Nicotinic Acid Synthesis And Preparation Of Chromium Salts

Nicotinic acid is a kind of important organic synthesis raw materials, and used in a wide range, for example, medicine, food, feed additive and chemical auxiliary, etc. The demands to nicotinic acid are increasing year by year in domestic and international market. Chromium nicotinic acid is a kind of important benefit chromium products. With the development of society and improvement of level of people's life the demands to chromium nicotinic acid are increasing year by year. Nicotinic acid and chromium nicotinic acid is one of the subjects that researcher pay close attention to.The thesis includes four parts: Synthesis process conditions of nicotinic acid with 3-picoline oxided by potassium permanganate that process conditions were further optimized. The synthesis of nicotinic acid used selenium dioxide as oxidant was studied. The kinetics was researched. The recycling use of oxidant was researched. The synthesis of chromium nicotinic acid was studied; the analysis method of product was determined.1. Process conditions of synthesis and the method of purification of products that nicotinic acid through 3-picoline oxided by potassium permanganate was searched. Reaction temperature, the pH of solution, the way of potassium permanganate joined and crystallization condition were further optimized. The yield was up to 88.4%. Selenium dioxide is one of the gentle oxidant having good alternatives. Synthesis of nicotinic acid used selenium dioxide as oxidant was studied. The suitable reaction condition was that the mole ratio of 3-picoline / selenium dioxide was 1:1.6, pyridine was used as solvents, the concentration of 3-picoline was 2mol/L, reaction temperature was 130 ℃, reaction time was 2h, products yield was up to 40.1%. Synthesis of chromium nicotinic acid was carried on. The suitable reaction condition was that the mole ratio of nicotinic acid /sodium hydroxide was 1:1, and the mole ratio of nicotinic acid /chromic was 3.2:1, the concentration of 3-picoline was 3.3mol/L reaction temperature was 73℃, the acceleration of dripping was 7mL/h, the pH of solution was 7.4-7.6 before reacting, the pH of the solution was 6.8-7.0 after reacting. Under this reaction condition, end-resulting products chromium content was 12.35%, average product yield was up to 92.4%.2. The recycling use of oxidant was researched. The suitable reaction condition was that the mole ratio of selenium/ nitric acid was 1:4.2, the concentration of nitric acid was 5.5mol/L, reaction temperature was 95℃, reaction time was 3h, the yield was up to 97.8%.3. Kinetics of oxidation of 3-picoline by selenium dioxide was studied. It was deduced that the reaction follows second-order kinetics in the range condition studied and the relationship between reaction rate constant and temperature wask =1.519×10¹⁵ exp(-136.53×10³/ RT)4. The analysis method of content to chromium nicotinic acid through Atomic Absorption Spectroscopy and oxidation of ammonium persulfate was researched. The method of oxidation of ammonium persulfate was confirmed to be feasible...