Hydrocarbons infrared analysis

Reference methods for criteria (19) and hazardous (20) poUutants estabHshed by the US EPA include sulfur dioxide [7446-09-5] by the West-Gaeke method carbon monoxide [630-08-0] by nondispersive infrared analysis ozone [10028-15-6] and nitrogen dioxide [10102-44-0] by chemiluminescence (qv) and hydrocarbons by gas chromatography coupled with flame-ionization detection. Gas chromatography coupled with a suitable detector can also be used to measure ambient concentrations of vinyl chloride monomer [75-01-4], halogenated hydrocarbons and aromatics, and polyacrylonitrile [25014-41-9] (21-22) (see Chromatography Trace and residue analysis). 

An alternative method for fractionating and purifying petroleum hydrocarbons prior to GC or HPLC separation has been developed (Theobald 1988). The method uses small, prepacked, silica or Cjg columns that offer the advantage of rapid separation (approximately 15 minutes for a run) good recovery of hydrocarbons (85% for the Cjg column and 92% for the silica column) reusability of the columns and for the silica column in particular, good separation of hydrocarbon from non-hydrocarbon matrices as may occur with environmental samples. Infrared analysis and ultraviolet spectroscopy were used to analyze the aromatic content in diesel fuels these methods are relatively inexpensive and faster than other available methods, such as mass spectrometry, supercritical fluid chromotography, and nuclear magnetic resonance (Bailey and Kohl 1991). 

Air oxidation of coal causes a significant decrease in the concentration of aliphatic bridges as determined by acid-catalyzed transalkylation of coal with phenol. Infrared analysis of the raw and oxidized coals indicate that the hydrocarbon bridges are converted to carbonyl groups. Plausible explanations have been offered for the formation of carbonyl groups from aliphatic bridges. 

An Infrared Analysis Method for the Determination of Hydrocarbons Collected on Charcoal Tubes... 

We believe it has been shown that this method for infrared analysis of hydrocarbons collected on charcoal tubes and vapor monitors is a valid and acceptable one. Further work is being done to validate the method for other hydrocarbons such as petroleum naphtha, Stoddard solvent, and other JP aviation fuels. Additionally, work is being done to determine the 3M monitor sampling rate for JP-4. 

The results of the infrared analysis are presented in Table VI. These results show that carboxylic acids and phenols are found only in the acid concentrates. Carboxylic acids are concentrated in the polar acid subfractions III and IV while phenols are concentrated in subfraction II. Carbazoles, ketones, and amides are found in all three major nonhydrocarbon fractions. The appearance of the same compound type in several fractions may arise from differences in acidity or basicity that are caused by the hydrocarbon portion of the molecule. Multifunctionality could also be a factor in the distribution of compound types among the fractions. The 1695 cm"1 band was assigned to ketones on the basis of work... 

The concentrations of hydrocarbon at the inlet and outlet of the reactor were measured using FTIR (Nicolet) with a meicury-calcium-telluride (MCT) detector, which was cooled by liquid nitrogen and gas cell (Infrared Analysis), and with 16 scans and a resolution of 2 cm. The concentrations were also checked using GC (HP3890plus) with FID (flame ionization detector) and HP plot column. The vapor pressures of the hydrocarbons were calculated by using Reid equation [6]. 

The reaction was studied by Daignault and Walters in the temperature range 360-410 °C. By infrared analysis ethylene and methyl vinyl ketone were shown to be formed in equal amounts. Mass-spectrometric analysis of the gas fraction revealed the presence of 99.4% C2H4, 0.1 % CjHe, 0.1 % C3H6, 0.03% CjHg and higher paraffins, 0.2 % butenes and 0.2 % of other C4 hydrocarbons. The stoichiometry of the decomposition can be given, almost quantitatively, by... 

Carbon monoxide may be determined over a wide range of concentration via infrared analysis [25]. Good results are achieved at concentrations as low as 1.25 to 2.5 mg m . The main disadvantage of this technique is the non-linear response, as well as possible interference by CO2, water vapour and hydrocarbons. The use of the gas chromatography for determining CO includes a catalytic reduction system, which converts carbon monoxide quantitatively to methane and a flame ionization detector. For a rapid CO determination, indicator tubes with palladium salt as a catalyst and silicomolybdate complex, which yields a blue colour with carbon monoxide, are used. The CO determination can also be carried out on the basis of its reaction with the radioactive kryptonate of palladium chloride [18, 25]. 

