metal hydroxide catalyst residues and colouring do not require expensive distillation for removal. The impurities remain in the reaction mixture and do not interfere with the subsequent reaction with maleic anhydride, eliminating the need for complex purification steps and improving overall process efficiency.
Solution Approach 2:
The alkali metal hydroxide acts as an intermediary catalyst that enables the isomerization to proceed under milder conditions without generating problematic residues. The catalyst facilitates the conversion of vinylidene olefins to internal olefins while remaining compatible with the subsequent reaction conditions, avoiding the need for intermediate purification.
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 enables the production of alkenyl-substituted cyclic anhydrides with acceptable to good paper sizing performance using alpha-olefins with high vinylidene content, reducing the need for distillation and maintaining catalyst stability, thus improving the efficiency and effectiveness of the paper sizing agents.
Implementation Method 1
isomerizing the olefin double bond from a terminal to an internal position... by contacting them with a catalyst comprising an alkali metal on a carrier
Implementation Method 2
reacting the resulting isomerized olefinic C6-C28 hydrocarbons with a cyclic anhydride of an unsaturated dicarboxylic acid to form the alkenyl-substituted cyclic anhydride compound
Implementation Method 3
hydrophobic tails that are oriented away from the fibres. The nature and orientation of these hydrophobic tails causes the fibres to repel water
Data Source
AI summary
The present invention pertains to a process for the preparation of an alkenyl-substituted cyclic anhydride compound comprising the steps of subjecting one or more olefinically unsaturated C6 - C28 hydrocarbons of which at least 30% by weight is alpha-olefin to a double bond isomerization step by contacting them with a catalyst comprising an alkali metal on a carrier, and reacting the resulting isomehzed olefinic C6 - C28 hydrocarbons with a cyclic anhydride of an unsaturated dicarboxylic acid to form the alkenyl-substituted cyclic anhydride compound. Furthermore, it pertains to the thus obtained alkenyl-substituted cyclic anhydride and to its use as a paper additive.