锗钨酸催化合成水杨酸异戊酯

Isoamyl salicylate was synthesized by using germanotungtic acid as catalyst.The effects of the amaunt of catalyst,the molar ratio of salicycic acid of isoamy l alcohol,the reaction temperature and the reaction time on the yield of ester w ere studied.The optimum reaction conditions were 1.3∶100 (mass ratio) of cataly st to reactants,1∶2.5 (molar ratio) of acid to alcohol,135～153℃ being satisfa ctary reaction temperature and reaction time suitable being 3h.Under such condit ion,the yield of ester was up to 94%.Germanotungtic acid catalyst can be used re peatedly.     

Effects of shell composition,dosage and alkali type on the morphology of polymer hollow microspheres

Polymer hollow microspheres were prepared by performing alkali treatment on the multilayer core/shell polymer latex particles containing carboxyl groups. Effects of the shell composition and dosage as well as alkali type on the morphology of the microspheres were investigated. Results showed that in comparison with acrylonitrile(AN) and methacrylic acid(MAA), using butyl acrylate(BA) as the shell co-monomer decreased the glass transition temperature(T_g) of shell effectively and was beneficial to the formation of uniform and big hollow structure. Along with the increase of the shell dosage, the alkali-treated microspheres sequentially presented porous and hollow morphology, and the size of microspheres increased, while the hollow diameter increased first and then decreased, and the maximum hollow ratio reached 39.5%. Furthermore, the multilayer core/shell microspheres had better tolerance to NH_3·H_2O than to NaOH. When the molar ratio of alkali to methacrylic acid(MR_(alkali/acid)) for Na OH ranged from 1.15 to 1.30 or MRalkali/acid for NH_3·H_2O ranged from 1.30 to 2.00, the regular polymer hollow microspheres could be obtained.     

Selective oxidation of propane to acrylic acid over mixed metal oxide catalysts

The effects of metal atomic ratio, water content, oxygen content, and calcination temperature on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid have been investigated and discussed. Among the catalysts studied, it was found that the MoVTeNbO catalyst calcined at a temperature of 600 ℃ showed the best performance in terms of propane conversion and selectivity for acrylic acid under an atmosphere of nitrogen. An effective MoVTeNbO oxide catalyst for propane selective oxidation to acrylic acid was obtained with a combination of a preferred metal atomic ratio （Mo1V0.31Te0.23Nb0.12）. The optimum reaction condition for the selective oxidation of propane was the molar ratio of C3H8 ：O2 ： H2O ： N2 = 4.4： 12.8 ： 15.3 ： 36.9. Under such conditions, the conversion of propane and the maximum yield of acrylic acid reached about 50% and 21%, respectively.     

SYNTHESIS OF 1,2-ACEANTHRYLENEDIONE THROUGH ACYLATION OF ANTHRACENE WITH OXALYL CHLORIDE

Acylation of anthracene and oxalyl chloride in the presence of anhydrous AlCl3 was investigated. Pure 1,2-aceanthrylenedione, which is used as new functional macromolecule, was prepared by extraction and recrystallation. The structure of 1,2-aceanthrylenedione was identified by measure of melting point, GC/MS, FTIR and 1↑HNMR analyses. The influences of various parameters, such as solvent, dosage of catalyst, molar ratio of anthracene to oxalyl chloride, reaction temperature, and reaction time were studied. The anhydrous AlCl3 was found to catalyze the reaction with high yeild and good selectivity. When the reaction temperature is 303K, reaction time is 5h and molar ratio of anthracene to oxalyl chloride is 1：2, the yield and selectivity of 1,2-aceanthrylenedione is 83.8 % and 92.3% respectively.     

SYNTHESIS OF SOAP-FREE ACRYLIC HYDROSOLS

Poly(methyl methacrylate/ethyl acrylate/acrylic acid) hydrosols were prepared by employing soap-freepolymerization, and (acrylic acid/butyl acrylate) oligomer was used as the polymeric surfactant The effect of reactioncondition on the morphology and particle size of the hydrosols was investigated. The minimum amount of acrylic acid in thehydrosols is 2%. The maximum weight average molecular weight (M_w) of polymer that assures soap-free emulsionconversion into hydrosol is about 1.2×10~5-1.3×10~5. The particle transforming process was investigated, and an obviouschange of particle diameter and morphology was observed.     

