Asphaltenes Oxidation

Trimesic acid is also referred to as 5-carboxyisophthahc acid [554-95-0] trimesinic acid, or trimesitinic acid. It is a smaH-volume, synthetic chemical and is sold commercially. Traces of trimesic acid as well as other aromatic carboxyUc acids with three or more carboxyUc acid groups are found in lignite (137), and when various types of coals or coal components such as brown coal, asphaltene, or coal-tar pitch are oxidized. 

Cap Gas. Both crude and asphaltene-free oil were used to determine the consequences of low-temperature oxidation. It was found that the oxygen content in an artificial gas cap was completely consumed by chemical reactions (i.e., oxidation, condensation, and water formation) before the asphaltene content had reached equilibrium. 

Figure 18.13 Experimental and calculated concentrations of Coke (COK) "A , Asphaltene (ASP) o" and Heavy Oil + Light Oil (HO+LO) "a" at 50 °C for the low temperature oxidation of North Bodo oil sands bitumen using model l.

Aromatics Resins — Asphaltenes — coke where the resin + asphaltene content remains constant and asphaltenes are the main precursors of coke. The same observations have been made in low-temperature oxidation experiments (6). 

The postulated and sufficiently proven notion that asphaltenes are oxidation products of resins and that resins are oxidation products of oil (11) sort of makes the probability of finding oils whose actual resin concentration is less than their critical resin concentration small. In other... 

Asphalt chemicals, ethyleneamines application, 8 500t, 506 Asphalt emulsifier amine oxides, 2 473 fatty acid amides, 2 458 Asphalt emulsions, 10 131 Asphaltenes, in petroleum vacuum residua, 18 589-590 Asphyxiants, 21 836 Aspirating aerators, 26 165-169 compressed, 26 168-169 propeller driven, 26 168 submersible, 26 169, 170t subsurface, 26 168 Aspiratory, 11 236-237 Aspirin, 4 103-104, 104t, 701 22 17-21. See also Acetylsalicylic acid as trade name, 22 19 for cancer prevention, 2 826 Aspirin resistance, 4 104 ASP oil recovery process, 23 532-533 Assay format, competitive, 14 142 Assay limits, in Investigational New Drug Applications, 18 692 Assays, for silver, 22 650. See also... 

The basic structures of resins and asphaltenes are similar. Both can be formed by oxidation of polycyclic aromatic hydrocarbons. On the other hand, both can be reduced to hydrocarbons by hydrogenation, which yields moderate to large hydrocarbon molecules, hydrogen sulfide, and water. Further, resins can be converted to asphaltenes by oxidation. 

Bitumen asphaltenes undergo a variety of simple chemical conversions. For example, asphaltenes can be oxidized, sulfonated, sulfomethylated, halogenated, and phosphoryl-ated. The net result is the introduction of functional entities into the asphaltene structure which confer interesting properties on the products for which a variety of uses are proposed. 

Sulfonation and Sulfomethylation. Sulfomethylation and/or sul-fonation of the asphaltenes are not feasible, but oxidation of the asphaltenes produces the necessary functional groups which allow sulfomethylation and sulfonation (5). Confirmation of this can be obtained from three sources ... 

These sulfomethylated and sulfonated oxidized asphaltenes even remain in solution after acidification with 5% aqueous hydrochloric acid to a pH of 2.5-3.0 while the parent-oxidized asphaltenes can be precipitated from alkaline solution by acidification to a pH of 6.5. 

Phosphorylation. Attempts to phosphorylate asphaltenes with phosphoric acid, phosphorous trichloride, or phosphorous oxychloride were partially successful insofar as it is possible to introduce up to 3% w/w phosphorous into the asphaltenes (14). However, application of these same reagents to oxidized asphaltenes increases the phosporous quite markedly to 10% w/w in the products (14). Subsequent reaction of the phosphorous-containing products is necessary to counteract the acidity of the phosphorous moieties. 

The stability of the products from coal-derived syncrudes must be examined carefully. Many unique compounds are present in these syncrudes peri-condensed aromatics and naphthenes, oxygen compounds, and asphaltene-like hydrocabons. Traces of these compounds may remain in the hydrotreated product and their effect on jet, thermal, and oxidation stabilities cannot be predicted from the behavior of petroleum products. 

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