Synthesis of some new bis-3,4-dihydropyrimidin-2(1H)-ones by using silica-supported tin chloride and titanium tetrachloride

Silica-supported tin chloride and titanium tetrachloride were prepared by the reaction of tin chloride and titanium tetrachloride with activated silica gel in refluxing toluene.These solid acids have been employed as the catalysts for the synthesis of bisdihydropyrimidin -2(1H)-ones from aromatic dialdehydes,1,3-dicarbonyl compounds and urea at 90℃under solvent-free conditions.

Communication A convenient trifluoroacetylation of amines with trifluoroacetic acid and titanium tetrachloride

In the past years,trifluoroacetylation has been widely used for protecting func-tional groups.For example,trifluoroacetyl can act as an effective blocking group ofhydroxyl and amino substituents in the reactions of a 1-halo-2-hydroxyl-3-amino sugarwith cholesterol or cyclodecanol.Furthermore,the conversion of the basic aminogroup to less basic amido group by trifluoroacetylation provides a good chromatographyseparation method of amines,e.g.cis-,trans-1,2-diaminocyclohexane can be separatedcompletely,via trifluoroacetylation by GLC technique.

Preparation of TiCl4 with the Titanium Slag Containing Magnesia and Calcia in a Combined Fluidized Bed

This paper describes a new method for producing TiCl4 by chloridizing materials of high content CaO and MgO, in which a combined fluidized bed is used as a reactor to avoid agglomeration between particles caused by molten CaCl2 and MgCl2. The combined fluidized bed consists of at least a riser tube and a semi-circulating fluidized bed. Two kinds of high titanium slag, in which the total mass content of CaO and MgO is 2.03% and 9.09% respectively, are employed to examine the anti-agglomeration effect and the conversion of the materials when the temperature ranges are between 923.15K and 1073.15K, gas apparent velocity 0.7--1.1m.s-1, and inlet amount of solid materials is 4.6-7.0kg·h^-1. It is found that the anti-agglomeration effect in the combined fluidized bed is satisfactory and the new method can achieve a TiCl4 production capacity of 14.0-75.4t·m^-2·d^-1 in relation to 25.0-- 40.0t·m^-2·d^-1 from the conventional bubble bed. Furthermore, low-temperature chloridization, for example, at 923K or 973K, can also be used to produce TiCl4 and avoid agglomeration.

SYNTHESIS OF 1H，1＇H BIS（BENZ－△~4－IMIDAZOLINE）2，2＇－SPIRO－TITANIUM DICHLORIDE

New model compound 1H, 1' H-Bis (benz-△￣4-imidazoline) 2,2'-spiro-titanium dichloride was prepared and the structure of the compound was determined by 1R, us and elementary analysis.

Preparation of TiCl_4 with multistage series combined fluidized bed

In order to solve the agglomeration problem in TiCl4 preparation,a new test in a multistage series combined fluidized bed was studied on a pilot scale.The pilot plant can make full use of titanium slag with a high content of MgO and CaO as the feedstock.Several experimental parameters such as chlorine flow and reaction temperature were discussed and the morphology and components of reaction product were analyzed.According to the results,the conversion rate of TiO2 is up to 90%.It is found that the combined fluidized bed has good anti-agglomeration ability because the accumulation of MgCl2 and CaCl2 on the surface of unreacted slag was carried out of the reactor.

Influence of TiCl_4 treatment on performance of dye-sensitized solar cell assembled with nano-TiO_2 coating deposited by vacuum cold spraying

Titanium tetrachloride (TiCl4) treatment was employed to TiO2 coating deposited on fluoride-doped tin oxide (FTO) conducting glass and indium oxide doped tin oxide (ITO) conducting glass, respectively. The nano-crystalline TiO2 coating was deposited using a composite powder composed of polyethylene glycol (PEG) and 25 nm TiO2 particles by vacuum cold spraying (VCS) process. A commercial N-719 dye was used to adsorb on the surface of TiO2 coating to prepare TiO2 electrode, which was applied to assemble dye-sensitized solar cell (DSC). The cell performance was measured under simulated solar light at an intensity of 100 mW·cm-2. Results show that with an FTO substrate the DSC composed of a VCS TiO2 electrode untreated by TiCl4 gives a short-circuit current density of 13.1 mA·cm-2 and an open circuit voltage of 0.60 V corresponding to an overall conversion efficiency of 4.4%. It is found that after TiCl4 treatment to the VCS TiO2 electrode with an FTO substrate, the short circuit current density of the cell increases by 31%, the open-circuit voltage increases by 60 mV and a higher conversion yield of 6.5% was obtained. However, when an ITO substrate is used to deposit TiO2 coating by VCS, after TiCl4 treatment, the conversion efficiency of the assembled cell reduces slightly due to corrosion of the conducting layer on the ITO glass by TiCl4.

