Preparation Of Nanocarbonates And Their Chemical Reaction Behavior

The strong base such as sodium ethoxide used widely in organic synthesis industry istrendling to be replaced by carbonate, espectively potassium carbonate due to sodiumethoxide with some disadvantages such as severe corrosion, more side reactions andcomplicated isolation of products. However, due to the weak alkalinity, the potassiumcarbonate participated organic rections usually need high temperature, high pressure, longreaction time and so on. The preparation and application of nano materical in organicsysnthesis have attracted more and more attentions recently due to their unique physical andchemical properties. The preparation and application of nano potassium carbonate inorganic synthesis are rare. In this thesis, the preparation and application of nano-K2CO3inorganic synthesis are studied. The main contents and results are as following:1. Nano-K2CO3is prepared in the high frequency resonance machine, and effects onmean size of nano-K2CO3are investigated. The results show that mean size of K2CO3prepared by wet grinding method is smaller than that by dry grinding method, and meansize of nano-K2CO3is also affected by solvents. Protonic organic solvents are morefavorable to reduce mean size of micronano-K2CO3. If0.3%of lauric acid compared withthe amount K2CO3was added to solvents, the mean size of nano-K2CO3can be reduced to98nm, which are the size of75%of particles less than100nm. The results also show thatthe alkalinity of nano-K2CO3is strong enough to replace the strong base such as sodiumethoxide to promote the reaction of diethyl malonate and phenyl chloride in protonicorganic solvents.2. Heterogeneous alkylation reactions of active methylene compounds withhalogenated hydrocarbon are carried out in organic solvents using nano-K2CO3as base, andthe effects on the reaction are investigated. The results show that the reactions are morefavorable in protonic organic solvents, and the reactive activity is affected by the structureof active methylene compounds and halides. For Br, Cl-dihalogenated alkylhalides, activemethylene compounds can selectively react with hydrocarbon bromide. Under50-70℃using nano-K2CO3as base in anhydrous ethanol, monoalkylation product can be preparedwith yield of82-90%, which is higher than that by sodium ethoxide.3. Heterogeneous Williamson reactions of phenolic compounds such as bisphenol Awith halides are studied in organic solvents using nano-K2CO3as base, and the effects onthe reaction are investigated. The results show that the reactions are more favorable inprotonic organic solvents, and the two hydroxy groups reacts with halides stepwisely,which is different from Williamson reactions promoted by traditional strong alkaline. Themonoalkylation product can be selectively prapared by control the reaction condition. Themono phenol ether can be prepared in yeild of88%under proper ratio of starting material in anhydrous ethanol. And the liquid biphenol A epoxy resin can be produced in the yield of95%. The epoxy value is0.4267-0.5324mol/100g, chloride content is0.088-0.372%, whichis reached the technical spectification of the industical. The disadvantigates such as highermaterial consumption, severe environmental pollution in traditional process are overcomed.4. Condensation reaction of active methylene compounds with carbon disulfide arestudied in organic solvents using nano-K2CO3as base, and the effects on the reaction areinvestigated. The results show that the reactions are more favorable in protonic organicsolvents, the reactive activity is affected by the structure of active methylene compounds.Under30-40℃in anhydrous ethanol, the yield of alkylated product is82-90%higher thanthat promoted by KOH. N-methyl-1-methylthio-2-nitroethenamine is prepared from methylisothiocyanate and nitromethane as the main raw materials in the yield of85%wich ishigher than that (50%) in traditional process.5. Heterogeneous oximation reactions of active methylene compounds with ethylnitrite are studied in organic solvents using nano-K2CO3as base, and the effects on thereaction are investigated. The results show that the reactions are more favorable in protonicorganic solvents, and the reactive activity is affected by the structure of active methylenecompounds and reaction temperature. Under10-20℃in anhydrous ethanol, the yield is81-92%, which is higher than that promoted by sodium ethoxide. The isolation of product issimple.