Oven temperature oxidation

Ee was determined by gas chromatography (GC) on a Supelco Beta-DEX 120 column (fused-sihca capillary column, 30 m, 0.25 mm inner diameter, 0.25 mm film thickness Supelco, Buchs, Switzerland) with spht injection (20 1) and an isothermal oven temperature profile at 90 °C for separation of styrene oxide enantiomers. 

Activity Measurements. To test catalytic properties of various samples partial oxidation of methanol to formaldehyde was studied in a flow micro-reactor operating under normal atmospheric pressure (10). For each run about 0.2 g of catalyst sample was used and the activities were measured at 173 C in the absence of any diffusional effects. The feed gas consisted of 72, 2 and by volume of nitrogen, oxygen and methanol vapor respectively. Reaction products were analysed with a 10% Carbowax 20 M column (2m long) maintained at 60 C oven temperature. 

Chemical Analysis. Gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) techniques were used to analyze 4-chlorophenol and its oxidation intermediates. For GC-MS analysis, the samples were acetylated in pyridine. The samples were first evaporated to dryness. Then 200 xL of pyridine and 200 (xL of acetic anhydride were added to the dry residue. The samples were heated at 65 °C for 2-3 h to ensure the complete acetylation reaction, and then gently evaporated to dryness in a nitrogen stream. Finally, the residue was redissolved in 0.1 mL of hexane for GC analysis. A GC (HP model 5890) equipped with mass selective detector (HP model 5971) and SPB-5 capillary column (Supelco Co., PA., 25- X 0.2-mm i.d. X 0.33-p.m film thickness) was used. To separate different intermediate products, various oven-temperature programs were performed. The GC-MS interface line was maintained at 300 °C. The mass-... 

Activation by reduction of the Rh-containing cubic m lxed oxides changes the order of activity, since the performances of all the Rh/Mg/Al catalysts improved considerably in terms of both activity and stability (Fig. 3). The complete decomposition of N2O (residual amount lower than 50ppm) is reached using an oven temperature of 350-400°C, as a... 

Vapour-phase oxidation of IBA was carried out in a continuous-flow laboratoiy reactor, at atmospheric pressure. The standard feed composition was IBA 2%, O2 20%, H2O 4%. liie toted flow rate was 60 mL/min and the amount of catalyst used was 1 g (approximately 1 mL). The reaction products, kept at 200C to prevent condensation, were analysed by gas chromatography a GP 10% SP-1200/1% H3PO4 on Chromosorb WAW was used to separate IBA, propylene, acetone and MAA, with oven temperature programmed om 40 to lOOC (FID) a Carbosieve S column was utilized for analysis of CO and CO2, with oven temperature programmed from 40C to 200C (TCD). All the catalysts were kept under reaction environment for approximately 50-70 hours along this period, after an initial unstable behavior, no deactivation phenomena were observed. 

Lipid Composition. After the behavior experiments, the rats were killed by decapitation. Tissue samples including brain and retina were removed and stored at -80°C. The total lipid extracts of tissues were prepared according to the method of Folch et al. (39). Butylated hydroxytoluene (300 qg/sample) was added in methanol to each sample to minimize lipid oxidation. The total lipid extracts were trans-methylated with 14% BFj/methanol at 100°C for 60 min by a modification (40) of the method of Morrison and Smith (41). Fatty acid methyl esters were then analyzed on a Hewlett-Packard 5890 gas chromatograph (Hewlett-Packard, Palo Alto, CA) equipped with a flame ionization detector and fused silica capillary column (DB-FFAP, 30 m X 0.25 mm x 0.25 m, J W, Folsom, CA) with carrier gas (hydrogen) at a linear velocity of 50 cm/s. Injector and detector temperature were set to 250°C and oven temperature program was as follows 130 to 175°C at4°C/min, 175 to 210°C at l°C/min, and then to 245 at 30°C/min, with a final... 

Fig. 4-154 DSC Oxidation of Polysiloxanes after Oven Aging 120 Days Low Temperature Oxidation (LTO Peak 1)...

Dunham and Edie (1992) [219] used bundles of 12,000-60,000 filaments to establish a model of stabilization for Courtauld s SAP PAN based precursor by grouping the many reactions into three major groups of reactions—cyclization, dehydrogenation and oxidation. They found that bundle temperatures could be as much as 15°C above the oven temperature and predicted that incremental oven temperature profiles should be useful in reducing the time taken for stabilization. 

Instead of using ovens to oxidize the fiber, a totally different approach would be to pass the fiber around a series of uniformly heated rollers. Figure 10.7 shows a proprietary induction heated roller with a jacket containing a liquid/vapor thermal transfer medium, which will maintain a uniform temperature of 2°C at 230°C along the length of the roller (Figure 10.8). 

Fused-silica aluminum oxide ALOT column 30 m x 0.32 mm oven temperature 60 °C detector FID split ratio, split injection 1 25 of 20 nl gas mixture of Ci - 64 hydrocarbons water equalizer. 

It should also be noted that at elevated temperatures ethanol can become oxidized to acetaldehyde, so the gas chromatographic procedure must separate ethanol from acetaldehyde. The author s laboratory historically used a 6-ft glass column (2 mm i.d.) packed with 5% Carbowax 20 M on Carbotrap B 60/80 mesh to perform blood alcohol analyses. When the oven temperature is held at... 

Oxygen degrades the stationary phases. For column storage it is recommended to seal the ends with a septum, and store in a dark place, typically the column box, to prevent stationary phase damage by oxidation, moisture and UV light. Not used installed GC columns should get a low carrier gas flow with spUt open at low flow as well (prepare a standby method at low oven temperature). Ah column manufacturers provide upper and lower temperature hmits for use of the individual columns and stationary phases ... 

In one series of experiments [45] a quasi-one-dimensional catalyst in the form of a Ni ring was used (3.8 cm outer and 3.2 cm inner diameter, 0.13 mm thickness). The catalyst was activated by repeated oxidation-reduction cycles at about 720 K [51]. For feed and oven temperatures around 500 K, a pulse rotating around the Ni ring in about 10 min was observed [45]. The integrated behavior (oxygen conversion in the reactor) exhibited periodic oscillations with 3 maxima and minima per rotation period. This clearly showed that the... 

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