Synthesis, characterization and catalytic application of H4SiW12O40/MCM-48 in the esterification of methacrylic acid with n-butyl alcohol

A novel environmental friendly catalyst, H4SiW12O40/MCM-48, was prepared by impregnation method. The catalysts were characterized by means of XRD and FT-IR. The synthesis of n-butyl methacrylate catalyzed by H4SiW12O40/MCM-48 was studied with methacrylic acid and n-butyl alcohol as reactants. H4SiW12O40/MCM-48 was an excellent catalyst for the synthesis of n-butyl methacrylate and Keggin structure ofH4SiW12O40 kept unchanged after impregnated on surface of the molecular sieve support. Effects of n（methacrylic acid）： n（n-butyl alcohol）, catalyst dosage, cyclohexane （water-stripped reagent） and reaction time on the yields of the product were investigated. The optimum conditions have been found, that is, molar ratio of acid to alcohol is 1：1.5, mass ratio of catalyst used to the reactant is 1.5%, cyclohexane is 10 mL and reaction time is 1.5h. Under these conditions, the yield of n-butyl methacrylate can reach 73.2%.

Hydrothermal Synthesis and Electrochemical Properties of Amorphous LiMoS2 as a High Capacity Anode Material for Lithium Ion Batteries

The LiMoS： anode material for lithium ion rechargeable batteries were synthesized by a hydrothermal method at 150 ℃. According to our measurements with X-ray diffraction, LiMoS2 was amorphous structure. Electrochemical measurements results showed that LiMoS2 exhibited large lithium storage capacities.

Synthesis of Multifunctional Mn-Doped CdTe/ZnS Core/Shell Quantum Dots

The synthesis of a novel water-soluble Mn-doped CdTe/ZnS core-shell quantum dots using a proposed ultra- sonic assistant method and 3-mercaptopropionic acid （MPA） as stabilizer is descried. To obtain a high luminescent intensity, post-preparative treatments, including the pH value, reaction temperature, reflux time and atmosphere, have been investigated. For an excellent fluorescence of Mn-doped CdTe/ZnS, the optimal conditions were pH 11, reflux temperature 100℃ and reflux time 3 h under N2 atmosphere. While for phosphorescent Mn-doped CdTe/ZnS QDs, the synthesis at pH 11, reflux temperature 100℃ and reflux time 3 h under air atmosphere gave the best strong phosphorescence. The characterizations of Mn-doped CdTe/ZnS QDs were also identified using AFM, IR, powder XRD and thermogravimetric analysis. The data indicated that the photochemical stability and the photolu- minescence of CdTe QDs are greatly enhanced by the outer inorganic ZnS shell, and the doping Mn2＋ ions in the as-prepared quantum dots contribute to strong luminescence. The strong luminescence of Mn-doped CdTe/ZnS QDs reflected that Mn ions act as recombination centers for the excited electron-hole pairs, attributing to the transition from the triplet state （4T1） to the ground state （6A1） of the Mn2＋ ions. All the experiments demonstrated that the surface states played important roles in the optical properties of Mn-doped CdTe/ZnS core-shell quantum dots.

One-bath synthesis of hydrophilic molecularly imprinted quantum dots for selective recognition of chlorophenol

A simple one-bath strategy has been developed to synthesize a novel CdTe@SiO_2@MIP（molecularly imprinted and silica-functionalized CdTe quantum dots,MISFQDs）,in which a silica shell was coated on the surface of CdTe quantum dots （CdTe@SiO_2 QDs） and then a polymer for selective recognition of 4-chlorophenol（4-CP） was constructed on the surface of CdTe@SiO_2 QDs using mercaptoacetic acid as stabilizer,3-aminopropyl-trimethoxysilane（APTES） as functional monomers and tetraethoxysilane（TEOS） as crosslink agent.The structures of CdTe@SiO_2@MIP were analyzed by ultraviolet-visible absorption. Fluorescence,FT-IR spectrum and powder X-ray diffraction.The application and characterization of the CdTe@SiO_2@MIP were investigated by experiments.All results indicated that the CdTe@SiO_2@MIP can selectively recognize 4-chlorophenol.