Aniline point

Since like dissolve like, aniline is readily soluble in those lubricants which are rich 

Aniline Point (also known as Standard Aniline Point), with respect to petroleum oils, is the lowest temperature at which the oil is completely miscible with an equal volunieof freshly distilled aniline. Alternatively, Aniline Point is the minimum equilibrium solution temperature for equal volumes of aniline and the lubricant sample. 

Aniline point of any lubricant is a measure of its aromatic content. A lubricant with a low aniline point (therefore having high aromatic content) will tend to attack (solvate and swell) the rubber seals, used in the system to prevent leakage. The sensitivity of a rubber to a lubricating oil depends on the characteristics of the rubber formulation (composition), and for a rubber seal of fixed compraition, the severity of attack increases with decrease in Aniline Point. 

The best way to ascertain the probable action of a lubricating oil on rubber is, of course, to immerse the particular rubber in the oil and observe, any swelling or softening but this is a time consuming exercise and may involve weeks or months. The aniline point of an oil, which can be experimentally measured within hours, therefore, can be used as advance information as to the possible deterioration of rubber sealing, gasket and packing material in the presence of the oil. 

A lubrication of high aniline point is recommended for systems in which rubber seals are being used. Also the lubricants ofalmost same aniline pointsshould be used in a system, as any variation may change the volume of rubber seals and leakage might take place. 

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. 

---

Some empirical formulas have been devised to link the cetane index to the Diesel Index (D.l.) or even directly to the aniline point. We will cite two such formulas here in order to illustrate their comparative values C ... 

Nevertheless, this type of analysis, usually done by chromatography, is not always justified when taking into account the operator s time. Other quicker analyses are used such as FIA (Fluorescent Indicator Analysis) (see paragraph 3.3.5), which give approximate but usually acceptable proportions of saturated, olefinic, and aromatic hydrocarbons. Another way to characterize the aromatic content is to use the solvent s aniline point the lowest temperature at which equal volumes of the solvent and pure aniline are miscible. 

This value characterizes the level of aromatics in non-formulated oils the aniline point is higher for low aromatic contents. 

Benzene content Aniline point Bromine number... 

The different cuts obtained are collected their initial and final distillation temperatures are recorded along with their weights and specific gravities. Other physical characteristics are measured for the light fractions octane number, vapor pressure, molecular weight, PONA, weight per cent sulfur, etc., and, for the heavy fractions, the aniline point, specific gravity, viscosity, sulfur content, and asphaltene content, etc. 

Aniline point NF M 07-021 ISO 2977 ASTMD611 Phase separation temperature of a hydrocarbon/ aniline mixture... 

Association Fran aise de Normalisation Association Fran aise des Techniciens du Petrole i American Institute of Chemical Engineers i American National Standards Institute 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. 

Other methods are also available for the estimation of diesel fuel quaUty. For example, the diesel index (DI) is defined by the relation DI = (A° F X ° API)/100, where A °F is the aniline point in degrees Fahrenheit and °API is the American Petroleum Institute gravity. A high aniline point corresponds to a high proportion of paraffins in the diesel fuel such a fuel has a high diesel index and, therefore, a high cetane number. 

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 and mixed aniline point (DIN 51 775 modified). It is similar to the cloud point test except that the solvent is aniline, a very polar liquid. The aniline point is defined as the temperature at which a mixture of equal parts of aniline and the resin show the beginning of phase separation (i.e. the onset of clouding). Phase separation for aromatic resins occurs between I5°C and below zero for resins with intermediate aromaticity, it lies between 30 and 50°C and for non-aromatic resins, it is 50 to 100°C. Sometimes the mixed aniline point is used. It is similar to the aniline point except that the solvent is a mixture of one part of aniline and one part of w-heptane. The problem of both procedures is that precipitation of resins can be produced before the cloud is generated. 

Proper control of the properties of drilling mud is very important for their preparation and maintenance. Although oil-base muds are substantially different from water-base muds, several basic tests (such as specific weight, API funnel viscosity, API filtration, and retort analysis) are run in the same way. The test interpretations, however, are somewhat different. In addition, oil-base muds have several unique properties, such as temperature sensitivity, emulsion stability, aniline point, and oil coating-water wettability that require other tests. Therefore, testing of water and oil-base muds will be considered separately. 

The oil for an oil-base mud can be diesel oil, kerosene, fuel oil, selected crude oil, or mineral oil. There are several requirements for the oil (1) API gravity = 36° - 37°. (2) flash point = 180°F or above, (3) fire point = 200°F or above, and (4) aniline point = 140°F or above. Emulsifiers are more important in oil-base mud than in water-base mud because contamination on the drilling rig is very likely, and it is very detrimental to oil mud. Thinners, on the other hand, are far more important in water-base mud than in oil-base mud oil is dielectric, so there are no interparticle electric forces to be nullified. 

The simple API gravity test provides valuable information about the quality of a feed. But the shift in API usually signals changes in other feed properties, such as carbon residue and aniline point. Addi tional tests are needed to fully characterize the feed. 

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. 

ASTM D-611 involves heating a 50/50 mixture of the feed sample and aniline until there is only one phase. The mixture is then cooled and the temperature at which the mixture becomes suddenly cloudy is the aniline point. The test senses solubility via a light source that penetrates through the sample. 

The aniline point increases with paraffinicity and decreases with aromaticity. It also increases with molecular w eight. Naphthenes and olefins show values that lie between those for paraffins and aromatics. Typically, an aniline point higher than 200°F (93°C) indicates paraffinicity and an aniline point lower than 150°F (65°C) indicates aromaticity. 

Aniline point is used in some correlations to estimate the aromaticity of gas oil and light stocks. TOTAL S [1] correlation uses aniline point and refractive index. Others, such as n-d-M [2], employ refractive index to characterize FCC feed. 

Similar to aniline point, refractive index (RI) shows how refractive or aromatic a sample is. The higher the RI, the more the aromatics and the less crackable the sample. A feed having an RI of 1.5105 is more difficult to crack than a feed with an RI of 1.4990. The RI can be measured in a lab (ASTM D-1218) or predicted using correlations such as the one published by TOTAL. 

Like aniline point, the K factor differentiates between the highly paraffinic and aromatic stocks. However, within the narrow range (K = 11.5-12.0), the K factor does not correlate between aromatics and naphthenes. Instead, it relates fairly well to the paraffin content (Figure 2-11). The K factor does not provide information as to the ratio of naphthene and paraffin contents. The ratio of naphthenes to paraffins can vary considerably with the same K values (Table 2-8). 

Aniline Point. Feeds with a higher aniline point are aromatic and more paraffinic. The higher the aniline point, the lower the octane. 

Trend the feedstock properties look for changes in the K factor, 1,050°F+ (565°C+), aniline point, refractive index, and °API gravity. The feed endpoint may have been increased to fill the unit. The conversion penalty may be a small price to pay for the increased capacity, but the penalty can be minimized. Verify that the refinery LP reflects current data on yields and product quality. 

Increase in naphthene, olefin, and aromatic concentration, which is indicated by an increase in the refractive index and decreases in aniline point and K factor... 

Track changes in feed metals content, trend the aniline point, and refractive index. 

Trend the feed API gravity, K factor, and aniline point. Verify any changes in paraffin content of the feed. 

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. 

Refractive Index, similar to aniline point, is a quantitative indication of a sample s aromaticity. 

---