Nitrogen elemental analysis

This mechanism could be demonstrated via nitrogen elemental analysis of polymers and copolymers treated with amine acid salts and thermally cured (Table II and Experimental). In a control experiment, ammonium acetate was added In excess to a vinyl acetate/ethylene emulsion copolymer without amlnoplast crosslinker to confirm that essentially all of the ammonia volatilized from the unfunctlonallzed polymer during cure (much poorer volatilization was observed If NH4CI was used In place of NH4OAC). 

Anchoring polymers are prepared from chloromethylated styrene-divinylbenzene copolymers of either 1 equiv Cl/g or 4 equiv Cl/g capacity. These resins arc stirred for 24 h in refluxing CHC13, with either 1,4-diazabicyclo[2.2.2]octane, hexamethylenetetramine, or TMEDA. The polymers are filtered off, washed with ClIClj, acetone and Et20, then dried overnight under vacuum at 25 °C. Nitrogen elemental analysis and chloride ion titration gives a value of 80-90% quaternarization. 

Ethylene dimethacrylate (5.64 g), methacrylic acid (0.52 g 6.0 mmol), L-phenylalanine anilide (0.25 g 1.5 mmol), and of AIBN (W mg) in acetonitrile 98.2 mL) were mixed in a glass tube. After degassing, the tube was sealed under nitrogen and consecutively heated for 24 h each at 60, 90, and 120 °C. Subsequently, the polymer was ground and subjected to continuous extraction in acetonitrile for 24 h. To determine the recovery of imprint molecules, the extracted anilide was quantitatively determined and the polymer was investigated by nitrogen elemental analysis before and after extraction of the imprint molecule. According to these methods about 90% of the imprint molecules had been removed from the polymers. 

Carbon, hydrogen, and nitrogen elemental analysis results for the aminated silanes-molybdenum oxide hybrids samples are summarized in Table 6.4. The BET surface area results are summarized in Table 6.5. 

The composition of the isolated copolymer was determined from (a) the nitrogen elemental analysis, and (b) the sulfur elemental analysis. Both figures were corrected for the small amount (4-12%) of water associated with the polymer. 

Carbon, hydrogen, nitrogen elemental analysis (Vogel, 1989)... 

Table 1. Carbon, Hydrogen and Nitrogen elemental analysis of bis-l,n-(p-carboxyphenoxy)alkane aromatic acids...

Faraday also heated the rubber in an anaerobic distillation apparatus, as described in Murray s account. A group of volatile substances were isolated. He was able to show that caoutchouc is a pure hydrocarbon, with no traces of oxygen or nitrogen. Elemental analysis yielded a C/H ratio of 8/7 in early nineteenth century practice. (Carbon was then treated as M = 6, rather than 12, with H as 1). Modem values are represented by the empirical formula CsHg. 

Interest in the mechanism and product distribution of thermal and photochemical transformations of aryl azides led to the isolation of some nitrogen-containing derivatives of heptafulvalene. Based on elemental analysis and spectroscopic data it has been suggested tentatively that the compound isolated following vapor-phase pyrolysis of azidopentafluoro-... 

An elemental analysis of epinephrine resulted in the following composition 59.0% carbon, 26.2% oxygen, 7.15% hydrogen, and 7.65% nitrogen by mass. When 0.64 g of epinephrine was dissolved in 36.0 g of benzene, the freezing point decreased by 0.50°C. (a) Determine the empirical formula of epinephrine, (b) What is the molar mass of epinephrine ... 

The thermal cracking of a light ffaction of mixed plastics waste was carried out in a fluidised bed reactor and the fractions obtained were analysed by elemental analysis, gas chromatography and ashing. The main components of the waste were PE and PP with a small amount of PS and the bed was fluidised by pyrolysis gas, nitrogen or preheated steam. Experiments conducted at different temperatures and residence times were compared by calculating the crack severity for each experiment. The results obtained revealed that the amounts of ethene and propene obtained by pyrolysis with steam were comparable with those obtained using a commercial steam cracker. 

Comparative studies of the widely employed spectrophotometric readings at the Soret and Q bands (405 and 630 nm, respectively) and the elemental analysis of copper and nitrogen showed that the spectrophotometric assay based only on the Soret band can overestimate the purity of a preparation. Erroneous data were attributed to an increase in absorptivity at the Soret band when other colored compounds like metal-free analogs and carotenoids are present. Indeed, copper-free chlorin e6 exhibits a specific absorbance 3.6 times greater than that of its coppered counterpart. Therefore, measurements at the Q band (630 mn) and the establishment of the S Q ratio are preferred. 

If the sample is pure (this can generally be checked by thin layer chromatography or gas chromatography) then the elemental analysis values for carbon, hydrogen and nitrogen can be used to obtain element ratios, provided that C, H, N and 0 are the only elements present. 

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