The butyl polymer (E) gave a nonlinear curve indicating that possibly two or more products were being condensed. Only one product, stearic acid, was identified by infrared analysis, however, it is possible that other oxidized hydrocarbons were present in lesser concentrations. Stearic acid is used in many rubber formulations as an accelerator activator and as a lubricant processing aid ( 7), and usually exists in the free state in the rubber. It is therefore easily outgassed, as are the plasticizers, and condenses on the cooler surfaces of the collector. The stearic acid was still being evolved after 225 hours at 150°C. 

Infrared analysis can be applied to extractions of body fluids for the following classes of compounds (a) halogenated hydrocarbons (b) alcohols (c) ethers and aldehydes and (d) ketones. Most of the 160 substances (except the gases) given in the table of Stewart and Erley (1965) referred to earlier may be extracted from body fluids and analyzed by infrared methods. 

Calculated from G values of isolated hydrocarbons assuming scission efficiency of 0.073 X 10 per 1000 carbon atoms. Because short-chain branches outnumber chain ends by 30 1, no correction for the fragmentation products at chain ends was made. + Determined by infrared analysis. Determined by radiolysis. Reproduced with permission from P.M. Kamath and A. haclow. Journal of Polymer Science-. Polymer Chemistry Edition, 1967, 5, 2023. 1967, Wiley ... 

J. H. Lee, Determination of Extinction Corrections in Infrared Analysis of Gaseous Hydrocarbon Mixtures, Anal, Chem. 18, 659, 1946. 

One has seen that the number of individual components in a hydrocarbon cut increases rapidly with its boiling point. It is thereby out of the question to resolve such a cut to its individual components instead of the analysis by family given by mass spectrometry, one may prefer a distribution by type of carbon. This can be done by infrared absorption spectrometry which also has other applications in the petroleum industry. Another distribution is possible which describes a cut in tei ns of a set of structural patterns using nuclear magnetic resonance of hydrogen (or carbon) this can thus describe the average molecule in the fraction under study. 

Principal component analysis has been used in combination with spectroscopy in other types of multicomponent analyses. For example, compatible and incompatible blends of polyphenzlene oxides and polystyrene were distinguished using Fourier-transform-infrared spectra (59). Raman spectra of sulfuric acid/water mixtures were used in conjunction with principal component analysis to identify different ions, compositions, and hydrates (60). The identity and number of species present in binary and tertiary mixtures of polycycHc aromatic hydrocarbons were deterrnined using fluorescence spectra (61). 

Methods utilizing characteristic physical properties have been developed for several chlorinated hydrocarbon insecticides. Daasch (18) has used infrared spectroscopy for the analysis of benzene hexachloride. By this means it is possible to determine the gamma-isomer content, as well as that of the other isomers of technical benzene hexachloride, provided the product is substantially free of the higher chlorinated cyclohexanes. 

Naphthalene-2,3-dicarboxaldehyde Nicotinamide adenine dinucleotide N-Acetylneuraminic acid 4-Fluoro-7-nitrobenzoxadiazole Naphthalene-2,3-dicarboxaldehyde Nondestructive readout Near infrared Near infrared fluorescence Nuclear magnetic resonance 2-Nitrophenyl oxalate 1,1 -Oxalyldiimidazole Polycyclic aromatic hydrocarbon Principal component analysis Photosensitized chemiluminescence Pentachlorophenyl oxalate Polymerase chain reaction... 

Detectors with complete black body rejection capability are usually less sensitive to fires than a single frequency infrared optical detector. Because it s discrimination of fire and non-fire sources depend upon an analysis of the ratio between fire and reference frequencies, there is a variation in the amount of black body rejection achieved. A detector s degree of black body radiation rejection is in inversely proportion to its ability to sense a fire. The detectors are limited to applications that involve hydrocarbon materials. 

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