Produces tracing

Distillation of tetrachloroethylene (formerly a dry-cleaning solvent) in new galvanised steel equipment produces traces of dichloroacetylene. This is toxic and may cause ill-health in those exposed. Should the acetylene chance to be concentrated (as in the sub-entry above), it is also very explosive. The galvanised metal becomes passivated in a few days and the effect was not found with other steels. 

Anhydrous lanthanum fluoride also may be made by passing dry hydrogen fluoride over lanthanum oxide. This process, however, produces trace amounts of lanthanum oxyfluoride, LaOF. Highly purified material may be obtained by passing dry purified HF over molten fluoride in a platinum crucible. 

The reaction between SnCl2 and methylcobalamin in 1.0 M HC1 is first order in each reactant, with a rate constant of 1.04 0.10M sec-1 (256). The reaction is hypothesized as passing through a methyltin(III) radical intermediate. Ethylcobalamin and chloromethylcobalamin also react with SnCl2, with rate constants of (1.66 0.20) x 10 3M 1 sec-1 and 7 x 10 3 sec-1, respectively (256). Reaction between CdCl2 and methylcobalamin at pH 9.6 produced traces of an unidentified volatile Cd compound (257). 

P.A. Pella, Generator for Producing Trace Vapor Concentrations of TNT, 2,4-DNT and EGDN for Calibrating Explosive Vapor Detectors , AnalChem 48, 1632-37 (1976)... 

Fatty acids are the building blocks of TAG. More than 90 percent of fatty acids have an even number of carbon atoms, and are in aliphatic chains ranging from 4 to 22 carbons in length. The major fatty acid synthesis pathway is production of stearic acid (18 carbons) after which separate desaturase systems introduce 1, 2, or 3 unsaturated (double) bonds. Additional enzymes become active in elongating the chain as needed. Shorter fatty acids also are produced. Trace amounts of odd-number carbon fatty acids are found in most fats, and also have been synthesized for research purposes. Microorganisms frequently produce odd-number carbon fatty acids, with heptadecenoic (17 carbon) acid a major component of Candida tropicalis yeast fat. Up to 8 percent C17 fatty acids have been found in milk and meat fats of ruminants (cattle, sheep, goats) and are of rumen microbe origin. 

Pella, P. A. (1976). Generator for producing trace vapor concentrations of 2,4,6-trinitrotoluene,2,4-dinitrotoluene, and ethylene glycol dinitrate for calibrating explosives vapor detectors. Ana/. Chem., 48, 1634-7. [291]... 

Sometimes, the role of the coupling partner is important for the success of a coupling reaction. Imidazole stannane 367 reacted with iodoimidazolopyridine 366 under the common Stille conditions to give product 368 in good yields. However, under the same conditions, iodoimidazole 370 and stannane 369 only produced traces of the desired product 368 (Scheme 87) <2003HCA3461>. 

Figure 2(C) is the result of a calculation that illustrates which cations might fit into sixfold coordination position in the calcite group structures. It is an interesting insight as both light and heavy rare earth elements are possible substitutes for calcium in the calcium carbonate structure, i.e., they plot within 15% of the calcium ionic size. However, some of the end-members incorporate elements into this crystal structure and are outside this deviation but within 30%, an expression of the potential physical expansion for this layered crystal structure. These are ionic charge differences important in whether a stable crystalline structure can be produced. Trace amounts of all these ions can be incorporated in calcite and may dictate the morphology of the crystallites. Therefore, the presence and amount of any ions in the environment in which carbonate crystallization occurs may possibly be recorded. However, in spite of the predominance of sodium and potassium in the solutions where...

This method is similar to the Soda-Ash process. The difference consisted of g a solution of sodium sulphite (16 -17% Na SOj) added with ammonia gas bubbling it to 2% free NHj. The solution should have pH 5. The pH value to 8.5 after mixing the solution with TNT (15 min). The solution contains onium nitrate, sulphate and sulphite. Free sodium sulphite causes the form-n of a red colour in the slurry of TNT with the aqueous solution. TNT made this method is slightly darker owing to the action of ammonia on 0- and itrotoluene producing traces of 2.4- and 4.6 dinitro-3-toluidine. Traces of... 

The aromatic acids released from different HA upon pyrolysis in the presence of TMAH probably represent original components of the HA structure released by the thermolytic action of TMAH (10,12,16,17). This observation is supported by the TMAH thermochemolysis data of Hatcher et al. (23) and Hatcher and Clifford (16) for a volcanic soil humic acid. In fact, the C-NMR spectrum of this particular HA (shown in Figure 4) clearly indicates that it is composed of only aromatic and carboxyl carbons. Conventional pyrolysis of these HA produced trace quantities of volatile products without the release of any significant compounds while pyrolysis in the presence of TMAH yielded mainly benzenecarboxylic acid methyl esters (Figure 5), in accordance with the NMR data. 

There is a very early report that phosgene reacts with hydrogen bromide above 200 C to produce trace amounts of COBr, [184a]. Hydrogen iodide reacts with phosgene vigorously to liberate iodine and carbon monoxide [184a]. 

A preliminary report on microbial reaction with Cd indicated a strain of Pseudomonas produced trace amounts of a volatile Cd species from inorganic Cd(II) in the presence of vitamin B12, but provided no evidence for biomethylation of Cd °. The prospect of Cd methylation has been considered by others". 

In the 1970s, formulations of 2,4,5-T typically contained 10-100 ppm of TCDD. The concentration of TCDD in the product can be limited to about 0.1 ppm by careful temperature control of the exothermal reaction. However, the manufacture of the herbicide seems inevitably to produce traces of TCDD, and the registration of 2,4,5-T was ultimately withdrawn in North America due to public pressure. At present, this formulation is still manufactured in some Asian countries. 

Xanthine oxidase (EC 1.2.3.2) catalyzes the formation of uric acid, an end-product of purine catabolism. The mammalian enzyme is a metalloflavoprotein composed of two subunits containing molybdenum, FAD and Fe/S clusters as prosthetic groups in a ratio of 1 1 4 per subunit (1). Besides its endogenous metabolic function, xanthine oxidase is also active toward a wide spectrum of oxidizable xenobiotic substrates. Although some cestodes and trematodes produce trace amounts of uric acid (16), the presence of xanthine oxidase activity in these organisms has not been demonstrated. Xanthine oxidase was found in the cytosolic fractions of the nematodes Ancylostoma ceylanicum and Nippostrongylus brasiliensis (17), but its activity toward xenobiotic substrates was not tested. 

Chlorinating drinking water kills microbes but produces trace amounts of a group of potentially harmful substances called trihalomethanes (THMs), the most prevalent of which is chloroform. Federal regulations have been proposed to limit THM levels in drinking water to 40 Xg/L (Davis and Cornwell, 1998). Sparging with ambient air in a bubble column is an effective method to strip the water of THMs. 

CHEMICAL PROPERTIES stable heating above 200°C produces traces of octachlo-rodibenzo-para-dioxin corrosive in presence of moisture reacts with acid chlorides, acid anhydrides, strong oxidizers, and strong bases FP (none) LFL/UFL (none) AT(none) HC (not available). 

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