Preparation Of Magnetic Organic Solid Base With Miniemulsion Polymerization

With enhancement of awareness about environmental protection and the development of green chemistry, contemporary society pay more and more attention to the environment-friendly new catalytic processes. Traditional homogeneous liquid base catalyst is corrosive, has a complexsive subsequent separation process, and is easy to produce large amounts of waste liquid, which can not meet the repuirement of environment-friendly. This problem can be solved by the application of heterogeneous solid base catalyst. Compared with inorganic solid base catalyst, the organic solid base catalyst has the stable active component and uniform base strength. To solve the contradictions of small particles solid catalyst between high catalytic activity and low recovery rate, magnetic features can be given to the solid catalyst. Therefore, a new solid base was perpared by miniemulsion polymerization——magnetic organic solid base, and the properties of magnetic solid base were characterized.Firstly, oleic acid and undecylenic acid co-modified superparamagnetic Fe₃O₄ particles was prepared by chemical coprecipitation, XRD analysis showed that Fe₃O₄ particles are inverse spinel structure, and Fe₃O₄ magnetic particles have an average particle size of about 9nm. The Oily Fe₃O₄ particle with monolayer adsorption of organic acids, good lipophilicity and magnetic response was achieved, under the condition that the reaction temperature is 70?, the molar ratio of organic acid to Fe³⁺ is 20%, and oleic acid molar content of organic acids is 14 to 41%.Secondly, the 4-CMS/St miniemulsion was prepared by the ultrasonication method, and the miniemulsion droplet size and size distribution was analysis by dynamic light scattering techniques. A miniemulsion with an average diameter as low as 99 nm and a polydispersity index of 0.12 was achieved, under the condition that the mass ratio of 4-CMS to St is 1, the concentration of SDS is 10 mg/m L, ultrasonic time is 24 min, ultrasonic power is 400 W and the mass ratio of HD to monomer is 5%. The stability of the miniemulsion decrease with incerase the mass ratio of 4-CMS/St, and Ostwald ripening may be the prime reason for the instability of 4-CMS/St miniemulsion.Thirdly, preparation of P?4-CMS/St? fonctional polymer microspheres with miniemulsion copolymerization was investigated, and the preparation process was optimized by monomer conversion and particle size and size distribution. P?4-CMS/St? fonctional polymer microspheres with an average diameter as low as 71 nm and a polydispersity index of 0.10 was achieved, under conditions that the dosage of 4-CMS and St are both 4.75 g, the concentration of sodium dodecyl sulfate is 10g/L, the time of ultrasonic is 30 min with a 400 W duty, potassium peroxodisulfate is 0.12 g, the amount of divinylbenzene is 0.50 g and the reaction is kept at 70? for 4h.Fourthly, inorganic-organic magnetic polymer composite microspheres ?Fe₃O₄/P?St/4-CMS?? was prepared by miniemulsion polymerization, and the preparation process of magnetic polymer composite microspheres was optimized by particle size and coated rate. Fe₃O₄/P?St/4-CMS? particle with an average diameter 89 nm and narrow size distribution was achieved, under conditions that the amount of ferrofluid with 50% magnet is 3.0g, the concentration of surfactant is 10g/L, the mass ratio of DVB to monomer is 20%, and the mass ratio of HD to monomer is 5%.Fifthly, the law of quaternization was explored by ammoniating P?St/4-CMS? polymeric particle with trimethylamine, pyridine, tri-n-butylamine, N,N-dimethylaniline and N,N-Dimethyl ethanolamine reagent. The magnetic organic solid base was prepared by ammoniating Fe₃O₄/P?St/4-CMS? with trimethylamine, and this base is a strong quaternary ammonium alkali. The properties of magnetic organic solid base are as following: magnetic content is 46.3%, saturation magnetization is 27.5emu/g, the average particle size is 97 nm, exchange capacity is 1.372 mmol/g and the base strength of Hammett value is 17.2¹8.4.