Industrial solvents cyclohexane

Cyclohexane is the starting point for making the chemical intermediates cyclohexanol and cyclohexanone. Other minor uses include industrial solvent applications such as cutthig fats, oils, and rubber. Cyclohexane also makes a good paint remover component. 

Bernard AM, deRussis R, Normand JC, et al Evaluation of the subacute nephrotoxicity of cyclohexane and other industrial solvents in the Sprague-Dawley rat. Toxicol Lett 45 271-280, 1989... 

The rates of reaction of OH with methane, deuteriated methanes,228 cyclohexane,229 and 1-bromopropane230 have been measured and the atmospheric implication of the results discussed. The latter study assessed the global warming potential of the industrial solvent 1-bromopropane at 20, 100 and 500 years. 

Thin layer chromatography has been used to evaluate [125] organomercury compounds in industrial effluents. Ci-C6 -alkylmercury chlorides were separated on layers prepared with silica gel plus sodium chloride using as development solvent cyclohexane-acetone-... 

Separation of benzene/cyclohexane mixture is investigated most extensively. This is not surprising because separation of this mixture is very important in practical terms. Benzene is used to produce a broad range of valuable chemical products styrene (polystyrene plastics and synthetic rubber), phenol (phenolic resins), cyclohexane (nylon), aniline, maleic anhydride (polyester resins), alkylbenzenes and chlorobenzenes, drugs, dyes, plastics, and as a solvent. Cyclohexane is used as a solvent in the plastics industry and in the conversion of the intermediate cyclohexanone, a feedstock for nylon precursors such as adipic acid. E-caprolactam, and hexamethylenediamine. Cyclohexane is produced mainly by catalytic hydrogenation of benzene. The unreacted benzene is present in the reactor s effluent stream and must be removed for pure cyclohexane recovery. 

Thin layer chromatography has been used to evaluate [125] organomercury compounds in industrial effluents. Ci-C n-alkylmercury chlorides were separated on layers prepared with silica gel plus sodium chloride using as development solvent cyclohexane-acetone-28% aqueous ammonia (60 40 1). The R, values decrease with increasing carbon chain length and the phenylmercury acetate migrated between the C, and Cj compounds. The spots are detected by spraying with dithizone solution in chloroform. 

The effect of physical processes on reactor performance is more complex than for two-phase systems because both gas-liquid and liquid-solid interphase transport effects may be coupled with the intrinsic rate. The most common types of three-phase reactors are the slurry and trickle-bed reactors. These have found wide applications in the petroleum industry. A slurry reactor is a multi-phase flow reactor in which the reactant gas is bubbled through a solution containing solid catalyst particles. The reactor may operate continuously as a steady flow system with respect to both gas and liquid phases. Alternatively, a fixed charge of liquid is initially added to the stirred vessel, and the gas is continuously added such that the reactor is batch with respect to the liquid phase. This method is used in some hydrogenation reactions such as hydrogenation of oils in a slurry of nickel catalyst particles. Figure 4-15 shows a slurry-type reactor used for polymerization of ethylene in a sluiTy of solid catalyst particles in a solvent of cyclohexane. 

Alicyclic amines are used as pesticides, plasticizers, explosives, inhibitors of metal corrosion and sweetening agents as well as having uses in the pharmaceuticals industry. Aniline hydrogenation has been studied in the literature with the main reaction products cyclohexylamine, dicyclohexylamine, A-phenylcyclohexylamine, diphenylamine, ammonia, benzene, cyclohexane, cyclohexanol and cyclohexanone [1-9], The products formed depend on the catalyst used, reaction temperature, solvent and whether the reaction is performed in gas or liquid phase. For example high temperature, gas-phase aniline hydrogenation over Rh/Al203 produced cyclohexylamine and dicyclohexylamine as the main products [1],... 

According to Coimbra et solvents play a central role in the majority of chemical and pharmaceutical industrial processes. The most used method to obtain artemisinin (1) from A. annua is through the use of organic solvents such as toluene, hexane, cyclohexane, ethanol, chloroform and petroleum ether. Rodrigues et al described a low-cost and industrial scaled procedure that enables artemisinin (1) enhanced yields by using inexpensive and easy steps. Serial extraction techniques allowed a reduction of 65% in solvent consumption. Moreover, the use of ethanol for compound extraction is safer when compared to other solvents. Flash column pre-purification employing silicon dioxide (Zeosil ) as stationary phase provided an enriched artemisinin (1) fraction that precipitated in hexane/ethyl acetate (85/15, v/v) solution. These results indicate the feasibility of producing artemisinin (1) at final cost lowered by almost threefold when compared to classical procedures. 

