Acetic Acid Conversion to Isobutene via Mixed Oxide Catalyst

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Solution Overview

Problem

The commercial production of acrylic acid and methacrylic acid generates substantial amounts of acetic acid as a byproduct, which is difficult and costly to remove, leading to yield losses and undesirable properties in the final polymerization products.

Innovation Solution

Converting the byproduct acetic acid into isobutene using a ZnxZryOz mixed oxide catalyst, which can then be further processed into value-added products such as methacrylic acid, isoprene, methyl tertiary butyl ether, ethyl tertiary butyl ether, butylated hydroxytoluene, or isooctane, thereby addressing the need for a renewable source-based method and improving process economics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional distillation methods are used to remove acetic acid from crude acrylic acid, then acetic acid content is reduced, but yield loss of acrylic acid increases

Engineering Contradiction:
Improveacrylic acid purityVSAvoidacrylic acid yield
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The invention extracts and removes acetic acid from the crude acrylic acid stream using extraction distillation or liquid-liquid extraction methods, achieving effective separation while minimizing acrylic acid losses compared to conventional distillation

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediary substance (extractant) that selectively interacts with acetic acid to facilitate its removal from the acrylic acid mixture, enabling separation without direct thermal contact that causes acrylic acid degradation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If extensive purification methods are used to remove acetic acid to achieve glacial acrylic acid specifications, then product purity is improved, but process complexity and cost increase

Engineering Contradiction:
Improveacrylic acid purityVSAvoidpurification process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention employs extraction distillation or liquid-liquid extraction as a targeted purification step that efficiently removes acetic acid without requiring multiple sequential purification stages, thereby simplifying the overall process while achieving glacial acrylic acid specifications

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the separation mechanism from thermal distillation to extraction-based separation, fundamentally altering the process parameters and enabling effective acetic acid removal with simpler equipment and lower operational complexity

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If acetic acid is removed to less than 0.1 percent by weight to produce glacial acrylic acid, then product quality is improved, but yield loss becomes substantial

Engineering Contradiction:
Improveacrylic acid purityVSAvoidacrylic acid yield
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention uses selective extraction methods that target acetic acid molecules specifically, allowing removal to below 0.1 percent by weight specifications while recovering and retaining the majority of acrylic acid, thus achieving high purity with minimal yield loss

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention employs an extractant intermediary that forms selective complexes with acetic acid, enabling ultra-trace removal of acetic acid without requiring excessive processing that would otherwise cause substantial acrylic acid losses

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enables the production of biobased isobutene and value-added chemicals, enhancing the overall economics of acrylic acid and methacrylic acid production while minimizing yield losses and improving catalyst stability and efficiency.

Implementation Method 1

Converting the byproduct acetic acid into isobutene using a ZnxZryOz mixed oxide catalyst

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentUS9156746B2Use of byproduct acetic acid from oxidative methods of making acrylic acid and/or methacrylic acid
Publication Date: 2015.10.13 ARCHER DANIELS MIDLAND CO

AI summary

Processes are described for improved utilization of the byproduct acetic acid universally produced in various oxidative processes for making acrylic acid and methacrylic acid, wherein at least a portion of the byproduct acetic acid is converted to isobutene and optionally to one or more further value-added products which may be prepared from isobutene.