Sodium Hydrosulphite Stabilization via Benzoic Acid Additives

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Solution Overview

Problem

Sodium hydrosulphite is prone to spontaneous combustion and decomposition, leading to the formation of toxic gases and classification as a flammable substance, requiring special handling and transportation precautions, which limits its use and stability, especially in the presence of water.

Innovation Solution

A process involving the mixing of sodium hydrosulphite with 4-aminobenzoic acid, 4-hydroxybenzoic acid, or 4-alkyl benzoic acid and ammonium or alkaline-earth salts of oxalic acid, along with optional ammonium or alkaline carbonates and tripolyphosphates, to enhance stability and prevent auto-ignition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If sodium hydrosulphite is stored in barrels or closed metal containers, then transportation and storage are enabled, but the temperature rises rapidly leading to spontaneous combustion and formation of toxic gases

Engineering Contradiction:

Improvethermal stabilityVSAvoidspontaneous combustion

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary substance (stabilizer) that mediates between the sodium hydrosulphite and the harmful decomposition reaction. The stabilizer absorbs or inhibits the decomposition process, preventing the autocatalytic temperature rise that leads to spontaneous combustion, thus enabling safe storage and transportation without requiring special hazardous material handling.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical composition parameters of the sodium hydrosulphite by adding specific stabilizing agents. This parameter change (composition modification) alters the thermal decomposition behavior, raising the ignition temperature and preventing the rapid temperature increase that occurs in pure sodium hydrosulphite, thereby eliminating the spontaneous combustion hazard.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If water is present in sodium hydrosulphite, then the dihydrate form is formed, but this releases heat and acidity which sustains further decomposition

Engineering Contradiction:

Improvewater contentVSAvoidheat release and acidity

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful effect of water (which causes heat release and sustained decomposition) into a beneficial situation by adding stabilizers that prevent the harmful decomposition pathway. The stabilizer allows water to be present without triggering the autocatalytic decomposition, thus converting the potentially harmful water-hydrosulphite interaction into a stable system that can be safely stored.

Inventive Principle:

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

3Reliability

If hydrosulphite is classified as a flammable substance, then safety regulations are enforced, but handling and transportation become complex and costly

Engineering Contradiction:

ImprovesafetyVSAvoidhandling complexity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts or removes the hazardous property (flammability) from the sodium hydrosulphite by adding stabilizers that prevent spontaneous combustion. By eliminating the self-heating and ignition characteristics, the substance is reclassified from a hazardous flammable material to a stable chemical, thereby removing the need for complex handling and transportation regulations while maintaining safety.

Inventive Principle:

Principle #2Taking out (Extraction)

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 stabilization process significantly increases the thermal stability of sodium hydrosulphite, preventing auto-ignition and decomposition, allowing for safe transportation and storage without special safety measures, and maintaining high purity and reactivity, thus removing it from hazardous substance classification.

Implementation Method 1

The decomposition reaction is exothermic and the temperature increase that occurs favours the further decomposition of the remaining salt, according to an autocatalytic mechanism

Methodology Applied

Scientific EffectExothermic reaction: Exothermic Reaction

Implementation Method 2

adding a stabilizing mixture, in solid phase or in solution, comprising agents which are known to have stabilising action and, optionally, further agents

Methodology Applied

Scientific EffectHeat absorption: Absorption (EM radiation)

Data Source

PatentEP3793936B1Process for the stabilisation of hydrosulphite

Publication Date: 2024.10.09 ESSECO SRL

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AI summary

A process for the production of hydrosulphite is described, which provides the mixing of said hydrosulphite with one or more acids chosen among 4-aminobenzoic acid, 4-hydroxybenzoic acid or 4-methylbenzoic acid and with an alkaline salt of oxalic acid. Optionally, a compound is added, chosen among one or more alkaline carbonates and one or more alkaline tripolyphosphates. Advantageously, the components added to hydrosulphite make up a percentage ranging between 0.1 and 20% by weight of the total hydrosulphite. A formulation is also described, containing sodium hydrosulphite and between 0.1 and 20% by weight of a mixture containing: one or more acids chosen among 4-aminobenzoic acid, 4-hydroxybenzoic acid or 4-methylbenzoic acid; an alkaline salt of oxalic acid and possibly one or more alkaline carbonates; one or more alkaline tripolyphosphates.