The selective oxidation of saturated hydrocarbons is a reaction of high industrial importance. Besides a variety of other oxidants, hydrogen peroxide as a very clean oxidant has also been used for these purposes . As an example, in 1989 Moiseev and coworkers reported on the vanadium(V)-catalyzed oxidation of cyclohexane with hydrogen peroxide (Scheme 146) . When the reaction was carried out in acetic acid cyclohexanol and cyclohexanone were formed, bnt conversions were very poor and did not exceed 13%. Employing CF3COOH as solvent, complete conversions could be obtained within 5 min-ntes. Here, cyclohexyl trifluoroacetate was the main product (85% of the products formed) resulting from the reaction of cyclohexanol (the primary product of the oxidation) with CF3COOH. 

The dealkylation of toluene is a prime source of benzene, accounting for about one-half of toluene consumption. The production of diisocyanates from toluene is increasing. As a component of fuels, the use of toluene is lessening. Toluene takes part in several industrially important syntheses. The hydrogenation of toluene yields methyl cyclohexane (C6HnCH3), a solvent for fats, oils, rubbers, and waves. Trinitrotoluene [TNT, CH3C6H2(N02)3] is a major component of several explosives. When reacted with sulfuric acid, toluene yields o- and p-toluene sulfonic acids... 

Uses The alicyclic hydrocarbons have numerous industrial applications. Cyclopropane (C3H6) is used as an anesthetic. Cyclohexane (CgH ) is used as a chemical intermediate as an organic solvent for oils, fats, waxes, and resins and for the extraction of essential oils in perfume manufacturing industries. Cyclohexene (C6H10) is used in the manufacture of maleic acid, cyclohexane carboxylic acid, and adipic acid. Methyl cyclohexane (C7H14) is used for the production of organic synthetics such as cellulose ethers. These compounds are used in different industries such as adipic acid makers, benzene makers, fat processors, fungicide makers, lacquerers, nylon makers, oil processors, paint removers, plastic molders, resin makers, rubber makers, varnish removers, and wax makers. 

Industrial polymerisation processes with the use of titanium-, cobalt- and nickel-based aluminium alkyl-activated Ziegler-Natta catalysts, which are employed for the manufacture of cis- 1,4-poly butadiene, involve a solution polymerisation in low-boiling aromatic hydrocarbons such as toluene or in a mixture of aromatic and aliphatic hydrocarbons such as n-heptane or cyclohexane. The polymerisation is carried out in an anhydrous hydrocarbon solvent system. The proper ratio of butadiene monomer and solvent is blended and then completely dried in the tower, followed by molecular sieves. The alkyla-luminium activator is added, the mixture is agitated and then the transition metal precatalyst is introduced. This blend then passes through a series of reactors in a cascade system in which highly exothermic polymerisation occurs. Therefore, the reaction vessels are cooled to slightly below room temperature. 

Recently, a ruthenium-catalysed oxidation in water was published by d Alessandro et al. [34]. Water can be regarded as an environmentally friendly solvent which, because it is inert, reduces the risk of explosions. The oxidation of cyclohexane directly to adipic acid was performed using ruthenium catalysts bearing water-soluble phthalocyanine ligands RuPcS (where PcS is tetra-sodium 2,3-tetrasulfophthalocyaninato) with KHSOs (Eq. 4). However we note that very low TONs were observed and the use of KHSOs as a primary oxidant is not viable for industrial-scale oxidations. 

Synonyms and trade names benzene, benzine, benzol, aromatic hydrocarbon Uses and exposure Benzene is a colorless, flammable liquid with a pleasant odor. It is used as a solvent in many industries, such as rubber and shoe manufacturing and in the production of other important substances such as styrene, phenol, and cyclohexane. It is essential in the manufacture of detergents, pesticides, solvents, and paint removers. It is present in fuels such as in gasoline up to the level of 5%. There are several uses for benzene. ... 

The most common sc-fluid for industrial processing and benchtop research is supercritical carbon dioxide, chosen because of its moderate and easily attained critical temperature and pressure and its non-toxicity. Reactions in SC-CO2 produce similar results as reactions in nonpolar organic solvents. Its solvent polarity, empirically determined using solvatochromic dyes as polarity indicators (see Section 7.4), corresponds to that of hydrocarbons such as cyclohexane [221, 222]. Carbon dioxide has no dipole moment and only a small quadrupole moment, a small polarizabihty volume, and a low relative permittivity (er = 1.4-1.6 at 40 °C and 108-300 bar) [221, 223]. Thus, SC-CO2 is only suitable as a solvent for nonpolar substances, which unfortunately imposes considerable limitations on its practical applications. To overcome this limitation, more polar co-solvents (modifiers) such as methanol can be added to SC-CO2. 

The selective oxidation of cyclohexane to cyclohexanol and cyclohexanone has been studied by Suo and co-workers [395,396]. This reaction is a key process in the chemical industry, for the oxidation products of cyclohexane, via cyclohexanol and cyclohexanone, are important intermediates in the manufacture of nylon-6 and nylon-66 polymers and are also used as solvents for lacquers, shellacs and varnishes as well as stabilisers and homogenisers for soaps and S3mthetic detergent emulsions. 

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