Peroxyester Workup pH Control for Reduced Hydroperoxide Content
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Solution Overview
Problem
Peroxyesters and percarbonates often contain undesirably high levels of hydroperoxide and have poor storage stability, posing regulatory and application challenges.
Innovation Solution
A process that manipulates the reaction mixture pH during the workup by reducing and increasing it to specific ranges, followed by agitation, to reduce hydroperoxide content and enhance storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If standard workup process with washing steps is used, then residual organic hydroperoxide is reduced, but hydroperoxide content remains undesirably high and storage stability is poor
Solution Approach 1:
The patent applies parameter changes by manipulating pH at different stages of the workup process. Specifically, the pH is adjusted to be greater than 6.8 (preferably greater than 7.0, 7.2, or 7.4) during the reducing agent treatment step, and maintained at this level for a specific duration (at least 5 seconds to several minutes). This pH parameter control enables simultaneous achievement of low hydroperoxide content and high storage stability, resolving the technical contradiction between manufacturing precision and reliability.
2Reliability
If pH is increased to greater than 6.8 during reducing agent treatment, then storage stability is improved, but additional process steps are required
Solution Approach 1:
The patent merges the pH adjustment step with the existing reducing agent treatment step. Rather than adding a separate pH adjustment operation, the process integrates pH control into the reducing agent treatment phase, where the reducing agent is applied at pH greater than 6.8. This integration achieves improved storage stability without significantly increasing process complexity, as the pH maintenance is combined with the existing reduction operation.
3Manufacturing precision
If pH is maintained for extended period, then hydroperoxide content is reduced further, but processing time increases
Solution Approach 1:
The patent applies preliminary action by maintaining the pH greater than 6.8 for a specific minimum duration (at least 5 seconds, preferably at least 10 seconds, 30 seconds, 60 seconds, or several minutes) during the reducing agent treatment. This time-limited pH maintenance creates optimal conditions for hydroperoxide reduction without requiring extended processing times. The preliminary establishment of correct pH conditions ensures efficient hydroperoxide removal within a controlled time frame, balancing manufacturing precision with time efficiency.
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 achieves peroxyesters and percarbonates with significantly reduced hydroperoxide content and improved storage stability, maintaining less than 300 ppm initial hydroperoxide and a four-week stability value of 300 ppm or less.
Implementation Method 1
adding a reducing agent to the organic layer after the aqueous layer has been separated in step b), wherein the reducing agent is an agent capable of reducing the organic hydroperoxide to the corresponding alcohol
Data Source
AI summary
The present disclosure relates to a process for preparing a peroxyester or peroxycarbonate comprising: a) reacting tert-butyl hydroperoxide with an acid halide, an acid anhydride, or a haloformate, in the presence of a base, b) separating the aqueous layer after completion of step a), c) adding a reducing agent to the organic layer after the aqueous layer has been separated in step b), wherein the reducing agent is an agent capable of reducing tert-butyl hydroperoxide to the tert-butyl alcohol, d) ensuring that the mixture of step c) has a pH of greater than 6.8 by maintaining or increasing the pH of the mixture of step c), and e) maintaining the pH of greater than 6.8 for at least 5 seconds, wherein the process is characterized in that: i) the mixture of step c) has a pH of less than 6.8 before step d), and in step d) the pH of the mixture of step c) is increased to a pH of greater than 6.8; and/or ii) after completion of step e) the pH is decreased to a pH of less than 6.8.