Determination aniline point

Other terms relating to physical properties include viscosity refractive index pour point, ie, the lowest temperature at which the oil flows flash point, ie, the temperature at which the oil ignites and aniline point, ie, the minimum temperature at which equal volumes of oil and aniline are completely miscible. These are determined under defined conditions estabHshed by ASTM. 

Solubility of resins can be predicted in a similar way as for the solubility of polychloroprene rubbers in a solvent mixture (see Section 5.5) by means of solubility diagrams (plots of the hydrogen bonding index (y) against the solubility parameter (5). Another more simple way to determine the solubility of resins is the determination of the cloud point, the aniline and the mixed aniline points. 

Aniline is an aromatic amine (CgHjNHj). When used as a solvent, it is selective to aromatic molecules at low temperatures, and paraffins and naphthenes at higher temperature. Aniline is used to determine aromaticity of oil products, including FCC feedstocks. Aniline point (AP) is the minimum temperature for complete solubility of an oii sample in aniline. 

Plot the feed refractive index, API gravity, and aniline point. Determine any shift in the amount of cracked gas oil in the feed. 

Aniline Point is the minimum temperature for complete miscibility of equal volumes of aniline and the hydrocarbon sample. In cat cracking, aniline solution is used to determine aromaticity of FCC feedstocks. Aromaticity increases with reducing aniline point. 

Of the petroleum solvents, the aromatic fractions are much better solvents for DDT than the paraffinic fraction. The limited solubility of DDT in the paraffinic fraction, representative of straight-run petroleum oils, shows that such oils alone cannot be used as solvents in concentrated DDT solutions. An auxiliary solvent would have to be used to prepare concentrated solutions with them. It was not possible to correlate solubility with mixed aniline point and aromatic content. This was presumably due to differences in the solubility of DDT in the individual hydrocarbons present which included both monocyclic and dicyclic types. No attempt was made to determine the amount of the individual hydrocarbons in the aromatic fractions. 

Thus it is possible to determine the value of the aniline point (A.P.) of a saturated mineral oil fraction by means of Fig. 9 if the specific refraction and the molecular weight are known. 

The aniline point of crude oil is the temperature at which equal parts of aniline and the oil are completely miscible. For oils of a given type, the aniline point increases slightly with molecular weight but increases markedly with paraffinic character and may therefore be used to obtain an approximate estimation of aromatics content. Aniline point determinations are only infrequently applied to heavy oils and residua since their very character, and the other evaluation methods outlined here, indicates them to be complex with high proportions of ring systems (aromatic constituents and naphthene constituents). 

In the same experiments the degree of hydrogenation of the middle oil has been determined. Figure 14 is a graph of the aniline point of the prehydrogenation middle oil (180° to 325°C.) for the four catalysts at varying temperatures. The aniline point increases with reaction temperature... 

Aniline is employed in an important routine test used in the petroleum industry for the determination of the approximate aromatic content of oils. The aniline point is the lowest... 

The distillation tests give an indication of the types of products and the quality of the products that can be obtained from petroleum, and the tests are used to compare different petroleum types through the yield and quality of the 300°C (572°F) residuum fraction. For example, the waxiness or viscosity of this fraction gives an indication of the amount, types, and quality of the residual fuel that can be obtained from the petroleum. In this respect, the determination of the aniline point (ASTM D-6II, IP 2) can be used to determine the aromatic or aliphatic character of petroleum. Although not necessarily the same as the wax content, correlative relationships can be derived from the data. 

The test method for the determination of aniline point and mixed aniline point of hydrocarbon solvents (ASTM D-611, IP 2) is a means for determining the solvent power of naphtha by estimating of the relative amounts of the various hydrocarbon constituents. It is a more precise technique than the method for kauri-butanol number (ASTM D-1133). 

There are five submethods in the test (ASTM D-611, IP 2) for the determination of the aniline point (1) Method A is used for transparent samples with an initial boiling point above room temperature and where the aniline point is below the bubble point and above the solidification point of the aniline-sample mixture (2) method B, a thin-film method, is suitable for samples too dark for testing by method A (3) methods C and D are used when there is the potential for sample vaporization at the aniline point (4) method D is particularly suitable where only small quantities of sample are available and (5) method E uses an automatic apparatus suitable for the range covered by methods A and B. 

An indication of naphtha composition may also be obtained from the determination of aniline point (ASTM D-1012, IP 2), freezing point (ASTM D-852, ASTM D-1015, ASTM D-1493) (Fig. 4.2), cloud point (ASTM D-2500) (Fig. 4.3), and solidification point (ASTM D-1493). And, although refinery treatment should ensure no alkalinity and acidity (ASTM D-847, ASTM D-1093, ASTM D-1613, ASTM D-2896, IP 1) and no olefins present, the relevant tests using bromine number (ASTM D-875, ASTM D-1159, IP 130), bromine index (ASTM D-2710), and flame ionization absorption (ASTM D-1319, IP 156) are necessary to ensure low levels (at the maximum) of hydrogen sulfide (ASTM D-853) as well as the sulfur compounds in general (ASTM D-130, ASTM D-849, ASTM D-1266, ASTM D-2324, ASTM D-3120, ASTM D-4045, ASTM D-6212, IP 107, IP 154) and especially corrosive sulfur compounds such as are determined by the Doctor test method (ASTM D-4952, IP 30). 

