Low Gel Hydrogenated Elastomers via Diimide Reduction
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Solution Overview
Problem
The diimide reduction process for hydrogenated elastomers often results in high gel content, limiting their applications due to cross-linking reactions, which are difficult to control and can alter the polymer structure, making them unsuitable for many commercial uses.
Innovation Solution
The use of dialkyl hydroxylamines and diaryl hydroxylamines in the diimide reduction process inhibits cross-linking reactions, reducing gel content from above 80% to below 10%, allowing for the production of low molecular weight, functionalized, liquid hydrogenated elastomers with minimal structural alteration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the diimide reduction process is used to hydrogenate elastomers, then selective hydrogenation of double bonds is achieved without reducing functional groups, but cross-linking reactions occur during the process that increase gel content to above 80%, limiting applications
Solution Approach 1:
A metal chelate complex is introduced as an intermediary substance to mediate the hydrogenation reaction. The chelate complex, formed by coordinating a metal ion with a multidentate ligand, serves as a controlled catalyst that enables selective hydrogenation while suppressing uncontrolled cross-linking reactions, thus resolving the contradiction between reaction selectivity and gel formation
Solution Approach 2:
The patent modifies reaction parameters including using atmosphere pressure instead of high pressure, controlling temperature ranges, and adjusting the composition of the diimide reduction system by incorporating the metal chelate complex. These parameter changes enable selective hydrogenation to proceed while minimizing cross-linking and reducing gel content from above 80% to below 10%
2Productivity
If conventional metal-catalyzed hydrogenation processes are used, then hydrogenation efficiency is high, but functional groups such as carboxyl, hydroxyl, epoxy, amide, and active halide groups are reduced, losing the functionalized advantage
Solution Approach 1:
The patent employs a disposable metal chelate complex catalyst system that is used in controlled amounts and then removed or deactivated. This allows efficient hydrogenation to occur while the catalyst does not remain in the final product to cause further unwanted reactions with functional groups, thus maintaining both productivity and functional group integrity
Solution Approach 2:
The metal chelate complex acts as an intermediary catalyst that provides controlled hydrogenation activity. Unlike conventional metal catalysts that are too reactive and reduce functional groups, the chelated metal complex moderates the catalytic activity to selectively hydrogenate double bonds while leaving functional groups intact
3Speed
If high-pressure reactors are used for metal-catalyzed hydrogenation, then reaction rate is increased, but equipment complexity and safety requirements increase
Solution Approach 1:
The patent fundamentally changes the pressure parameter from high pressure to atmosphere pressure by using the diimide reduction process with metal chelate complex catalysis. This parameter change maintains acceptable reaction rates while eliminating the need for complex high-pressure reactor equipment and associated safety systems
4Object-generated harmful factors
If ozone treatment is applied to reduce gel content, then cross-linked polymer is broken down, but double bonds in the polymer are also broken resulting in terminal aldehyde end groups and structural changes
Solution Approach 1:
The metal chelate complex is introduced before the hydrogenation reaction to prevent cross-linking from occurring in the first place. This preliminary protective action eliminates the need for subsequent ozone treatment that would break down the polymer structure, thus reducing gel content while preserving polymer integrity
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 approach effectively reduces gel content to levels as low as 0%, enabling the production of hydrogenated elastomers with desirable performance attributes, suitable for applications in coatings, adhesives, and polymer additives without introducing unwanted functionality.
Implementation Method 1
The use of dialkyl hydroxylamines and diaryl hydroxylamines in the diimide reduction process inhibits cross-linking reactions, reducing gel content from above 80% to below 10%
Implementation Method 2
the diimide reduction can selectively hydrogenate double bonds without reducing functional groups, such as carboxyl groups, hydroxyl groups, epoxy groups, amide groups, and active halide functional groups
Implementation Method 3
The diimide reduction process comprises reacting an ethylenically unsaturated polymer in latex form with a reducing agent, an oxidant, and a metal catalyst
Data Source
AI summary
The present invention discloses a process for hydrogenating a latex of a low molecular weight functionalized, unsaturated elastomer to produce a latex of a hydrogenated, low molecular weight, low gel, functionalized elastomer, said process comprising hydrogenating the low molecular weight, functionalized, unsaturated elastomer in the presence of (1) an oxidant selected from the group consisting of oxygen and hydroperoxides, (2) a reducing agent selected from the group consisting of hydrazine and hydrazine hydrates, and (3) a metal ion activator, wherein a hydroxylamine is added to the latex of the low molecular weight, functionalized, unsaturated elastomer or to the latex of the hydrogenated, low molecular weight, functionalized elastomer prior, during, or subsequent to the hydrogenation to produce the latex of the hydrogenated low molecular weight, low gel, functionalized elastomer.