| Solid-state reaction method at low heat has many advantages, such as few solvent, high selectivity, high output, low energy cost, so it has became a novel synthetic technique for preparing nanometer size inorganic materials. In this paper, nanometer size (NH4)2Ti(PO4)2, Ce1-xTixP2O7 and NH4MnPO4·H2O powders were synthesized via solid-state reaction at low heat. Besides, catalytic performance of (NH4)2Ti(PO4)2 in the synthesis of butyl acetate and thermal decomposition kinetics of nanometer crystalline NH4MnPO4·H2O were also investigated. The paper consists of six chapters.Chapter one: IntroductionCharacteristic and preparation progress of nanometer materials were introduced. Besides, the principle of preparing nanometer inorganic material via solid-state reaction and its advantage were also summarized.Chapter two: Preparation of (NH4)2Ti(PO4)2 via solid-state reaction at low heat and characterizationThe (NH4)2Ti(PO4)2 was obtained via solid-state reaction at low heat when Ti(SO4)2 and (NH4)3PO4·3H2O were used as raw materials. Product and its thermal decomposition products were characterized using TG/DTA, IR, XRD, UV and TEM. The results showed that average particle size of amorphous (NH4)2Ti(PO4)2 obtained at 80℃for 5h was about 40nm. When (NH4)2Ti(PO4)2 was calcined at 900℃for 3h, the nanometer crystalline TiP2O7 with high crystallization, space group Pa-3(205), was obtained, and its average particle size was about 23nm. The product and its thermal decomposition products behaved as excellent UV-shielding materials.Chapter three: Study on (NH4)2Ti(PO4)2 used for catalytic synthesis of butyl acetateThe butyl acetate was synthesized when nanometer size amorphous (NH4)2Ti(PO4)2 was used as catalyst, and glacial acetic acid and n-butanol were used as raw materials. The optimum conditions were obtained via uniform design method. The results showed that the optimum conditions were as follows: molar ratio of acetic acid to butanol was 1.92:1, reaction time was 5.1h, catalyst dosage was 1.4g (7.8%w/w), and esterification yield was 0.99 under the optimum conditions. The catalyst can be prepared via simple technique, and used repeatedly, little equipment cauterization and environmental pollution, so this catalyst would have a bright future for industrial application.Chapter four: Preparation of Ce1-xTixP2O7 powders via solid-state reaction at low heat and study on their UV absorbency.Ce1-xTixP2O7(with x = 0, 0.2, 0.5, 0.7, 0.9, and 1.0) were obtained via solid-state reaction at low heat when Ce(SO4)2·4H2O, Ti(SO4)2 and Na4P2O7·10H2O were used as raw materials. The products and its products calicined were characterized using XRD, TG/DTA, UV and TEM. The results showed that naometer size amorphous Ce1-xTixP2O7 obtained at 100℃behaved as an excellent UV-shielding materials respectively. There into, the CeP2O7 has the most excellent UV-shielding effect, the amorphous state of Ce0.8Ti0.2O7 can keep at higher temperature than CeP2O7. Therefore, the stabilization of the amorphous state of the cerium pyrophosphates was carried out by doping titanium (Ti). This stabilization is a significant improvement, which enables to apply these amorphous pyrophosphates not only to cosmetics and paints, but also plastics and films.Chapter five: Preparation of NH4MnPO4·H2O via solid-state reaction at low heat and characterizationThe nanometer crystalline NH4MnPO4·H2O was obtained when MnSO4·H2O and (NH4)3PO4·3H2O were fully ground via solid-state reaction at room temperature, then mixture was kept at room temperature for 12h, and washed with water to remove soluble inorganic salts and dried at 60℃. Product was characterized using XRD, TG/DTA, IR, UV and SEM. The results showed that average particle size of nanometer crystalline NH4MnPO4·H2O obtained at 60℃with high crystallization, orthorhombic system, space group Pmnm(59), was about 45nm. When NH4MnPO4·H2O was calcined at 600℃and 900℃for 3h respectively, the nanometer crystalline Mn2P2O7 with space group C2/m(12), monclinic system, was obtained, and their average particle sizes were about 22 nm and 61nm respectively.Chapter six: Study on thermal decomposition kinetics of NH4MnPO4·H2OThermal decomposition kinetics of NH4MnPO4·H2O was investigated using thermo-gravimetric-differential thermal analysis (TG-DTA). The results showed that thermal decomposition of NH4MnPO4·H2O at temperature below 600℃occurs in two well-defined steps. The first step is attributed to the desorption of water and ammonia from NH4MnPO4H2O, and the second step is attributed to dehydration of MnHPO4 and formation of Mn2P2O7. Activation energy (E), frequency (A), and mechanism function of each thermal decomposition reaction step are as follows: E = 105.7 kJ/mol, lnA = 24.9 s-1, G(a) = (1-a)-1-1 for reaction(1); and E = 113.6 kJ/mol, lnA=14.5 s-1, G(a) = [1/(1-a)1/3-1]2 for reaction(2).
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