Aromatics removal from aliphatics

Sulfolane, another highly polar solvent, is used to separate aromatic hydrocarbons from aliphatic hydrocarbons [10]. The extraction process first developed by Shell Oil in 1959 and which is referred to as the Sulfolane process is used worldwide. The solvency of sulfolane for certain fatty acids and fatty acid esters is the basis for upgrading animal and vegetable fatty acids used in food products, paints, plastics, resins, and soaps. Aqueous solutions containing 30-70 wt% sulfolane are used to remove lignin from wood chips [11]. Sulfolane is used to remove acidic components like hydrogen sulfide and carbon dioxide from gas feed stocks. 

Carbon dioxide Sulfur dioxide Aliphatic hydrocarbons Aromatic hydrocarbons Cholinesterase inhibitors Paraquat Lead Arsenic Mercury Removal from exposure and administer oxygen Removal from exposure Removal from exposure Removal from exposure Atropine, pralidoxime Gastric lavage and dialysis Dimercaprol, penicillamine Dimercaprol, penicillamine Dimercaprol (elemental), penicillamine, dimercaprol (inorganic salts)... 

Drizo A variation of the glycol process for removing water vapor from natural gas, in which the water is removed from the glycol by stripping with a hydrocarbon solvent, typically a mixture of pentanes and heavier aliphatic hydrocarbons. The process also removes aromatic hydrocarbons. Last traces of water are removed from the triethylene glycol by stripping with toluene in a separate, closed loop. Invented in 1966 by J. C. Arnold, R. L. Pearce, and H. G. Scholten at the Dow Chemical Company. Twenty units were operating in 1990. U.S. Patent 3,349,544. 

MLDW [Mobil lube dewaxing] A catalytic process for removing waxes (long-chain linear aliphatic hydrocarbons and alkyl aromatic hydrocarbons) from lubricating oil. Developed by Mobil Research Development Corporation and operated at Mobil Oil refineries since 1981. Eight units were operating in 1991. 

Utilizing prochiral a,a-disubstituted Michael acceptors, the Stetter reaction catalyzed by 76a has proven to be both enantio- and diastereoselective, allowing control of the formation of contiguous stereocenters Eq. 8 [73]. It is noteworthy that a substantial increase in diastereoselectivity is observed, from 3 1 to 15 1, when HMDS, the conjugate acid formed upon pre-catalyst deprotonation, is removed from the reaction vessel. Reproducible results and comparable enantioselectivities are observed with free carbenes for example, free carbene 95 provides 94 in 15 1 diastereoselectivity. The reaction scope is quite general and tolerates both aromatic and aliphatic aldehydes (Table 9). 

Similar experiments in this study using benzene and naphthalene as reactants show that these aromatics (commonly found in diesel) result in carbon formation at conditions even further removed from equilibrium (Figure 10). Similar results were obtained by Houseman et al in the ATR of No. 2 fuel oil (in this study, the equilibrium calculations were based on data for graphitic carbon). They reported that both aromatic and olefinic compounds are more prone to form carbon than aliphatic compounds at conditions thermodynamically removed from those that favor carbon formation. 

A continuous distillation process has been studied for the production of high boiling esters from intermediate boiling polyhvdric alcohols and low boiling monocarboxylic aliphatic or aromatic acids. The water of reaction and some of the organic acid were continuously removed from the base of the column. 

Several methods, involving solvent extraction or destructive hydrogenation, can accomplish the removal of aromatic hydrocarbons from naphtha. By destructive hydrodegation methods, aromatic hydrocarbon rings are first ruptured and then saturated with hydrogen, which converts aromatic hydrocarbons into the odorless, straight-chain paraffinic hydrocarbons required in aliphatic solvents. 

The first large-scale application of solvent extraction was the removal of aromatics from kerosene to improve its burning properties. Solvent extraction is used for processing jet fuel and lubricating oil, which require a low aromatic content. Solvent extraction is used equally extensively to meet the ever-increasing demand for high-purity aromatics such as benzene, toluene, and xylene (BTX) as feedstocks for the petrochemical industry. The separation of aromatics from aliphatics is one of the largest applications of solvent extraction. 

The dehydrohalogenation of a yQ-chloroalkylbenzene is readily accomplished by refluxing with excess aqueous methanolic potassium hydroxide. Substituted a-alkylstyrenes which are difficult to obtain by other methods are prepared in this way by a two-step process involving catalytic condensation of aromatic compounds with aliphatic chlorohydrins followed by removal of hydrogen halide from the resulting haloalkylated derivatives. ... 

Based on the principles of n-complexation, we have already developed a number of new sorbents for a number of applications. These include sorbents for (a) olefin/paraffin separations [9-12], (b) diene/olefin separation or purification (i.e., removal of trace amounts of dienes from olefins) [13], and (c) aromatics/aliphatics separation and purification (i.e., removal of trace amounts of aromatics from aliphatics [14]. Throughout this work, we have used molecular orbital calculations to obtain a basic understanding for the bonding between the sorbates and sorbent surfaces, and further, to develop a methodology for predicting and designing n-complexation sorbents for targeted molecules (e.g. Ref 11). 

Thus, the permeation of hydrocarbons in polymer membranes is governed by the basic regularities typical of permeation of low MW penetrants, modified however by certain peculiarities related to the stmcture and shape of hydrocarbon molecules. We will now discuss the physicochemical regularities of hydrocarbon separation and removal using polymer membranes, by trying to reveal the relationship between the chemical stmcture of polymers and their separation properties with respect to mixtures containing hydrocarbons. It follows from literary data that mbbery polymers are mainly used in gas/vapor separation processes for selective separation of hydrocarbon vapors from their mixtures with air as well as in pervaporation processes for the removal of hydrocarbons from their aqueous solutions. In practice, glassy polymers are used for separation of olefins and paraffins as well as for separation of aromatic, ahcyclic, and aliphatic hydrocarbons. 

P-450s carry out aliphatic and aromatic hydroxylat-ions, aromatic epoxidations (leading to stable epoxides like dieldrin from aldrin, or arene oxides), 0-, N-, and S-dealkylations and oxidations, oxidative deaminations, and desulfurations among other reactions. Although the primary evolutionary role of the P-450 enzymes is to convert hydrophobic xenobiotics into more hydrophilic compounds and enhance their removal from the body, P-450s also catalyze reactions that lead to more reactive (and hence toxic) compounds. Several xenobiotics are converted into potential carcinogens via the cytochrome P-450 system. 

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