CO2-to-Propylene Process for Controlled Polypropylene Molecular Weight

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Solution Overview

Problem

Existing industrial processes lack a viable method to produce propylene and its polymer polypropylene from carbon dioxide (CO2) on an industrial scale with controlled molecular weight and narrow molecular weight distribution, which are essential for demanding applications.

Innovation Solution

A process involving electrocatalytic reduction of CO2 to methylglyoxal, followed by reduction with sodium borohydride to form 1,2-diol, and subsequent elimination of hydroxide groups to produce propylene, using nickel phosphide catalysts and specific reagents like sodium borohydride and thiocarbonyl or phosphorus compounds, followed by polymerization to achieve controlled molecular weight and properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If current industrial processes are used to produce propylene from CO2, then production can occur on an industrial scale, but the yield is low and molecular weight distribution is uncontrolled

Engineering Contradiction:

ImproveyieldVSAvoidmolecular weight distribution

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs a multi-step process with controlled parameter changes: electrocatalytic reduction parameters (catalyst composition, electrode potential, temperature, pH) are optimized to achieve high yield of methylglyoxal, followed by controlled reduction parameters (sodium borohydride concentration, temperature, time) to achieve complete conversion to 1,2-propanediol with controlled molecular weight distribution. This systematic parameter optimization resolves the contradiction between high yield and controlled molecular weight distribution.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If CO2 is converted to propylene through existing methods, then the process can be implemented, but it lacks sustainability and environmental friendliness

Engineering Contradiction:

ImprovesustainabilityVSAvoidprocess feasibility

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent converts CO2, a harmful greenhouse gas, into valuable propylene and polypropylene products through electrocatalytic reduction. The process uses nickel phosphide catalysts to transform CO2 into methylglyoxal, which is then reduced to 1,2-propanediol and converted to propylene. This approach simultaneously addresses environmental sustainability by sequestering CO2 and provides a feasible manufacturing route to produce polymers with controlled molecular weight distribution, resolving the contradiction between sustainability and ease of manufacture.

Inventive Principle:

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

3Adaptability or versatility

If propylene is produced without controlled molecular weight distribution, then production is simpler, but the polymer properties cannot meet demanding application requirements

Engineering Contradiction:

Improveapplication suitabilityVSAvoidprocess complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the propylene production process into distinct controlled stages: (1) electrocatalytic reduction of CO2 to methylglyoxal using nickel phosphide catalysts with optimized composition ratios, (2) reduction of methylglyoxal to 1,2-propanediol using sodium borohydride under controlled conditions, and (3) conversion of 1,2-propanediol to propylene. Each stage has independently optimized parameters that collectively ensure controlled molecular weight distribution in the final polymer product, making it suitable for demanding applications while maintaining reasonable process complexity through systematic division of steps.

Inventive Principle:

Principle #1Segmentation

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

Enables the production of propylene and polypropylene with a narrow molecular weight distribution and improved physical, mechanical, and chemical properties, resulting in a lower CO2 footprint and suitability for demanding applications.

Implementation Method 1

a) electrocatalytic reduction of the CO2 to generate methylglyoxal (I)

Methodology Applied

Scientific EffectElectrocatalytic reduction: Catalysis

Implementation Method 2

US 2020/0 347 502 A1 likewise describes nickel phosphides for electrochemical reduction of CO2 to hydrocarbons using nickel phosphide nanoparticles

Methodology Applied

Scientific EffectElectrochemical reduction: Electrochemiluminescence

Implementation Method 3

b) reduction of the methylglyoxal (I) from operation a) with a reducing agent to generate the corresponding 1,2-diol (II)

Methodology Applied

Scientific EffectReduction: Reduction

Implementation Method 4

c) elimination of the hydroxide groups of the 1,2-diol (II) from operation b) to generate propylene (III)

Methodology Applied

Scientific EffectElimination reaction: Chemical Bonding

Data Source

PatentUS12624462B2Process for preparing propylene and polypropylene from CO<sub>2</sub>

Publication Date: 2026.05.12 VOLKSWAGEN AG

AI summary

Illustrative embodiment relates to an environmentally friendly process for producing propylene and its polymer propylene from the starting material carbon dioxide CO2.