Purpose

This paper aims to study the thermal oxidation performance of antioxidant additives in ester base oils deeply.

Design/methodology/approach

ReaxFF molecular dynamics was used to simulate the thermal oxidation process of butyl octyl diphenylamine and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate as two antioxidant additives act on the Trimethylolpropane trioleate (TMPTO) base oil. Meanwhile, combining with the infrared spectroscopy characterization results of the thermal oxidation test, this paper provides theoretical support for the development of high-performance synthetic lubricants and their antioxidant additives.

Findings

The results show that butyl octyldiphenylamine easily removes the hydrogen atom on the secondary amine, which promotes the formation of more long carbon chain diene radicals or polyene hydroperoxides from TMPTO. Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate could easily decompose into octadecyl hydroperoxide and 2,6-di-tert-butyl 4-propionylphenol, which could convert into 2-tert-butyl-4-peroxyethyl-6-hydroperoxy-tert-butylphenol in the middle of the thermal oxidation reaction, prompting TMPTO to form more short-chain alkenyl and olefin hydroperoxide or other oxide.

Originality/value

The main change characteristics of base oil molecules are the first thermal decomposition to form oleic acid groups and ethane cyclopropane methyl oleate. Under the action of butyl octyldiphenylamine and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate, the deep oxidation and decomposition reaction are slowed down.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0037/

中文翻译：

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ReaxFF MD研究了TMPTO与抗氧化剂的热氧化机理

目的

本文旨在深入研究酯基油中抗氧化剂的热氧化性能。

设计/方法/方法

ReaxFF分子动力学用于模拟丁基辛基二苯胺和十八烷基3-（3,5-二叔丁基-4-羟基苯基）丙酸酯的热氧化过程，因为两种抗氧化剂均作用于三羟甲基丙烷三油酸酯（TMPTO）基础油。同时，结合热氧化试验的红外光谱表征结果，为高性能合成润滑油及其抗氧化剂的研制提供理论支持。

发现

结果表明，丁基辛基二苯胺可轻松除去仲胺上的氢原子，从而促进由TMPTO形成更长的碳链二烯基或多烯氢过氧化物。3-（3,5-二叔丁基-4-羟苯基）十八烷基丙酸酯可轻易分解为十八烷基氢过氧化物和2,6-二叔丁基4-丙酰基苯酚，可转化为2-叔丁基-4 -过氧乙基-6-氢过氧叔丁基苯酚在热氧化反应的中间，促使TMPTO形成更多的短链烯基和烯烃氢过氧化物或其他氧化物。

创意/价值

基础油分子的主要变化特征是首次热分解形成油酸基团和乙烷环丙烷油酸甲酯。在丁基辛基二苯胺和十八烷基3-（3,5-二叔丁基-4-羟基苯基）丙酸酯的作用下，深度氧化和分解反应变慢。

同行评审

本文的同行评审历史记录可在以下网址获得：https://publons.com/publon/10.1108/ILT-01-2020-0037/