Synthesis and characterization of diblock copolymer of butadiene and 2-ethyl-2-oxazoline

Ｂｌｏｃｋｃｏｐｏｌｙｍｅｒｓａｓｉｄｅａｌｃｏｍｐａｔｉｂｉｌｉｚｅｒｓｈａｖｅｆｏｕｎｄｗｉｄｅａｐｐｌｉｃａｔｉｏｎｓｉｎｐｏｌｙｍｅｒｂｌｅｎｄｓ.Ｆｏｒｂｌｏｃｋｃｏｐｏｌｙｍｅｒｓｃｏｎｔａｉｎｉｎｇｐｏｌａｒｂｌｏｃｋｓ,ｉｔｓａｄｄｉｔｉｏｎｔｏａｂｌｅｎｄｃｏｎｔａｉｎｉｎｇｐｏｌａｒｃｏｍｐｏｎｅｎｔｓｌｅａｄｓｔｏｔｈｅｄｅｃｒｅａｓｅｉｎｉｎｔｅｒｆａｃｉａｌｔｅｎｓｉｏｎｂｅｔｗｅｅｎｔｈｅｉｍｍｉｓｃｉｂｌｅｐｈａｓｅｓｏｆｔｈｅｂｌｅｎｄ,ｔｈｅｉｎｃｒｅａｓｅｉｎｃ…     

Structures and Vibrational Spectra of C_2 and LaC_2~ Clusters

ＳｔｒｕｃｔｕｒｅｓａｎｄＶｉｂｒａｔｉｏｎａｌＳｐｅｃｔｒａｏｆＣ２ａｎｄＬａＣ＋２Ｃｌｕｓｔｅｒｓ＊ＷＵＺｈｉ－ｊｉａｎ，ＭＥＮＧＱｉｎｇ－ｂｏａｎｄＺＨＡＮＧＳｉ－ｙｕａｎ＊＊（ＣｈａｎｇｃｈｕｎＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄＣｈｅｍｉｓ...     

Structures and stabilities of HPO_2 isomers

The potential energy surface of HPO2 system including eight isomers and twelve transition states is predicated at MP2/6-311++G(d, p) and QCISD(t)/6-311++G(3df,2p)(single-point) levels of theory. On the potential energy surface, cis-HOPO(E1) is found to be thermodynamically and kinetically most stable isomer followed by trans-HOPO(E2) and HPO(O)(C2v, E3) at 10.99 and 48.36 kJ/mol higher, respectively. Based on the potential energy surface, only E1 and E3 are thermodynamically stable isomers, and should be experimentally observable. The products cis-HPOO(E5) and frans-HPOO(E6) in the first-step reaction of HP with O2 can isomerize into isomer E1 that has higher stability. The reaction of OH with PO will directly lead to the formation of isomer E1. The computed results are well consistent with the previous experimental studies.     

Structures and Stability of HNS_2 Isomers

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｎｉｔｒｏｇｅｎ ｓｕｌｆｕｒｃｏｎｔａｉｎｉｎｇｃｏｍｐｏｕｎｄｓｈａｖｅａｔ ｔｒａｃｔｅｄｍｕｃｈａｔｔｅｎｔｉｏｎｉｎｔｈｅｆｉｅｌｄｓｏｆｐｏｌｙｍｅｒｉｃｍａｔｅｒｉａｌｓａｎｄａｔｍｏｓｐｈｅｒｅｃｈｅｍｉｓｔｒｙ .1 4 Ａｎｄｓｏｍｅａｖａｉｌａｂｌｅｅｘｐｅｒｉ ｍｅｎｔａｌａｎｄｔｈｅｏｒｅｔｉｃａｌｉｎｆｏｒｍａｔｉｏｎｗａｓｒｅｐｏｒｔｅｄａｂｏｕｔｔｈｅｓｅｃｏｍｐｏｕｎｄｓｗｉｔｈＨ ｅｌｅｍｅｎｔｏｒｏｔｈｅｒｆｕｎｃｔｉｏｎａｌｇｒｏｕｐｓ…     

Structures and stabilities of HPS_2 isomers

The potential energy surface of HPS2 system containing nine isomers and fifteen transition states is obtained at MP2/6-311++G(d, p) and QCISD(t)/6-311++G(3df, 2p)(single-point) levels. On the potential energy surface, the lowest-lying frans-HSPS(EI) is found to be thermodynami-cally the most stable isomer followed by cis-HSPS(E2) and HP(S)S(C2v, E3) at 3.43 and 14.17 kJ/mol higher, respectively. The computed results show that species E1, E2, E3, stereo HP(S)S(Cs, E4) with PSS three-membered ring, isomers trans-HPSS(E5) and cis-HPSS(E6) which coexist with E4 are kinetically stable isomers. The products E6 and E5 in the reaction of HP with S2 can be isomerized into higher kinetic stable isomer E4 with 65.75 and 71.73 kJ/mol reaction barrier height, respectively. The predicated results may correct the possible inaccurate conclusion in that the product was experimentally assigned as isomer cis-HPSS(E6).     

