The Effect Of Surfacetants On The Electrooxidation Of 3-picoline To Nicotinic Acid

Electrooxidation product of 3-picoline is nicotinic acid. It is the vitamine which has the simplest configuration and the steadist quality . Nicotinic acid is widely used as the additive of medcine, food and drink, feedstuff, as well as the auxiliary agent. It is the raw material of some dye, the brightener of electroplate, the plant growth regulators, the polymer stabilizer and the antioxidation agent of sensitive material. The methods of synthesis include chemical-oxidation, air catalytic-oxidation and electrooxidation. The chemical-oxidation method was used to synthesizing nicotinic acid by oxidation of 3-picoline with nitric acid and KMnO4 as oxidants. Because of its low yield and high pollution, it was fallen into disuse in industry. The 3-picoline was oxidized by oxygen in air with catalyst. The air catalytic-oxidation methods has not been used. The electrooxidation is green synthesizing method friendly with the environments, which just using electricity and without using oxidant and no pollution to environment.But 3-picoline low solubility in water, it was alkaline, only in the higher acidity can help 3-picoline, of the conduct, and the higher the better. The increase in acidity to bring about separation and purification of the difficulty, and a large number of salts, difficult to handle, and therefore hope to have a material can make 3-picoline in soluble in lower in acidity but higher Solubility, surfactant is such a substance, it is a class at a very low concentration can significantly reduce water surface tension of organic compounds. Surfacetants unique structure of the parents, that is water-and oil-based, in the interface or the surface, with directional or in solution form micelles, it is easy to form a layer on the electrode surface with the orientation film, so that good organic matter Scattered in the electrolyte solution, thus affecting the organic matter in the electrode surface electronic exchange process. Therefore, the surfactant in analytical chemistry, electrochemistry and the application of a broader. In recent years, organic surface active agent in biological and pharmaceutical analysis in the study and application of more and more active. In some systems, chemical analysis, the surfactant can increase sensitivity several times, several times, or even nearly 100 times. Surfactant in the electrochemical system in the use of many. The most commonly used is to join the surfactant in the electrolyte, thus changing the surface of the electrode solution and electrochemical properties, the impact of the proliferation of material and electrochemical reaction. Such system is mainly used surfactant hydrophobic material under test and its role in the static, complex, and so on, so as to achieve electrochemical enhancement purposes.In proton exchange membrane system, with sulfuric acid in the electrolyte solution to support PbO2 electrodes on the 3-picoline electro-oxidation was studied, inspected the cationic surfactant - Cetyltrimethylammonium bromide (CTAB), anion Surfactant - fatty alcohol polyoxyethylene sodium (AES) and SDBS (SDBS), gender surfactant - N, N-dimethyl-Dodecyl betaine (Lycine) , Non-ionic surfactants - sorbitol anhydride Monostearate ester (Span60), polyoxyethylene sorbitol Monostearate ester (Tween60), polyoxyethylene-sorbitol oil ester (Tween80) and octyl Phenol polyoxyethylene (TX-100), such as surfactants to 3-picoline, nicotinic acid oxidation from the impact. CV curve through the measurement to determine the surfactant CTAB, AES, SDBS, Lycine and Span60 the process of accession to the anode is obvious role in promoting and Tween60, Tween80 and TX-100 non-ionic surfactants not promote, And when accession to the concentration of more than critical micelle concentration, CTAB, AES, SDBS and Span60 to anodizing substantial increase in current density. The addition of these Span60 close and higher than the critical micelle concentration of anodizing current density similar to that, and the addition of Lycine 3-picoline of the current density, the rate of increase smaller.And 0.5 mol / L sulphuric acid as the electrolyte support 3-picoline anode of adding CTAB, AES, SDBS, Lycine and Span60 for electrolysis experiments, results showed that in lower concentrations of sulfuric acid to support the electrolyte, and the selectivity of the current efficiency have improved to varying degrees. CV curve measurements identified Span60 the process of accession to the anode is obvious role in promoting, this is probably because Span60 on 3-picoline played a good dispersion, solubilization and wetting electrode, allowing 3 - A Pyridine-electrode in the vicinity has maintained a high concentration is conducive to the formation of nicotinic acid. And non-ionic surfactants Span60 a high degree of industrialization, it will add Span60 in 3-picoline electro-oxidation of the electrical and mechanical systems are designed orthogonal experimental programme, admitted surfactant concentration, 3-picoline / Moore than the sulfate concentration, temperature, anode and electrolytic potential power five factors, each factor choose four different levels, namely, the surfactant Span60 concentration: 0 mol / L, 0.5×10-4mol / L, 1.5×10-4mol / L, 7.5×10-4mol / L; 3-picoline / sulfate concentration than the mole: 0.6, 0.5, 0.47, 0.4, 3-picoline concentration: 0.3, 0.5, 0.7, 0.9mol / L, H2SO4 concentration: 0.5, 1.0, 1.5, 2.25 mol / L; reaction temperature: 15℃, 25℃, 35℃, 45℃. Anode potential: 1.7, 1.8, 1.9, 2.0 V. Electrolysis reaction of all the electricity equivalent of nicotinic acid into the necessary theoretical capacity of 10%, 20% and 30%, 40%. In accordance with the conditions of orthogonal 3-picoline constant potential electrolysis orthogonal experiment. Measured by liquid chromatography electrolyte 3-picoline and nicotinic acid to calculate the amount of nicotinic acid electrolysis generated the current efficiency and selectivity. To determine when to join Span60 electrolysis system the best conditions, namely: 3-picoline / molar concentration of sulphuric acid ratio of 0.4, that is 2.25 mol/LH2SO4 and 0.9 mol / L 3-picoline, add higher than the critical glue Beam concentration or close to the critical micelle concentration Span60, temperature 15℃, anode potential of 1.9 V ~ 2.0V, electrolysis capacity of 10% of its selective up 85.46%, 48.69% for the current efficiency. In selected experimental area, Span60 on 3-picoline power of a clear role in promoting, current density, selectivity and current efficiency has significantly improved, and prospects.Chromium is niacin and niacin trivalent chromium ion formation of chelates. Many studies proved that nicotinic acid chromium glucose tolerance factor is an important component of GTF, the paper on the nicotinic acid and nitric acid in raw materials for the production of chrome the feasibility of chromium niacin, and then examine the various factors affecting the impact of its yield , Of nicotinic acid to determine the best conditions chromium. Under the best conditions to 3-picoline as raw materials for direct oxidation of nicotinic acid, chromium. For direct oxidation of nicotinic acid, chromium, not the law of electrolysis to separate the product but will trivalent chromium salt directly on to the next step of the reaction, reducing the experimental steps so that a simple operation, the final yield was 60.64% And, through infrared spectroscopy and elemental analysis of the product, that the experiment is the purpose of the products.