An alternative criterion of energy content is the aniline gravity product (AGP), which is fairly accurately related to calorific value but more easily determined. It is the product of the gravity at 60°F (expressed in degrees API) and the aniline point of the gasoline in °F (ASTM D-611, IP 2). The aniline point is the lowest temperature at which the gasoline is miscible with an equal volume of aniline and is inversely proportional to the aromatic content and related to the calorific value (ASTM D-1405, IP 193). 

The aniline gravity product is not always suitable for determining the heat of combustion because of the difficulties that can be encountered in determining the aniline point of the fuel (ASTM D-611, IP 2). It is... 

Several tests that are usually applied to the lower-molecular-weight colorless (or light-colored) products are not applied to residual fuel oil. For example, test methods such as those designed for the determination of the aniline point (or mixed aniline point) (ASTM D-611, IP 2) and the cloud point (ASTM D-2500, ASTM D-5771, ASTM D-5772, ASTM D-5773) can suffer from visibility effects because of the color of the fuel oil. 

The standard tests used to determine the properties of petroleum and petroleum products are commonly applied to grease. Among these are aniline point (ASTM D-611), carbon residue (ASTM D-189,ASTM D-524, ASTM D-4530, IP 13, IP 14, IP 398), fire point (ASTM D-92), flash point (ASTM D-92), pour point (ASTM D-97), and viscosity (ASTM D-445). However, because of the complexity of grease formulations and the variety of uses, many other tests are also deemed necessary to estimate performance in service. Other tests not included in this chapter may be found elsewhere under the test methods for lubricating oil (Chapter 12). Some modification of the test method may be necessary because of the different character of grease vis-a-vis lubricating oU. 

Aniline point This is a measure of the ability of the base stock to act as a solvent and is determined from the temperature at which equal volumes of aniline and the base stock are soluble (ASTM D611). High aniline points (approximately 100°C or greater) imply a paraffinic base stock, while low aniline points (less than 100°C) imply a naphthenic or aromatic stock. 

The aniline point determination is another method of establishing the solubilizing power of a solvent by simple means. Here, the temperature is measured at which a solution just becomes eloudy. Figure 2.3.21 shows that there is a good correlation between the Kauri number and the aniline point. Also dilution ratio of cellulose solution is measured by standardized methods (see Chapter 15). 

Solvent strength Solvent strength is used to establish required solvent concentration to form a clear solution and to estimate the diluting capabilities of pre-designed system. T wo determined quantities are used for the purpose Kauri butanol value and aniline point. 

The aromatic content of hydrocarbon mixture is estimated from the determination of aniline point.Aromatic hydrocarbons have the lowest and paraffins the highest aniline points. Cycloparaffins and olefins are between the two. Aniline point increases as the molecular weight increases. A mixture of specific aniline and solvent is heated at a controlled rate until it forms one phase. The mixture is then cooled and the temperature at which the miscible liquid separates into two phases is determined. Four methods are discussed in the standard suitable for transparent, non-transparent, easily vaporizing, and measured in small quantities. 

ISO 2977-97. Petroleum products and hydrocarbon solvents - Determination of aniline point and mixed aniline point. 

The aniline point (ASTM D 611) is the lower equilibrium solution temperature for equal volumes of aniline and solvent. w-Heptane is the standard hydrocarbon solvent with an aniline point of 69.3 "C. The aniline point decreases from approx. 90°C for isoparaffins to 10°C for solvents with a medium aromatic content. Highly aromatic solvents result in values below 0°C so that the aniline can crystallise from the mixture. Mixed aniline points (ASTM D 1012) are used in these cases. This is the minimum equilibrium solution temperature of a mixture of two volumes of aniline, one volume of solvent and one volume of w-heptane. The relationship between the KB-number and aniline point for zero to medium aromatic content hydrocarbon solvents is shown in Figure 2.1. Figure 2.2 demonstrates the relationship between aniline and mixed aniline points. Toluene/ i-heptane blends have been used for its determination. The relationship between KB-number and mixed aniline points for solvents with a medium to high aromatic contents is given in Figure 2.3. 

The higher the aromaticity of the oil the lower the aniline point. The aniline point can be influenced by the molecular weight of the oil and can be difficult to determine when using very dark and opaque oils. 

This point is defined as the lowest temperature at which aniline is soluble in a specified amount of sample. This measure is used to determine the solvency of the hydrocarbons Typically paraffinic hydrocarbons have higher aniline points than aromatic hydrocarbons. This method is usually performed under the guidelines of ASTM D 611. Aniline point can be used to determine the quality of ignition in diesel euts. 

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