On-Site Peracetic Acid Generation Using Triacetin Precursors
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Solution Overview
Problem
Current methods for generating non-equilibrium peroxyacetic acid (PAA) solutions on-site face challenges such as high capital costs, safety hazards, inefficiency in using hydrogen peroxide and acetic acid, regulatory restrictions, and difficulties in maintaining steady-state conditions, which limit their practicality and scalability in industries like food processing and laundry bleaching.
Innovation Solution
A method involving a hydrogen peroxide-acetyl precursor solution, specifically using triacetin as the acetyl precursor, which is soluble in hydrogen peroxide, allowing for the rapid generation of non-equilibrium PAA solutions at the point-of-use without the need for expensive equipment or hazardous materials, and can be used continuously or intermittently, addressing the inefficiencies and regulatory issues of existing methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If equilibrium solutions of PAA are prepared in advance and stored, then PAA can be supplied ready for use, but the product contains large amounts of inert ingredients (water, acetic acid, hydrogen peroxide) resulting in low PAA concentration (1-15%) and requiring large storage areas
Solution Approach 1:
The patent divides the PAA solution into multiple separate components (hydrogen peroxide solution, acetic acid solution, and stabilizer solution) that are stored individually and mixed on-demand at the point of use. This segmentation eliminates the need to store large volumes of low-concentration equilibrium PAA solutions while maintaining the ability to supply PAA ready for use through automated mixing systems.
Solution Approach 2:
The patent prepares the individual component solutions (hydrogen peroxide, acetic acid, stabilizer) in advance and stores them ready for use. These pre-prepared components are then automatically mixed in precise proportions to generate high-concentration PAA on-demand, combining the benefits of advance preparation with high concentration output.
2Quantity of substance
If equilibrium PAA solutions are stored for several days to reach maximum concentration, then adequate PAA concentration is achieved, but this increases storage time requirements and raw material costs since hydrogen peroxide or acetic acid must be present at levels greater than PAA concentration
Solution Approach 1:
The patent pre-prepares stable component solutions (hydrogen peroxide, acetic acid, stabilizer) that can be stored indefinitely without degradation. When PAA is needed, these components are automatically mixed in precise proportions to generate high-concentration PAA immediately, eliminating the several-day storage requirement and the need to maintain excess hydrogen peroxide or acetic acid in the final product.
Solution Approach 2:
The patent changes the chemical parameters by using a stabilizer (such as EDTA or phosphonic acid) that allows the component solutions to be stored at optimal concentrations without premature reaction. This stabilizer prevents catalytic decomposition by metal ions, enabling the components to remain stable until mixing, at which point high-concentration PAA is generated immediately without time loss.
3Stability of the object's composition
If metal chelating agents (HEDP or dipicolinic acid) are added to suppress decomposition, then PAA storage stability is improved, but the amount of PAA that can be applied to foodstuffs is limited due to FDA regulations on these stabilizers
Solution Approach 1:
The patent extracts the metal chelating stabilizer from the final PAA product applied to foodstuffs. Instead of adding stabilizer to the equilibrium PAA solution, the system uses a stabilizer only in the hydrogen peroxide component solution during storage and transport. When the components are mixed on-demand, the stabilizer remains separated or is used in minimal amounts, allowing the final PAA application to foodstuffs to meet FDA regulations while maintaining storage stability of the components.
Solution Approach 2:
The patent introduces an intermediary approach by using alternative stabilizing mechanisms or different stabilizer types (such as phosphonic acids or EDTA at controlled levels) that provide adequate storage stability for the component solutions but can be used in concentrations that comply with FDA food contact regulations. This intermediary solution maintains both storage stability and food safety compliance.
4Stability of the object's composition
If the reaction between hydrogen peroxide and acetic acid is allowed to proceed slowly to form PAA, then PAA is formed with adequate stability, but this requires several days' time before quality confirmation and increases inventory storage requirements
Solution Approach 1:
The patent changes the reaction parameters by controlling the mixing conditions, temperature, and component ratios to optimize the PAA generation rate. By adjusting these parameters, the system achieves both rapid PAA formation (high productivity) and adequate stability, eliminating the need for several-day waiting periods while maintaining quality through controlled reaction conditions and automated monitoring.
5Productivity
If equilibrium PAA solutions greater than 6% PAA are used, then higher disinfection efficacy is achieved, but these products are classified as dangerous (DOT marking required, Hazard Class 5.2) requiring Risk Management Plans and hazardous material shipping fees
Solution Approach 1:
The patent segments the high-concentration PAA into separate stable component solutions (hydrogen peroxide, acetic acid, stabilizer) that are each below hazardous concentration thresholds. These components can be shipped without special hazardous material regulations, and high-concentration PAA is generated on-demand at the point of use through automated mixing, achieving high disinfection efficacy without the regulatory burden of transporting and storing hazardous equilibrium PAA solutions.
Solution Approach 2:
The patent introduces an intermediary system (automated mixing equipment and control system) that generates high-concentration PAA on-demand from stable components. This intermediary approach allows the facility to have high-concentration PAA available for effective disinfection while avoiding the need to store or transport hazardous equilibrium PAA solutions, thereby eliminating DOT markings, Risk Management Plans, and hazardous material shipping fees.
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
This approach enables the efficient and safe generation of high-concentration PAA solutions with reduced raw material usage and regulatory burdens, facilitating their use in various industrial applications, including food processing and laundry bleaching, while avoiding the hazards associated with traditional methods.
Implementation Method 1
They are prepared in advance of delivery, typically by reacting hydrogen peroxide with acetic acid in the presence of a mineral acid catalyst
Implementation Method 2
A metal chelating agent, such as hydroxyethylidene diphosphonic acid (HEDP) or dipicolinic acid, is also introduced to suppress the transition metal cation catalyzed decomposition of peroxygen compounds
Data Source
AI summary
Methods and compositions for the generation of a peroxyacetic acid sanitizer in proximity to the point-of-use are disclosed. These methods comprise introducing a hydrogen peroxide-acetyl precursor solution to water, mixing, and then adding an aqueous source of a alkali metal or earth alkali metal hydroxide. Triacetin is a preferred acetyl precursor and is converted rapidly and with a high conversion rate into peracetic acid. These methods produce solutions with a high level of peracetic acid. Methods for preparing the hydrogen peroxide-acetyl precursor solution are also provided. Also disclosed are solid compositions comprising a liquid acetyl precursor, a water-soluble source of hydrogen peroxide, and a water-soluble source of alkalinity. The solid composition is a freely-flowable solid that is used as a bleaching agent and a stain remover for the treatment of articles such as fabrics, dentures, textile garments, and equipment used in the food and beverage industry.