Study on Preparation of Diaminonaphthalene by Nitration and Reduction of Naphthalene
|Keywords||l, 8 - diaminonaphthalene 1,5 - diaminonaphthalene High Performance Liquid Chromatography Process optimization Ni / CNFs|
1,8 - diaminonaphthalene, and 1,5-diamino-naphthalene diaminonaphthalene, stars isomers, two very important compounds. 1,8 - diaminonaphthalene is a commonly used reagents, its application is extremely broad, generally as an intermediate for organic synthesis of dyes, mainly used in the production of solvent dyes, such as C. Working Solvent Red 135, C. workers Solvent Orange 60. The 1,5 - Diaminonaphthalene mainly used for the synthesis of 1,5 - naphthalene diisocyanate, also often used as the raw material of organic synthesis, pigments and dyes, pharmaceuticals, pesticides and rubber chemicals, resins, photographic materials and other fine chemical products and intermediates, and its use is also very widely. It is used for the production of 1,5 - di-iso-cyanate naphthalene the raw material compound, and the diisocyanate (MDI, TDI) is the core technology of the polyurethane industry (1,5 - di-isocyanate-naphthalene is used in polyurethane production, an isocyanate component). In this experimental study, mainly around of 1,8 - diaminonaphthalene and 1,5 - diaminonaphthalene synthesis process optimization. First naphthyl nitrification Synthesis two nitro (rich in 1,8 - dinitronaphthalene and 1,5 - dinitro - naphthyl and contain small amounts of other impurities mixture), 1,8 - dinitro-naphthalene and 1, about the 5 - dinitronaphthalene total yield of 87%. With toluene, an organic solvent such as dichloroethane and acetone then be isolated and purified so that it can reach the next reaction of the raw material requirements. In two diaminonaphthalene before the synthesis process optimization, you first need to determine their quantitative analysis method. This paper compares determined by high performance liquid chromatography, and a series of verification test results show that quantitative analysis by high performance liquid chromatography separation for its accuracy, and accuracy . Then, using the single-factor method from the six factors of the solvent, reaction time, temperature, hydrogen pressure, catalyst, and the amount of catalyst diaminonaphthalene of 1,8 - and 1,5 - diaminonaphthalene synthesis process optimization research, and get better results. 1,8 - diaminonaphthalene optimum conditions for the synthesis process is based on aniline as the solvent, with 1,8 - dinitronaphthalene mass ratio of 1:11 of Pt / C as catalyst, the reaction for 24 hours in under 2MPa hydrogen pressure, its 1,8 - diaminonaphthalene yield and selectivity are up to the maximum of 94% and 96.7%, respectively, this yield and selectivity of nearly four percentage points higher than the current level of reported in the literature. Synthesis of 1,5 - diaminonaphthalene more excellent process conditions are to 3G1, 5 - dinitro-naphthalene as a raw material, with aniline as a solvent, 0.1gPt / C as catalyst in the the 1MPa hydrogen reduction reaction of 1.75 hours , the yield and selectivity have reached the maximum of 90.2% and 91.8%, respectively. In the process of the optimization of the synthesis process of two diaminonaphthalene, in order to improve the yield and selectivity of the synthesis, will buy the Pt / C catalyst and homemade Ni / CNFs, Pd / C, and Ni / C catalyst applications in the reaction, wherein the catalytic effect of the former three are good. Thereafter, the above four catalyst is a series of characterization and analysis of the impact of the catalyst structure of its catalytic activity.