Adsorption properties and photocatalytic activity of TiO2 and La-doped TiO2

Photocatalysts of TiO₂ and La-doped TiO₂ were prepared by calcining the pure TiO₂ sols and the sols mixed with La(NO₃)₃⋅6H₂O at 873 K, respectively. These photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and N₂ adsorption-desorption isotherms measurement. As results, the BET surface area, pore diameter, mesopore volume and micropore volume slightly increased, while the crystallite size and the phase structure were little affected by lanthanum doping. The equilibrium adsorption of methylene blue (MB) on the photocatalysts were measured in a dark room. The adsorption isotherms were confirmed to fit to the Langmuir theory. Photocatalytic activities of the photocatalysts were studied by employing the photocatalytic degradation of MB in water and degradation of acetaldehyde in air under UV-irradiation using a black light. Kinetic analysis revealed that the rate controlling steps could be the surface reaction of the adsorbed MB on the catalyst surface for MB degradation and the reaction of adsorbed acetaldehyde with the gaseous acetaldehyde for degradation of acetaldehyde, respectively.     

Novel Bis-hydroxymethylation of Imidazole and 2-Methylimidazole

Sincethedevelopmentofsupramolecularchemistrytheheterophaneshavbeenattractinggrowingattentionbecauseoftheirpotentialuseasartificialempesandreceptors,inseif-assembly,innanoscalemachinery,andinprovidinginsightintononcovalentbondinginteractions[1-2].Thoughavarietyofheterophaneswithnovelstructuresandpropenieshavebeenreported,onlyafewarecomposedofinddazole[3-10].4,5-bis(hydroxymethyl)imidazoleanditsderivativesarehighiyimportantintermediatesfortheSynthesisofvariousimidazolophanes,imidazolecrownethers…     

Reaction of 2-alkoxycarbonylmethyl derivatives of δ2-oxazoline and δ2-imidazoline and their tautomers with 4-nitrobenzonitrile N-oxide

It was established that 2-alkoxycarbonylntethylene derivatives of oxazolidine and imidazolidine react readily with 4-nitrobenzonitrile N-oxide; the reaction takes place at the methylidyne carbon atom to give intermediate oximes, which can then undergo cyclization to isoxazoles. Their tautomers —benzimidazole and ² -oxazoline derivatives —react with considerably greater difficulty; in the first case the reaction takes place at a different center, viz., the ring nitrogen atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 681–684, May, 1991.     

Synthesis and Characterization of the Terpolymer of Itaconic Acid with Acrylamide and 2-Acrylamido-2-methylpropanesulfonic Acid

The thermal stability of the polymer is of great significance in paper, ceramics and oil industry1. Conventional polymers such as polyanionic cellulose can not meet high temperature limitations2-4. Aggour5-6 and Collette7 etc. have conducted extensive research on synthesis and characterizations of the copolymer or terpolymer containing 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS). Till now, very few research works have been reported on the terpolymer of itaconic acid (IA), acrylamid…     

Structures and Stability of NHS2 Isomers

Potential energy surface of HNS2 is investigated by means of second-order Moller-Plesset Perturbation theory(MP2) and QCISD(T) (single-point)methods,At final QCISD (T)/6-311 G(3df,2p)//MP2/6-311 G(d,p),level with zero-point vibrational energies included,cis-NHSS is found to be global minimum on the potential energy sufrace,followed by low-lying trans-HNSS ,HN(S)S(C2v).cis-HSNS,cis-NSSN,trans-HSNS,trans-NSSN,and HN(S)S(Cs) by 13.46,66.92,78.25,80.38,81.22,81.38 and 86.40 kJ/mol,respectively.A new high-lying HS(N)S isomer with Cs symmetry is located on the potential energy surface ,The kinetic stabilities of all isomers are predicted.Comprisons are made for HNS2 with its analogues,NHO2,HPS2 and HPO2,The causes that lead to the differences between HNS2 and its analogues are hypervalent capacity of phosphorus and distinct electronegativities of hydrogen,nitrogen and phosphorus.     

