Quinone Methide Antipolymerants for Vinyl Monomers

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Solution Overview

Problem

Unsaturated vinyl monomers in hydrocarbon streams undergo undesirable thermal polymerization, leading to product loss and equipment fouling, with current antipolymerants like dinitro-substituted aromatic compounds being toxic and environmentally harmful.

Innovation Solution

The use of non-toxic 7-cinnamyl substituted quinone methide derivatives as antipolymerants to inhibit polymerization of unsaturated compounds, which are safe and do not produce NOx or SOx emissions, effectively preventing polymerization during processing, transportation, and storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dinitro-substituted aromatic compounds (DNBP) are used as antipolymerants, then polymerization inhibition efficacy is improved, but environmental safety and toxicity are worsened

Engineering Contradiction:

Improvepolymerization inhibition efficacyVSAvoidtoxicity and environmental harm

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical structure parameters of antipolymerants by replacing dinitro-substituted aromatic compounds with quinone methide derivatives. This structural parameter change maintains the polymerization inhibition function while eliminating the toxic nitro groups, thus resolving the contradiction between efficacy and environmental safety

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs quinone methide derivatives that function as effective antipolymerants without the persistent environmental harm of DNBP. These alternative compounds achieve the necessary inhibition effect with reduced environmental persistence and toxicity, allowing for safer disposal and reduced regulatory burden

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Loss of substance

If polymerization is prevented using conventional antipolymerants, then product loss is reduced, but equipment fouling still occurs requiring shutdowns

Engineering Contradiction:

Improvemonomer lossVSAvoidunscheduled shutdown time

Core Design Contradiction:

Loss of substanceVSLoss of time

Solution Approach 1:

The quinone methide derivatives are introduced into the hydrocarbon stream in advance to prevent polymerization before it can occur. This preliminary protective action prevents both product loss and the formation of fouling deposits on equipment, eliminating the need for unscheduled shutdowns

Inventive Principle:

Principle #10Preliminary action

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

Prevents unwanted polymerization of unsaturated compounds, reducing product loss and equipment fouling while being environmentally friendly and safe, without the toxic and regulatory issues associated with existing antipolymerants.

Implementation Method 1

quinone methides are well known in the art as effective free radical scavengers

Methodology Applied

Scientific EffectFree radical scavenging: Chemical Bonding

Data Source

PatentUS9957209B2Use of quinone methides as antipolymerants for vinylic monomers

Publication Date: 2018.05.01 ECOLAB USA INC

AI summary

The present invention generally relates to compounds and methods for inhibiting the radical polymerization of unsaturated compounds, particularly vinyl monomers. More particularly, it relates to the use of cinnamyl quinone methides to inhibit the polymerization of unsaturated hydrocarbon compounds (e.g., vinyl monomers) soluble in organic solvents, particularly hydrocarbon streams.