Effects of Zr/Ti molar ratio in SO42-/ZrO2-TiO2 calcined at different temperatures on its surface properties and glucose reactivity in near-critical methanol

Effects of Zr/Ti molar ratio in SO42-/ZrO2-TiO2 solid acid catalyst calcined at different temperatures on its surface properties and catalytic activity were thoroughly investigated in this paper. The physicochemical characteristics of prepared samples were determined by N2 adsorptiondesorption, XRD, NH3-TPD and XPS techniques, respectively. It was found that the crystallization temperature of the samples increased after the combination of ZrO2 and TiO2; and phase transformations from the anatase to the rutile of TiO2 species and the tetragonal to the monoclinic of ZrO2 species were effectively suppressed at higher temperature. The sample with a Zr/Ti molar ratio of 3/1 calcined at 450℃ showed the highest surface area and the most acid sites among all the tested samples. The acid site densities of samples were relatively closed to each other if they were calcined at the same temperature, however, decreased with the calcination temperature. The result indicates that the sulfur content in samples is a crucial factor to control the acid site density. Calcining the sample at 650℃ and higher temperatures resulted in a significant desorption of sulfate ion on the samples. The synthesized samples were evaluated as a potential catalyst for glucose conversion under the near-critical methanol conditions (200℃/4 MPa). The results suggested that the relatively weaker acid sites of the catalyst were more favorable for the accumulation of methyl glucosides, while the moderate acid sites were responsible for the formation of methyl levulinate. The catalytic activity for methyl levulinate production almost increases linearly with the catalyst acid site density. The catalyst deactivation is due to the loss of sulfate ion and the two catalysts with Zr/Ti molar ratios of 3/1 and 1/3 could effectively alleviate the deactivation caused by sulfate solution in the reaction medium and can be reused after calcination with the reuse rate of over 90% in terms of the methyl levulinate selectivity.     

In situ carbon nanotube synthesis by the reduction of NiO/γ-Al_2O_3 catalyst in methane

The synthesis of carbon nanotubes (CNTs) via chemical vapour deposition of methane on NiO/γ-Al2O3 catalyst has been investigated.The reduction behavior of NiO/γ-Al2O3 by methane was studied using thermogravimetric (TG) and X-ray diffraction (XRD) techniques.It was found that the NiO supported on γ-Al2O3,was reduced to Ni0 in methane atmosphere in the temperature range of 710-770℃.The catalytic activity of NiO/γ-Al2O3 for CNTs synthesis by in situ chemical vapour deposition of methane during the reduction was also investigated.Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the CNTs produced at various reduction temperatures.The results indicated that the reduction temperature exhibits obvious influence on the morphology and the yield of CNTs.CNTs with the diameter of about 20 nm were obtained at reduction temperature of 750℃,and higher reduction temperature (such as 800 and 850℃) led to an increase in CNTs diameter and a decrease in CNTs yield.     

In situ carbon nanotube synthesis by the reduction of NiO/γ-Al2O3 catalyst in methane

The synthesis of carbon nanotubes (CNTs) via chemical vapour deposition of methane on NiO/γ-Al2O3 catalyst has been investigated. The reduction behavior of NiO/γ-Al2O3 by methane was studied using thermogravimetric (TG) and X-ray diffraction (XRD) techniques. It was found that the NiO supported on γ-Al2O3, was reduced to Ni⁰ in methane atmosphere in the temperature range of 710--770 ℃. The catalytic activity of NiO/γ-Al2O3 for CNTs synthesis by in situ chemical vapour deposition of methane during the reduction was also investigated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the CNTs produced at various reduction temperatures. The results indicated that the reduction temperature exhibits obvious influence on the morphology and the yield of CNTs. CNTs with the diameter of about 20 nm were obtained at reduction temperature of 750 ℃, and higher reduction temperature (such as 800 and 850 ℃) led to an increase in CNTs diameter and a decrease in CNTs yield.     

Preparation of Carbon Nanotubes with High Yield and Narrow Diameter Distribution from C2H2 over LaCu0.2Ni0.8Ox

Carbon nanotubes (CNTs) were prepared by decomposition of C2H2 over newly developed LaCu0.2Ni0.8Ox in the temperature range from 600 to 850℃. The effect of the reaction temperature on the yield of CNTs was investigated in detail. At 680℃,the yield of CNTs reaches 17g/g.catal, or so. The morphology of CNTs was examined by TEM. The diameter of CNTs rangs from 9 nm to 14 nm.     

强烈阳极氧化法快速制备多孔氧化铝模板

In the electrolyte of oxalic acid/alcohol/aqueous solution, highly-ordered porous anodic aluminum oxide(AAO) template was fabricated by hard anodization. The surface morphology and the structure of AAO template were characterized by Field-Emission Scanning Electron Microscope(FE-SEM) and XRD, respectively. The effects of different factors including alcohol type, ratio of alcohol to water, and oxalic acid concentration on the ordering degree and pore diameter of AAO template were investigated. Under the glycol to water ratio of 1∶1(by volume) with an oxalic acid concentration of 0.5 mol·L^-1, and voltage at 160 V, the obtained AAO template was hexangular arrangement with pore diameter of 80 nm and pores spacing of 120 nm, the growth rate was 51.9 μm·h^-1.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.