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Copper Chloride (copper + chloride)
Selected AbstractsChemInform Abstract: Direct Synthesis of Bicyclic Guanidines Through Unprecedented Palladium(II) Catalyzed Diamination with Copper Chloride as Oxidant.CHEMINFORM, Issue 38 2008Claas H. Hoevelmann Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Copper stimulates human oral fibroblasts in vitro: a role in the pathogenesis of oral submucous fibrosisJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 8 2001C. Trivedy Abstract: Copper is implicated in the pathogenesis of several fibrotic disorders. Areca nut has been shown to have a high copper content and areca chewing is associated with oral submucous fibrosis (OSF). The effects of copper on human oral fibroblasts were investigated in vitro. Human oral fibroblasts were incubated with copper chloride (CuCl2) at concentrations ranging from 0.01 ,M to 500 ,M for 24 h, and in vitro cell proliferation was assayed by incorporation of tritiated,thymidine; soluble and non-soluble collagen synthesis was assayed using tritiated-proline. Addition of copper chloride at concentrations ranging from 0.1 ,M to 50 ,M increased the collagen synthesis by the oral fibroblasts compared with growth without copper (P<0.05). The addition of copper chloride neither increased the synthesis of non-collagenous proteins by the fibroblasts nor influenced their proliferation rate. We conclude that copper upregulates collagen production in oral fibroblasts. This appears to be concentration dependent, with peak collagen synthesis at 50 ,M CuCl2. These in vitro results taken together with the recent findings of copper in oral biopsies from OSF subjects support the hypothesis that copper in areca nut acts as a mediator of OSF. [source] Diblock copolymers based on allyl methacrylate: Synthesis, characterization, and chemical modificationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2007Rodrigo París Abstract Different diblock copolymers constituted by one segment of a monomer supporting a reactive functional group, like allyl methacrylate (AMA), were synthesized by atom transfer radical polymerization (ATRP). Bromo-terminated polymers, like polystyrene (PS), poly(methyl methacrylate) (PMMA), and poly(butyl acrylate) (PBA) were employed as macroinitiators to form the other blocks. Copolymerizations were carried out using copper chloride with N,N,N,,N,,N, -pentamethyldiethylenetriamine (PMDETA) as the catalyst system in benzonitrile solution at 70 °C. At the early stage, the ATRP copolymerizations yielded well-defined linear block copolymers. However, with the polymerization progress a change in the macromolecular architecture takes place due to the secondary reactions caused by the allylic groups, passing to a branched and/or star-shaped structure until finally yielding gel at monomer conversion around 40% or higher. The block copolymers were characterized by means of size exclusion chromatography (SEC), 1H NMR spectroscopy, and differential scanning calorimetry (DSC). In addition, one of these copolymers, specifically P(BA- b -AMA), was satisfactorily modified through osmylation reaction to obtain the subsequent amphiphilic diblock copolymer of P(BA- b -DHPMA), where DHPMA is 2,3-dihydroxypropyl methacrylate; demonstrating the feasibility of side-chain modification of the functional obtained copolymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3538,3549, 2007 [source] Examination of pigments on Thai manuscripts: the first identification of copper citrateJOURNAL OF RAMAN SPECTROSCOPY, Issue 8 2008Katherine Eremin Abstract Samples from Thai manuscripts dated to the 18th to 20th century were analyzed by Raman spectroscopy and Fourier-transform infrared spectroscopy (FTIR) to determine the pigments used. This suggested a change in palette from the 18th to 20th century, with use of imported pigments in the later manuscripts. In the 18th century, the main green used was an organic copper salt, which was replaced by emerald green and mixtures of Prussian blue with gamboge, chrome yellow and zinc yellow (zinc potassium chromate). Chrome yellow was used in addition to gamboge in one later 19th century manuscript. Similarly, indigo in the 18th century manuscripts was replaced by Prussian blue and then synthetic ultramarine in the 19th century manuscripts. Lead white was the main white pigment in all but one manuscript, which contained huntite, a magnesium calcium carbonate. Huntite also occurred in mixtures with other pigments in two other manuscripts. In all the works studied, red lead, vermilion and red earth were used for red, orange and pink shades and red earth in brown areas. The organic copper salt used in the 18th century gave good FTIR spectra but could not initially be matched with any published compound. X-ray diffraction (XRD) suggested this was a copper citrate phase, and examination of the literature showed that the FTIR spectra matched those published for a hydrated copper citrate. Raman spectra were obtained from this organic copper salt, which showed close agreement with those obtained from synthetic copper citrate. Copper citrate has not been identified previously as an artist's material, although its use has been postulated on the basis of historical texts. Minor copper formate and/or copper chloride were also identified by XRD and scanning electron microscopy (SEM) in some green samples containing copper citrate. Copyright © 2008 John Wiley & Sons, Ltd. [source] The effect of copper(II) on the thermal and mechanical properties of poly(vinyl alcohol)/silica hybridPOLYMER ENGINEERING & SCIENCE, Issue 8 2009Juan Li A novel copper-poly(vinyl alcohol) (PVA)/silica complex was prepared and its chemical structure, thermal, and mechanical properties were studied. The results showed that the crystallinity of PVA first increased and then decreased by the addition of copper chloride, whereas, the thermal decomposition temperature increased dramatically. For PVA/silica hybrid, the decomposition temperature associated with the removal of water molecules in PVA chains was 262°C. But the temperature increased to 361°C when the content of copper chloride was 2 wt%. The intelligent electronic tensile tester was used to investigate the mechanical properties of these complexes. The results suggested that the tensile strength of the complexes is improved with negligible decrease in the plasticity. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source] Modulation of the Aerobic Oxidative Polymerization in Phenylazomethine Dendrimers Assembling Copper ComplexesCHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2010Dr. Takane Imaoka Abstract The aerobic oxidative polymerization of phenol derivatives can provide poly(phenylene oxide)s, which are known as engineering plastics. This oxidation can be carried out with atmospheric oxygen molecules as the oxidizing reagent in the presence of copper complexes as the catalyst; however, stoichiometric or excess amounts of bases are also generally required. By using a phenylazomethine dendrimer complexed with several equivalent amounts of copper chloride, the additive (base)-free polymerization of 2,6-difluorophenol was successful with a very small amount of the catalyst (0.7,mol,% of copper for the monomer) because the dendrimer was composed of many Schiff base units, affording a base and catalyst (copper complex) condensed reaction field. The resulting polymer was nearly linear and the molecular weight was very high. When the equimolar amount of the copper complex in one dendrimer molecule was increased, the polymer obtained under this reaction condition was rather branched, resulting in a higher glass transition temperature. [source] Synthesis of block copolymers by combined ultrasonic irradiation and reverse atom transfer radical polymerization processesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2004Mustafa Degirmenci Abstract A two-step procedure based on ultrasonic irradiation and reverse atom transfer radical polymerization (RATRP) for the synthesis of block copolymers is described. In the first step of the procedure, a stable chlorine-end-capped polymer is formed upon the ultrasonic irradiation of poly(methyl methacrylate) (PMMA) in dry benzene in the presence of a copper chloride/2,2,-bipyridine catalyst. Heating the system to 110 °C initiates the polymerization of the second monomer, styrene, and this results in the formation of the block copolymers. The degradation behavior of PMMA under ultrasonic irradiation has also been studied. The agreement of the experimentally obtained molecular weights and theoretical molecular weights and the unimodal shapes of the gel permeation chromatography curves of the block copolymers indicate the controlled nature of the RATRP process initiated by polymeric radicals formed by sonication. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 534,540, 2004 [source] | |||||||||||||