红色基RL的合成工艺改进

详细研究了红色基RL(对硝基邻甲苯胺,简称RL)的合成工艺,对传统的合成工艺进行了改进,通过用乙酐作氨基保护试剂,混酸硝化,酸性水解等分步操作合成了RL。与传统方法相比,采用乙酐作氨基保护试剂,高温酰化,减少了乙酐用量;用混酸硝化,增强了硝化能力,提高了收率。分别研究了乙酐用量、反应时间、反应温度以及混酸配比对RL收率及熔点的影响规律,得到了反应的较佳条件。采用乙酐酰化分步合成法,RL总收率为56·4%(以邻甲苯胺计),氨基值为91·26%。

Improvement of synthetic process for red base RL

The synthesis of red base RL (4-nitro-2-toluidine,hereinafter abbreviated as RL) was studied in detail.Some improvements were made which were different from the traditional synthesis method.RL was synthesized with acetic anhydride as the acylating agent via stepwise reactions:acylation,nitration and hydrolysis.Compared with the traditional synthesis method,the consumption of acetic anhydride was reduced,because the acylation temperature was higher with acetic anhydride functioning as the acylating agent,and the nitration capability became stronger when the mixed acids were used,resulting in an increased yield via the present method.The effect of the amount of acetic anhydride,reaction time,reaction temperature and the ratio of mixed acids on the yield was investigated and a better reaction condition was acquired.The total yield of RL was 56.4% (based on o-toluidine) with an amino value of 91.26%.