Alkanolamide Production Reducing BHEP By-Product

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Solution Overview

Problem

Existing methods for manufacturing alkanolamides result in the formation of undesirable by-products, particularly bis-hydroxyethyl piperazine (BHEP), which crystallizes and can lead to perceived contamination issues, even if not deleterious, necessitating a reduction in BHEP levels.

Innovation Solution

A method involving the addition of diethanolamine (DEA) to fatty acid at a low rate under non-stoichiometric conditions and applying partial vacuum to reduce BHEP formation, with optimized parameters such as molar ratios, addition rates, and reaction temperatures to limit BHEP levels below 5000 ppm.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional methods are used to manufacture alkanolamides, then production efficiency is maintained, but BHEP by-product levels increase to unacceptable concentrations

Engineering Contradiction:
ImproveBHEP by-product level controlVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies parameter changes by modifying the addition rate of DEA (from conventional high rates to 0.0001-10% per minute), adjusting the molar ratio of fatty acid to DEA (maintaining excess fatty acid), and applying vacuum conditions during reaction. These parameter modifications reduce BHEP formation while maintaining acceptable production efficiency, achieving BHEP levels below 5000 ppm.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by using a dynamic addition rate for DEA rather than batch addition. The low addition rate (0.0001-10% per minute) allows the reaction to proceed dynamically, preventing BHEP dimerization while maintaining continuous production. This dynamic approach balances purity control with productivity.

Inventive Principle:
Principle #15Dynamics

2Productivity

If DEA is added at a high rate to maintain production efficiency, then productivity is improved, but BHEP formation increases significantly

Engineering Contradiction:
Improveproduction efficiencyVSAvoidBHEP by-product formation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies periodic action through controlled, continuous addition of DEA at a low rate (0.0001-10% per minute) rather than batch addition. This periodic/continuous approach allows the reaction to proceed slowly, preventing BHEP accumulation while maintaining steady production flow, thus resolving the contradiction between productivity and by-product formation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements continuity of useful action by maintaining continuous DEA addition at a controlled low rate throughout the reaction process, rather than using intermittent batch addition. This continuous controlled addition ensures steady alkanolamide production while preventing the conditions that lead to BHEP formation, balancing productivity with purity.

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If stoichiometric amounts of fatty acid and DEA are used, then reaction efficiency is optimized, but BHEP dimerization increases

Engineering Contradiction:
Improvereaction efficiencyVSAvoidBHEP contamination level
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating a local excess of fatty acid in the reaction mixture. By maintaining fatty acid in excess of DEA (non-stoichiometric conditions), the local concentration of fatty acid ensures that DEA preferentially reacts with fatty acid rather than dimerizing to form BHEP, thus improving product purity while maintaining acceptable reaction efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements preliminary anti-action by pre-establishing excess fatty acid conditions before DEA addition begins. This preliminary setup prevents BHEP formation from the outset by ensuring DEA is always in a environment where fatty acid is available in excess, counteracting the tendency toward BHEP dimerization before it can occur.

Inventive Principle:
Principle #9Preliminary anti-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

The method effectively reduces BHEP levels to 3000 ppm or below, minimizing crystallization and maintaining the quality of the alkanolamide composition, balancing efficiency with BHEP reduction.

Implementation Method 1

applying at least a partial vacuum to the mixture

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

reacting a fatty acid and diethanolamine (DEA) which results in the formation of low levels of undesirable by-products

Methodology Applied
Scientific EffectCondensation reaction: Chemical Bonding

Data Source

PatentUS8138363B2Process for the production of alkanolamide
Publication Date: 2012.03.20 CRODA AMERICAS LLC

AI summary

The present invention relates to a process for the manufacture of alkanolamide containing compositions, and more particularly to a process of reacting a fatty acid and diethanolamine (DEA) which result in the formation of low levels of undesirable by products, particularly of bis-hydroxyethyl piperazine (BHEP).