Sm/TiCl_4 (cat.) system-mediated intermolecular and intramolecular reductive coupling reactions of ketones with esters

Sm/TiCl4 system could well integrate the high reactivity of samarium（Ⅱ） and high deoxygenation capacity of low valent titanium within one system. In this paper, the intermolecular and intramolecular reductive coupling reactions of ketones with esters mediated by metallic samarium （Sm） and a catalytic amount of titanium tetrachloride （TiCl4） were successfully developed. A series of substituted ketones and cyclic β-keto-esters were prepared in moderate to good yields under reflux and neutral conditions.

Separation of Impurity Vanadium from TiCl_4 by Means of Adsorption

The possibility and extent of the separation of impurity vanadium in titanium tetrachloride by means of adsorption with molecular sieves were studied. As ascertained by the experimental results, the adsorption of VOCl3 onto molecular sieve internal surface was controlled by the intraparticle diffusion of the molecules. Although all of the three kinds of molecular sieves used are competent for removing vanadium from titanium tetrachloride, type 4 A behaves more effectively than the others under the same conditions. After adsorption for nine stages, the concentration of vanadium in the product becomes as less as that of industrial standard level.

Low-valent titanium induced reductive cyclization of nitro compounds and aliphatic ketones:facile synthesis of 3,4-dihydro-(2H) -1,2,4-benzothiadiazine-1,1-dioxides

The intermolecular reductive cyclization of o-nitrobenzene-sulfonamides with aliphatic ketones induced by TiCl4/Sm system was studied and a series of 3, 3-disubstituted-3,4-dihydro(2H)-1,2, 4-benzothiadiazine-1,1-dioxides were synthesized in moderate to high yields under mild and neutral conditions.

Synthesis and characterization of Li_4Ti_5O_(12) via a hydrolysis process from TiCl_4 aqueous solution

Spinel-type lithium and titanium composite oxide Li4TisO12 was successfully synthesized via a novel hydrolysis method followed by calcination using titanium tetrachloride （TIC14） and lithium hydroxide （LiOH.H2O） as raw materials. Three major factors, including LiOH con- centration, LiOH dosage, and hydrolysis temperature were studied for optimizing the synthetic conditions to obtain a phase-pure Li4Ti5012. The physical and electrochemical properties of samples were characterized by X-ray dif- fraction （XRD）, thermogravimetric analysis （TGA）, fourier transform infrared spectroscopy （FT-IR）, scanning electron microscopy （SEM）, and constant current discharge-charge test. The FT-IR results indicate the presence of [TiO6] octahedra. The SEM images show that the Li4Ti5O12 pre- cursor obtained is an amorphous solid with an irregular and rough morphology. It is revealed that the phase-pure spinel Li4Ti5O12 powders with well crystallization and regular morphology can be obtained by calcining the precursor at 800 ℃ for 6 h. The constant current discharge-charge tests indicate that the Li4TisO12 material delivers an excellent cycling ability, maintaining 93.8 % of its initial specific capacity after 60 cycles at a current density of 0.5C.

TiCl_4 assisted formation of nano-TiO_2 secondary structure in photoactive electrodes for high efficiency dye-sensitized solar cells

A new kind of photoactive electrodes with nanocrystalline TiO2(nano-TiO2)secondary structure is successfully prepared via a simple method of adding a small amount of TiCl4 2-propanol solution in conventional nano-TiO2 paste to form micro-sized nano-TiO2 aggregates.The benefits of this special structure include improved optical absorption,increased light scattering ability,and enhanced electron transport and collection efficiency.Dye-sensitized solar cells(DSCs)based on these photoactive electrodes show improved performance.The power conversion efficiency of the cells can be increased from 5.03%to 7.30%by substituting 6μm conventional nano-TiO2 thin film with the same thickness of as-prepared nano-TiO2 aggregates film in the photoactive electrodes.A higher power conversion efficiency of the cells can be obtained by further increasing the thickness of the nano-TiO2 aggregates film.