Rice Bran Wax Oxidation for Lower Acid Number Ester Oxidates

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Solution Overview

Problem

Existing methods for producing rice bran wax oxidates result in high acid numbers, typically exceeding 70 mg KOH/g, which are undesirable for certain applications, and require additional esterification steps, making the process economically inefficient.

Innovation Solution

A process involving the oxidation of rice bran wax with a specific mixture of chromium trioxide and sulfuric acid under controlled conditions to achieve an acid number between 45 mg KOH/g and 70 mg KOH/g without additional esterification, by limiting the proportion of multiple esters formed from polyhydric alcohols and aliphatic carboxylic acids to less than 5 wt.%, and optimizing reaction parameters such as temperature and stirring speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If chromic acid oxidation is used to lighten rice bran wax, then color stability is improved, but acid number increases excessively

Engineering Contradiction:
Improvecolor stabilityVSAvoidacid number
Core Design Contradiction:
Illumination intensityVSQuantity of substance

Solution Approach 1:

The patent applies parameter changes by carefully controlling the oxidation conditions including the chromic acid to wax ratio (0.5-2.0:1), temperature (20-100°C), and time (0.5-24 hours) to achieve the desired balance between lightening effect and acid number control. By adjusting these parameters, the process produces oxidates with acid numbers in the range of 10-70 mg KOH/g, resolving the contradiction between color improvement and acid number control.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If additional esterification steps are added to reduce acid number, then acid number is reduced, but process complexity increases

Engineering Contradiction:
Improveacid numberVSAvoidprocess complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent extracts or removes the need for additional esterification steps by directly controlling the oxidation process to produce oxidates with inherently suitable acid numbers. The oxidation process itself is optimized to yield products with acid numbers between 10-70 mg KOH/g, eliminating the requirement for separate esterification units and reducing overall process complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Illumination intensity

If oxidation conversion is increased to improve lightening effect, then color stability is improved, but ester group conversion exceeds desired range

Engineering Contradiction:
Improvelightening effectVSAvoidester group conversion
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent employs feedback control by monitoring and adjusting oxidation conditions based on the desired ester group conversion range (50-90%). The process parameters including chromic acid dosage, temperature, and reaction time are optimized to maintain conversion within this range, ensuring both adequate lightening effect and controlled acid number without over-oxidation.

Inventive Principle:
Principle #23Feedback

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 process produces rice bran wax oxidates with controlled acid numbers and improved color stability, eliminating the need for additional esterification steps and enhancing product consistency and usability for various applications.

Implementation Method 1

The oxidation of fossil and non-fossil natural waxes with chromic acid has been known since the beginning of the 20th century... Oxidation with chromic acid essentially involves the cleavage of wax esters and the in-situ oxidation of the resulting wax alcohols to wax acids.

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentEP4045599B1Light rice bran wax oxidates with a high ester content
Publication Date: 2025.12.03 CLARIANT INT LTD

AI summary

The invention relates to rice bran wax oxidates with an average acid value, to a process for their production and to their use for agricultural or forestry purposes, as an additive in plastics processing, in care products, in printing inks and/or in paints, and to saponified rice bran wax oxidates produced by saponifying the claimed rice bran wax oxidates.