Sequential Temperature Alkylation for Nonylated Diphenylamine
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Solution Overview
Problem
Existing methods for preparing alkylated diphenylamines face challenges in minimizing unreacted diphenylamine content, leading to product loss and increased costs due to high temperature distillation and excessive use of alkylating agents, with residual alkylating agents having lower reactivity and potential halogenation issues.
Innovation Solution
A process involving consecutive recycling of recovered nonene at sequential two-step temperature reactions, using acid clay as a catalyst to achieve high conversion rates and minimize unreacted diphenylamine, with nonene being used in excess to optimize usage and reduce waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high temperature distillation is used to remove unreacted diphenylamine, then the product purity is improved, but the process cost and energy consumption increase
Solution Approach 1:
The patent changes the reaction parameters by using a two-step temperature process (175-200°C followed by 140-160°C) to optimize the alkylation reaction, achieving high conversion rates and minimizing unreacted diphenylamine to less than 1 wt%, thereby reducing the need for energy-intensive distillation
Solution Approach 2:
The patent converts the potentially harmful effect of residual unreacted diphenylamine into a benefit by using it as a reactant in a second alkylation step with additional nonene, transforming it from a waste product requiring removal into a valuable intermediate that contributes to the final product
2Productivity
If large excess of alkylating agent is used to reduce unreacted diphenylamine, then the conversion rate is improved, but the cost and waste increase
Solution Approach 1:
The patent optimizes the molar ratio of nonene to diphenylamine and implements a two-stage temperature process to achieve high conversion rates with minimal excess alkylating agent, reducing waste while maintaining productivity
Solution Approach 2:
The patent implements a continuous process where unreacted diphenylamine from the first alkylation step is immediately utilized in a second alkylation step, ensuring continuous conversion and minimizing waste of the alkylating agent
3Loss of energy
If recycled alkylating agent is used, then the cost is reduced, but the reactivity decreases due to rearrangement and halogenation
Solution Approach 1:
The patent changes the reaction conditions by using a two-step temperature process and selecting specific catalysts that minimize rearrangement and halogenation of the recycled nonene, thereby maintaining its reactivity for subsequent alkylation reactions
Solution Approach 2:
The patent performs preliminary separation and purification of the recycled nonene to remove halogenated compounds and rearrangement products before reusing it in the alkylation reaction, restoring its reactivity and ensuring reliable performance
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 an alkylated diphenylamine product with less than 1 wt% unreacted diphenylamine, improving nonene usage efficiency and producing a stable, liquid antioxidant suitable for lubricating compositions.
Implementation Method 1
Alkylation of diarylamines, such as diphenylamine, with olefins in the presence of suitable alkylation catalysts
Implementation Method 2
Alkylation of diphenylamine with nonene in the presence of acid clay catalyst
Implementation Method 3
heating the reactor to a first temperature of from about 175° C. to about 200° C. in the presence of acid clay catalyst under reactive conditions for a suitable period of time to alkylate a majority of charged diphenylamine; reducing the reaction temperature to a second temperature of from about 140° C. to about 160° C.
Implementation Method 4
recovering residual nonene from an acid clay catalyzed alkylation reaction of nonene with diphenylamine
Data Source
AI summary
The present invention relates to a process for preparing nonylated diphenylamines which improves nonene usage by recycling and reusing stripped nonene from an earlier process. The process comprising consecutive recycle of recovered nonene is conducted at a sequential two step temperature reaction, namely a more severe temperature followed by a lower temperature. The product prepared by this process is a useful antioxidant for lubricating oil compositions.