IDENTIFICATION AND USE: Chromium dioxide is a brown-black tetragonal powder. It is used in magnetic recording tapes; as catalyst. Magnetic particles used as solid support in immunoassay. HUMAN EXPOSURE AND TOXICITY: The clinical and hygienic studies performed at the antimonite ore extraction mines in Yakutia revealed that the workers were exposed to high concentrations of polymetallic dusts, containing chromium dioxide, antimony, arsenic and their compounds. Eleven percent of the workers exhibited dust bronchitis, changes in the blood, and immune reactivity indices. A patient with progressive systemic sclerosis and high levels of serum IgE developed multiple papules at/on an area of non-sclerotic skin. Histologic examination of the papule revealed the typical features of scleroderma. For several years, the patient had been working on polishing watches with an abrasive agent composed mainly of aluminum, chromium dioxide, and silica. ANIMAL STUDIES: Rats were exposed by inhalation to chromium dioxide (CrO2) dust at design concentrations of 0, 0.5 (stabilized and unstabilized, respectively) or 25 mg per cu m (stabilized) for 6 hr day-1, 5 days week-1 for 2 years. No dust-exposure-related pathological changes were observed, other than lung lesions, in all exposed rats. There were no significant differences in pulmonary response between unstabilized and stabilized CrO2 at the 0.5 mg per cu m exposure level. The lungs showed minute dust deposition in the alveoli adjacent to the alveolar ducts, but maintained an intact general architecture. The pulmonary responses satisfied the biological criteria for a nuisance dust. At 25 mg per cu m, dust deposition was sharply confined to the alveoli in the alveolar duct region. Alveolar walls enclosing dust-laden macrophage (dust cell) aggregates were thickened with hyperplastic Type II pneumocytes and slightly collagenized fibrosis. Alveoli adjacent to the terminal bronchioles were lined with bronchiolar epithelium (alveolar bronchiolarization). In addition, lungs showed foamy macrophage response, cholesterol granulomas, alveolar proteinosis, and minute fibrotic pleurisy. These pulmonary lesions occurred predominantly in female rats. Of 108 female rats, six developed keratin cysts and two had cystic keratinizing squamous cell carcinoma (CKSCC). None of 106 male rats had either a keratin cyst or a CKSCC. The lung tumors developed from metaplastic squamous cells in the areas of alveolar bronchiolarization in the alveolar duct region. The lung tumors were well differentiated and devoid of characteristics of true malignancy. The CKSCC is an experimentally-induced, unique tumor type and is different from the type of spontaneous lung tumor seen in man or animals.
/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Inorganic acids and related compounds/
[EN] PROCESS FOR PREPARING 2,3,3,3-TETRAFLUOROPROPENE<br/>[FR] PROCÉDÉ DE PRÉPARATION DE 2,3,3,3-TÉTRAFLUOROPROPÈNE
申请人:DAIKIN IND LTD
公开号:WO2010021406A1
公开(公告)日:2010-02-25
The present invention provides a process for producing 2,3,3,3-tetrafluoropropene including the step of dehydrofluorinating 1,1,1,2,3-pentafluoropropane, wherein 1,3,3,3-tetrafluoropropene and 1,1,3,3,3-pentafluoropropane are supplied together with 1,1,1,2,3-pentafluoropropane to a reactor containing a catalyst to simultaneously perform dehydrofluorination reaction and isomerization reaction. According to the process of the present invention, 2,3,3,3-tetrafluoropropene (HFO-1234yf) can be efficiently produced by effectively using the by-products of the dehydrofluorination reaction.
METHOD FOR CARRYING OUT OXIDATION REACTIONS USING INDUCTIVELY HEATED HEATING MEDIUM
申请人:FRIESE Carsten
公开号:US20110301363A1
公开(公告)日:2011-12-08
The invention relates to a method for carrying out an oxidation reaction for producing a product by heating a reaction medium containing a reactant and oxygen or an oxygen carrier in a reactor, wherein the reaction medium is brought into contact with a solid heating medium which may be heated by electromagnetic induction, which is surrounded by the reaction medium. The heating medium is heated by electromagnetic induction using an inductor, wherein an oxidation reaction is carried out on the first reactant to give a product and the product is separated from the heating medium. The inductor preferably generates an alternating field with a frequency in the range 1 to 100 kHz, preferably in the range 10 to 80 kHz and in particular up to 50 kHz.
The vaporization of LaCrOsub 3}(s) and samples of the composition LaCrOsub 3} + Lasub 2}Osub 3} was investigated in the temperature range of 1,887--2,333 K by Knudseneffusionmassspectrometry using Knudsen cells made of tungsten lined completely with iridium. The species Cr(g), CrO(g), CrOsub 2}(g), and LaO(g) were identified in the vapor. Their partial pressures were determined by calibration
Studies on some salicylaldehyde Schiff base derivatives and their complexes with Cr(III), Mn(II), Fe(III), Ni(II) and Cu(II)
作者:S.A. Abdel-Latif、H.B. Hassib、Y.M. Issa
DOI:10.1016/j.saa.2006.09.013
日期:2007.7
synthesized and studied by thermogravimetric analysis. The thermal dehydration and decomposition of these complexes were studied kinetically using the integral method applying the Coats-Redfern equation. It was found that the thermaldecomposition of the complexes follow second order kinetics. The thermodynamic parameters of the decomposition are also reported. The electronic absorption spectra of the
Synthesis, spectroscopic characterization, thermal studies, catalytic epoxidation and biological activity of chromium and molybdenum hexacarbonyl bound to a novel N2O2 Schiff base
作者:Ayman A. Abdel Aziz
DOI:10.1016/j.molstruc.2010.06.004
日期:2010.8
behaviors of the complexes were also studied by using thermogravimetric analysis (TGA). The catalyticactivity of the novel complexes in the epoxidation of cyclooctene, cyclohexene, 1-octene and 1-hexene with tert -butyl-hydroperoxide (TBHP) in methylene chloride was investigated. The antimicrobial activities of the ligand and their complexes have been screened against various strains of bacteria and