Synthesis and Structure of the Complexes of 2-Alkoxycarbonylalkyltin Trichlorides with 2-Salicylideneaminophenol

SinceHutton]developedanovelr0utet0preparationofthe2-alkoxycarbonylalkyltintrichIorides,R'OCOCHRCH,SnCI,(l),lhavereceivedconsiderableattenti0nbecauseofthevarietyofcoordinationgeometriesaboutthetinatom.2-'Previ0usly,wehadre-portedtheadducts0flwithneutraIdonorssuchasDMSO,HMPA,bpyandphen.'-'Inthispaper,wereportthesynthesis0fthecomplexes0flwithnegativebivaIentligandderivedfr0m2-salicylideneamin0phenop(H2L),R'OCOCHRCH,SnClL(R=H,Me,R'=Me,Et,n-Pr,Allyl,n-Bu),andthecrystaIstructureof…     

The [2?+?2?+?2] mechanisms of trimerization of three ethynes and monosilaethylenes

The mechanisms of [2?+?2?+?2] reactions of three ethynes and monosilaethylenes to form benzene and 1,3,5-trisilacyclohexane were studied by ab initio MO methods. The reaction mechanisms were analyzed by configuration interaction/localized molecular orbital/CASSCF calculations. Although the [2?+?2?+?2] reaction of ethyne is typically ??homologous?? concerted, that of monosilaethylene is polarized (ionic-cyclic) one-step reaction. In addition, the aromaticity along the intrinsic reaction coordinate pathway was studied using the index of deviation from aromaticity. Although the transition state of trimerization of ethyne does not have an aromatic nature for the ??- and ??-bonds formation system, the crossing point of the ??-bond formation and ??-bond breaking shows an aromatic nature.     

Isolation and Crystal Structure of 2—Bromoaldisin

INTRODUCTION2-Bromoaldisin was first isolated from the marine sponge Hymeniacidon aldis [1,2]. In the course of our systematic search for bioactive substances from marine organisms, we have studied the marine sponge Phacellia fusca Schmidt and obtained the title compound. Up to now, there is no report on the crystal structure of 2-bromoaldisin. This paper reports the isolation and crystal structure of it. EXPERIMENTALIsolation of 2-bromoaldisinThe sponge, Phacellia fusca Schmidt wa…     

Thermal behavior and effect of SiO2 and PVA-SiO2 matrix on formation of Ni–Zn ferrite nanoparticles

Journal of Thermal Analysis and Calorimetry - The paper presents the synthesis of ZnFe2O4/SiO2, NiFe2O4/SiO2, Ni0.4Zn0.6Fe2O4/SiO2 and Ni0.4Zn0.6Fe2O4/PVA-SiO2 nanocomposites by a modified...     

Synthesis and Characterization of SnO2 One-dimensional Nanostructures

Single-crystalline SnO2 nanowires have been successfully prepared in large scale on Au-coated silicon substrate by heating the mixture of self-made high-purity SnO2 powders and graphite powders at 900℃. Besides the line type nanowires some more features were observed. The products were characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and Raman spectrum techniques. The results indicate that the tin dioxide nanowires have a rutile structure with diameters ranging from 30 to 120 nm and lengths up to several tens of micrometers. The possible mechanism of the growth and reaction for the nanowires was also discussed.     

Synthesis and Structure of 2—Acetylthiophene Thiosemicarbazone

ＳｙｎｔｈｅｓｉｓａｎｄＳｔｒｕｃｔｕｒｅｏｆ２－ＡｃｅｔｙｌｔｈｉｏｐｈｅｎｅＴｈｉｏｓｅｍｉｃａｒｂａｚｏｎｅ￥ＨｕａｎｇＴａｉ－Ｓｈａｎ；ＹａｏＺｈｉ－Ｙａｎｇ；ＺｈｏｕＺｈａｏ－Ｈｕｉ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，Ｘｉａｍｅｎ...     

Electrocrystallization of PrO2 and TbO2−x from alkali hydroxide melts and characterization of the fluorite-related TbO2−x

Single crystals of PrO₂ and of the oxygen deficient fluorite related phase TbO_2−x have been obtained by anodic electrocrystallization from alkaline hydroxide melts containing PrCl₃ and TbCl₃, respectively. Magnetic measurements, X-ray diffraction data and TEM investigations confirm the identity of the products. PrO₂ crystallizes in a fluorite type of structure with a=5.3945(3) Å and shows paramagnetic behaviour with a magnetic moment as expected for Pr⁴⁺ (μ_eff=2.49μ_B, Θ=−109 K, T_N=10 K). According to precession photographs and an examination with an area sensitive X-ray detector, TbO_2−x exhibits a superstructure of fluorite with a pseudocubic subcell with a_f=5.2810(1) Å. This lattice constant is intermediate between those of TbO₂ and Tb₂O₃ (C-type), the same is true for its paramagnetic behaviour (μ_eff=8.58μ_B, Θ=−22 K, T_N=5 K). The supercell was found to be hexagonal with a=25.836(1) Å and c=36.672(2) Å, the symmetry of the intensity distribution being monoclinic. Electron diffraction revealed a cubic cell with a=10.6 Å, space group Ia-3, indicating reduction of the material in the electron beam.     

Preparation and Photocatalytic Characterization of Nanoporous TiO2

Nanoporous TiO2 photocatalysts were prepared by use of controlled drying method with surfactants. The surface area and porous properties are dependent on the chain length of incorporated surfactant cation. The TiO2 materials prepared in the presence of surfactant molecules during the gel formation exhibit much higher photocatalytic activity than that prepared in the absence of surfactants.