Refractive index petroleum products

The refractive index (n) of a feed sample is proportional to its aromatic content the higher the value the more aromatic compounds are present in the feed. There are many methods to predict composition of petroleum products based on refractive index measurements [11]. The best linear regression model to predict refractive index (n) based on H-NMR spectra has the form ... 

Thorium oxide has a high refractive index and low dispersion and thus finds use in high-quality camera and scientific instrument lenses. Thonum oxide also is used as a catalyst in the conversion of ammonia to nitnc acid, in petroleum cracking, and in sulfuric acid production. 

Preparation of 2-Allylphenol. The allyl ether is boiled in a flask under a reflux tube, the course of the rearrangement being conveniently followed by noting the refractive index at frequent intervals. When nu has risen to 1.55 (five to six hours) the rearrangement is substantially complete with the minimum formation of undesirable by-products. To separate a small amount of 2-methyldihydrobenzofuran, the product is dissolved in tivice its volume of 20% sodium hydroxide solution and extracted twice with petroleum ether (30-60°), from which the dihydro-benzofuran residue may be obtained by distillation. Ether should not be used for this extraction as it removes some of the phenol from the alkaline solution. The alkaline solution is acidified and the phenpl extracted with ether the extract is dried over calcium chloride and distilled under diminished pressure. A 73% yield of material boiling at 103-105.5°/19 mm., no 1.5445, is obtained. 2-Allylphenol is a colorless liquid, of guaiacol-like odor, with the following properties b.p. 220°/ 760 mm., 99°/12 mm., nf) 1.5453. ... 

Correlative methods have long been used as a way of dealing with the complexity of petroleum fractions. Relatively easy to measure physical properties such as density, viscosity, and refractive index (ASTM D-1218) have been correlated to hydrocarbon structure (Table 7.3) with the potential to relate refractive index data to the nature of the constituents of a petroleum product. 

Test methods of interest for hydrocarbon analysis of residual fuel oil include tests that measure physical properties such as elemental analysis, density, refractive index, molecular weight, and boiling range. There may also be some emphasis on methods that are used to measure chemical composition and structural analysis, but these methods may not be as definitive as they are for other petroleum products. 

The evaporative light-scattering detector (ELSD) is a near universal detector suitable for the determination of (mainly) neutral compounds that are less volatile than the mobile phase used for the separation [151,152]. Primary uses include the detection of compounds with a weak response to the UV detector, especially carbohydrates, lipids, surfactants, polymers and petroleum products. Its greater sensitivity and ease of use in gradient elution separations makes it preferable to the refractive index detector for these applications. The ELSD is compatible with most volatile solvents used for normal and... 

ISO 5661-83. Petroleum products - Hydrocarbon hquids - Determination of refractive index. 

Ratio of the velocity of light at a specified wave length in air to its velocity in a substance under examination. The refractive index can be determined by test method ASTM D642, using a refractometer and a monochromatic light source. Refractive index is an excellent test for uniform composition of solvents, rubber process oils, and other petroleum products. It may also be used in combination with other simple tests to estimate the distribution of naphthenic, paraffinic, and... 

Turpentine Oil. Petroleum products are frequently used for the adulteration of turpentine and are to be suspected if a low weight per ml and refractive index are found. The original method of polymerisation and sulphonation proposed by x rmstrong for the direct determination and separation of petroleum spirit has been recommended by Coste for confirmation of these suspicions, and in his opinion was in every way preferable to the various drastic processes suggested by other workers. As small a quantity as 100 ml of turpentine should, with care, give reliable results by this method. 

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