Alkane Conversion to Unsaturated Acids via Oxidative Dehydrogenation

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Solution Overview

Problem

The existing processes for partial oxidation of alkanes to unsaturated carboxylic acids, such as acrylic acid, result in high concentrations of saturated carboxylic acid byproducts like propionic acid, which are difficult to separate due to similar boiling points and solubility, leading to product quality issues and economic challenges.

Innovation Solution

Adjusting process conditions and employing selective chemical reactions, including oxidative dehydrogenation and aldol condensation, to convert saturated carboxylic acids into more easily separable or tolerable compounds, using catalysts like mixed metal oxides and co-catalysts, and implementing separate finishing reactors for downstream processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If partial oxidation of alkanes is used to produce unsaturated carboxylic acids, then the production process is simple and cost-effective, but the concentration of saturated carboxylic acid byproducts is high and difficult to separate

Engineering Contradiction:

Improveproduction efficiencyVSAvoidproduct purity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent converts the harmful saturated carboxylic acid byproducts into useful unsaturated carboxylic acids through oxidative dehydrogenation. The saturated acids, which were previously difficult to separate and remove, are now transformed into the desired unsaturated products, turning a purification problem into a production advantage and increasing overall yield.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the chemical state of saturated carboxylic acids from saturated to unsaturated through oxidative dehydrogenation. This parameter change in molecular structure (adding double bonds) fundamentally alters the separation characteristics and allows these byproducts to be converted into valuable products rather than requiring complex separation processes.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional distillation is used to separate saturated and unsaturated carboxylic acids, then the separation process is straightforward, but the separation is ineffective due to similar boiling points

Engineering Contradiction:

Improveseparation simplicityVSAvoidseparation efficiency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

Instead of attempting to separate saturated and unsaturated carboxylic acids through distillation, the patent converts the saturated acids into unsaturated acids through oxidative dehydrogenation. This eliminates the separation problem entirely by transforming the difficult-to-separate byproducts into the desired product type, making the separation task unnecessary.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If extraction using common solvents is used to remove saturated carboxylic acids, then the process is simple, but the extraction is unsuccessful due to similar solubility

Engineering Contradiction:

Improveextraction simplicityVSAvoidextraction efficiency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent converts saturated carboxylic acids into unsaturated carboxylic acids through oxidative dehydrogenation, transforming them from extraction-resistant byproducts into the desired product. This eliminates the need for extraction processes and turns what would be a purification challenge into a production advantage.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Manufacturing precision

If selective partial oxidation is used to improve product quality, then the concentration of desired unsaturated carboxylic acid increases, but the concentration of saturated carboxylic acid byproducts also increases

Engineering Contradiction:

Improveunsaturated carboxylic acid concentrationVSAvoidsaturated carboxylic acid concentration

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent applies oxidative dehydrogenation to convert the saturated carboxylic acid byproducts into unsaturated carboxylic acids. This transforms the harmful saturated acids into useful unsaturated products, simultaneously increasing the concentration of desired product while eliminating the problematic byproducts through chemical transformation rather than simple separation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

Significantly reduces the concentration of saturated carboxylic acids in the final product, improving the purity and yield of unsaturated carboxylic acids, enabling cost-effective production by facilitating easier separation and recovery of valuable byproducts.

Implementation Method 1

Useful chemistries, listed in Table 1 and described further below, include oxidative dehydrogenation (ODH) and aldol condensation reactions.

Methodology Applied

Scientific EffectOxidative dehydrogenation: Oxidation

Implementation Method 2

Useful chemistries, listed in Table 1 and described further below, include oxidative dehydrogenation (ODH) and aldol condensation reactions.

Methodology Applied

Scientific EffectAldol condensation: Chemical Bonding

Data Source

PatentEP1967507B1An improved process for converting alkanes to unsaturated carboxylic acids

Publication Date: 2015.09.23 ROHM & HAAS CO

AI summary

The present invention relates to an improved process for the conversion of alkanes to unsaturated carboxylic acids.