Calcium Hypochlorite PCM Admixture for Low-Chlorate Metathesis
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Solution Overview
Problem
Existing aqueous hypochlorite solutions, particularly calcium hypochlorite, are unstable and prone to self-reactivity, leading to the formation of hazardous chlorates and perchlorates, which pose health risks and increase transportation and storage costs due to safety regulations, limiting their use as a metathesis feedstock.
Innovation Solution
A stoichiometric admixture of calcium hypochlorite with a phase change material (PCM) is used to reduce self-reactivity, allowing safe storage and transportation, and the metathesis process produces a more stable sodium hypochlorite solution with reduced chlorate and perchlorate levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If calcium hypochlorite is used as a metathesis feedstock, then sodium hypochlorite can be produced, but self-reactivity leads to formation of hazardous chlorates and perchlorates
Solution Approach 1:
The patent uses a soluble coating material (hydrated alkali metal salt) as an intermediary substance that mediates between calcium hypochlorite and water. This coating material controls the rate at which water interacts with calcium hypochlorite, preventing rapid self-reaction while still allowing controlled metathesis reaction to produce sodium hypochlorite. The coating acts as a buffer that modulates the chemical reactions.
Solution Approach 2:
The patent changes the physical and chemical parameters of calcium hypochlorite by coating it with a soluble material. This coating modifies the surface properties, water solubility, and reaction kinetics of calcium hypochlorite, transforming it from a highly reactive substance into a controlled-release feedstock that produces sodium hypochlorite with minimal chlorate and perchlorate formation.
2Ease of manufacture
If calcium hypochlorite is stored and transported, then it can be used as feedstock, but safety regulations increase transportation and storage costs
Solution Approach 1:
The soluble coating material serves as a protective intermediary layer that reduces the self-reactivity of calcium hypochlorite during storage and transportation. This coating acts as a safety barrier that prevents spontaneous decomposition while still allowing the material to be handled and transported according to standard safety regulations, thereby reducing costs.
Solution Approach 2:
The patent applies a soluble coating to calcium hypochlorite in advance of storage and transportation. This preliminary action of coating stabilizes the material before it enters the supply chain, ensuring that safety issues are addressed proactively rather than reactively, and allowing standard transportation and storage protocols to be used.
3Loss of substance
If hypochlorite concentration is increased, then transport cost is reduced, but instability and disproportionation rate increase
Solution Approach 1:
The patent performs preliminary stabilization by coating calcium hypochlorite with a soluble material before it undergoes metathesis reaction. This pre-treatment ensures that when the material is later converted to sodium hypochlorite and concentrated, the product maintains improved stability and reduced disproportionation rates even at higher concentrations, enabling cost-effective transport.
Solution Approach 2:
The soluble coating material changes the reaction parameters of the metathesis process, producing sodium hypochlorite with lower residual ionic strength and improved stability characteristics. This parameter change allows the production of concentrated hypochlorite solutions that are more stable than conventionally produced solutions, reducing transport costs without sacrificing stability.
4Duration of action of stationary object
If hypochlorite is stored for extended periods, then supply continuity is improved, but disproportionation into chlorates and perchlorates increases
Solution Approach 1:
The patent applies a soluble coating to calcium hypochlorite in advance, which controls the reaction kinetics during subsequent storage and use. This preliminary stabilization allows the material to be stored for extended periods as calcium hypochlorite (which is more stable than sodium hypochlorite) and only undergoes controlled conversion to sodium hypochlorite when needed, minimizing disproportionation and chlorate/perchlorate formation during storage.
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 admixture results in a safer, more stable sodium hypochlorite solution with lower chlorate and perchlorate concentrations, facilitating its use as a metathesis feedstock and reducing transportation and storage costs while ensuring compliance with safety regulations.
Implementation Method 1
A stoichiometric admixture of calcium hypochlorite with a phase change material (PCM) is used to reduce self-reactivity
Implementation Method 2
a phase change material (PCM) is used to reduce self-reactivity
Implementation Method 3
the metathesis process produces a more stable sodium hypochlorite solution
Data Source
AI summary
The present invention relates to a family of very stable aqueous hypochlorite products and methods for reducing the self reactivity of Ca(OCl)2.