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Study On The Synthesis And Engineering Basis Of 2-Methyl-1,3-Propanediol

Posted on:2008-06-19Degree:DoctorType:Dissertation
Country:ChinaCandidate:H P LiFull Text:PDF
GTID:1101360215477826Subject:Chemical processes
Abstract/Summary:PDF Full Text Request
2-Methyl-1, 3-propanediol(MPO), a successful commercial product, does not only bear an excellent antibacterial and biodegradation features, but also affords the products based on it more peculiar properties. So, the conventional diols which are being widely used now are gradually replaced by MPO in many aspects. However, There are a few overseas reports and even less domestic ones on the preparation of MPO and little information retrieved, concerning the synthesis of MPO based on 2-methyl-propene (i-C4). Hence, as a project (No.511021100) funded by Henan Natural Science Foundation aiming at the demand of national economy development and the fact that the field of Fine Chemical Industry faces to, a new process using isobutene as main material to synthesize 2-methyl-1, 3-Propanediol (MPO) which contains i-C4 gaseous continuous chlorination, hydrolysis of 3-chloro-2-chloromethyl-1-propene and hydrogenation of 2-methlylene-1, 3-propanediol was developed in the thesis. Also, the related synthesis conditions and application groundwork were studied systematically, which is very important technically and practically.Firstly, on the basis of molecular structure of i-C4 and the fine organic synthetic principle, thermodynamic and kinetic analysis were done according to the heat of 2-methylpropene chlorination estimated by means of Benson's and Joback's Group Contribution Method. A tubular flow chlorinator with three jacket tubes and bearing extra parts for enhancing mass and heat transfer was specially designed and manufactured. 3-Chloro-2-chloromethyl-1-propene (CCMP), an intermediate of MPO, was synthesized using the tubular reactor via gaseous continuous chlorination of 2-methylpropene and the structure of CCMP was determined by GC-MS. The results showed that the intensely exothermic problem was resolved in the tubular reactor and the even temperatures distribution came true. The key influence on the selectivity of chlorination and yield of CCMP was examined by numbers of experiments. It was showed that the chlorine and iso-C4 ratio 2.03:1(mol), temperature 50℃and flow of fluid 0.26L.min-1 gave the yield of dichlorobutene over 65% and selectivity 80%.Secondly, the preparation of 2-methylenel, 3-propanediol by alkaline hydrolysis of CCMP in presence of N, N-dimethylformamide (DMF) solvent was studied. The influence of several variables on the hydrolysis reaction was examined by the Orthogonal and single factorial tests. The experimental results showed that at the reflux temperature of 92℃, V(CCMP)/V(OH)=1:5, 10%(w%) of alkali aqueous concentration, m(solvent)/m(CCMP)=20%~25% and the time 6h, the conversion of CCMP reached about 95%. Moreover, the macroscopic hydrolysis kinetics of CCMP under the optimum reaction conditions was also studied. The macroscopic kinetic equation was: Where A is CCMP and B OH. The average apparent activation energy Eαof the hydrolysis process in temperature range of 70℃~90℃was 33.45kJ.mol-1.Thirdly, the final product MPO was synthesized in a self-designed bubble tower reactor under atmospheric pressure in presence of Pd/γ-Al2O3 catalyst. The structure of MPO prepared was verified by IR, QP-5000 GC-MS and GC900. Influences of several variables such as PH value of reactant solution, temperature, time, the amount of catalyst on the yield of product MPO were examined. The optimum hydrogenation conditions were: 60℃, 6h, catalyst 9g, hydrogen flow 0.4L/min and the yield of MPO was over 90%。And more, the experimental densities, viscosities and interfacial tension data of MPO+H2O binary system at 298.15K~367.15K were presented under atmospheric pressure, which Ostwald-Sprengel-type pycnometer used for determination of density, Ubbelohde capillary viscometer for viscosity and Maximum Bubble Method for surface tension. The experimental data were correlated.The results showed that the relationship between MPO's densities and temperature t accord with Francis model: p/g.cm-3=1.032-6.90x10-4t/℃; There is a maximum value of densities in about 70%MPO (wt) under given temperature. The viscosities of MPO accord with Andrade Equation: ln(η/mPa.s)=-14.526+5854.9/T. And, excess molar volumes VE and viscosity deviation△ηwere obtained respectively from experimental data and both the values were negative, which shows that MPO+H2O binary system bears negative deviations from ideal system. Also, the binary mutual parameters△Gij. from Grunberg-Nissan model were obtained by the regression from experimental data and vary as temperatures and concentrations of MPO aqueous solution.The interfacial adsorption of MPO+H2O was positive one and isothermal adsorption curveΓ~c (MPO) was fit for Gibbs formula. Also, Szyszkowski model for MPO+H2O binary system were obtained by the regression from experimental data:...
Keywords/Search Tags:2-Methyl-1,3-propanediol, 2-Methylpropene, Tubular Chlorination reactor, 3-Chloro-2-chloromethyl-1-propene, Viscosity, Thermodynamic properties, Volume properties, Interfacial properties, Kinetics
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