Reaction diluent

The catalytic vapor-phase oxidation of propylene is generally carried out in a fixed-bed multitube reactor at near atmospheric pressures and elevated temperatures (ca 350°C) molten salt is used for temperature control. Air is commonly used as the oxygen source and steam is added to suppress the formation of flammable gas mixtures. Operation can be single pass or a recycle stream may be employed. Recent interest has focused on improving process efficiency and minimizing process wastes by defining process improvements that use recycle of process gas streams and/or use of new reaction diluents (20-24). 

Almost all of the cyclohexane that is produced in concentrated form is used as a raw material in the first step of nylon-6 and nylon-6,6 manufacture. Cyclohexane also is an excellent solvent for cellulose ethers, resins, waxes (qv), fats, oils, bitumen, and mbber (see Cellulose ethers Resins, natural Fats AND FATTY OILS Rubber, NATURAL). When used as a solvent, it usually is in admixture with other hydrocarbons. However, a small amount is used as a reaction diluent in polymer processes. 

Generally, monochloroacetic acid [79-11-8] (MCA) is added to the reaction slurry containing sufficient excess sodium hydroxide to neutralize the MCA and effect its reaction. The use of esters of MCA has also been reported (52). Common reaction diluents are isopropyl alcohol, /-butyl alcohol, or ethyl alcohol (53,54). Dimethoxyethane has also been reported to be effective (55). The product is isolated and washed with aqueous alcohol or acetone to remove by-product salts. Unpurified cmde grades are generally prepared in the absence of diluents (56—59). 

In the suspension process, which was the first method to be commercially developed, propylene is charged into the polymerisation vessel under pressure whilst the catalyst solution and the reaction diluent (usually naphtha) are metered in separately. In batch processes reaction is carried out at temperatures of about 60°C for approximately 1-4 hours. In a typical process an 80-85% conversion to polymer is obtained. Since the reaction is carried out well below the polymer melting point the process involves a form of suspension rather than solution polymerisation. The polymer molecular weight can be controlled in a variety of... 

Salicylanilide is ordinarily made by reacting salicylic acid with aniline in the presence of phosphorus trichloride at an elevated temperature. The theoretical proportions of reactants are usually employed for best results, that is, one mol each of aniline and salicylic acid to a third of a mol of phosphorus trichloride. An improved process employs an inert organic solvent as a reaction diluent. 

The phase transfer catalyzed alkylation reaction of dodecyl phenyl glycidyl ether (DPGE) with hydroxyethyl cellulose (HEC) was studied as a mechanistic model for the general PTC reaction with cellulose ethers. In this way, the most effective phase transfer catalysts and optimum reaction concentrations could be identified. As a model cellulose ether, CELLOSIZE HEC11 was chosen, and the phase transfer catalysts chosen for evaluation were aqueous solutions of choline hydroxide, tetramethyl-, tetrabutyl-, tetrahexyl-, and benzyltrimethylammonium hydroxides. The molar A/HEC ratio (molar ratio of alkali to HEC) used was 0.50, the diluent to HEC (D/HEC) weight ratio was 7.4, and the reaction diluent was aqueous /-butyl alcohol. Because some of the quaternary ammonium hydroxide charges would be accompanied by large additions of water, the initial water content of the diluent was adjusted so that the final diluent composition would be about 14.4% water in /-butyl alcohol. The results of these experiments are summarized in Table 2. 

Theoretically, catalytic distillation can overcome limitations in a typical two-step process consisting of reaction followed by distillation or separation. Often, a two-step process is limited by chemical equilibrium, heat transfer, mass transfer, or some combination of these. Catalytic distillation can overcome many of these constraints by simultaneously separating products from reactants, maintaining nearly isothermal operation and lowering the external ratio of reaction diluents. 

The Cr/aluminophosphate catalysts exhibit a "fast kinetics profile relative to the profile of Cr/silica. That is, the polymerization rate of Cr/AIPO4 develops almost immediately with no induction time [637], The polymerization rate rises for about 10-20 min, and then declines during the rest of the 1-2-h run. Figure 168 shows an example of the reaction kinetics, when the catalyst had a P/Al atomic ratio of 0.8 and was activated at 700 °C. The rapid development of polymerization suggests that the initiation steps are faster on Cr/aluminophosphate catalysts than on Cr/silica catalysts. This difference could indicate faster reduction, or alkylation, or that the redox by-products, such as formaldehyde, are more quickly removed from the reaction diluent. These aluminophosphate supports are usually better adsorbents for polar compounds than silica activated at 700 °C, and this difference may contribute to the kinetics profile. 

Commercial polymerization processes using soluble catalysts are mostly those in which the lower-crystallinity polymers produced are soluble in the reaction diluent (e.g., elastomers and very low-density ethylene copolymers) or which operate at temperatures above the melting point of the polymer. In these solution processes, the reaction diluent is volatilized and the polymer recovered for compounding and pelletization. 

Uses Extraction solvent for veg. oils, animal oils, essential oils solvent for fast-drying adhesives, lacquers chem. reaction medium f.p. depressant reaction diluent for polyolefin prod. cleaning agent release agent Manuf./Distrib. Aldrich http //www.sigma-aldrich.com ChevronPhillips http //www.cpchem.com, Fluka http //www.sigma-aldrich.com, Romil Ltd http //www.romii.com Trade Name Synonyms Calumet Isohexane [Calumet Lubricants... 

Bromochloromethane Diethoxymethane solvent, reaction/diluent pesticides Butyrolactone solvent, reaction aerosols Methylal... 

An aromatic hydrocarbon consisting of six carbon atoms and six hydrogen atoms arranged in a hexagonal ring structure. It is used extensively in the petrochemical industry as a chemical intermediate and reaction diluent and in some applications as a solvent. Benzene is a toxic substance, and proper safety precautions should be observed in handling it. 

The viscosity of a resin system can be reduced by the addition of a diluent, which can be non-reactive (e.g. dibutyl phthalate, benzyl alcohol and furfuryl alcohol) or reactive (a low molecular weight epoxide, triphenyl phosphite or x-butyrolactone). The x-butyrolactone can, for example, act as a solvent for a catalyst system used in a solventless system and take part in the reaction. Diluents tend to be rather volatile and could be partially lost in cure systems operating under a vacuum. Flexibilizers can impart toughness but at the expense of mechanical properties, chemical resistance and heat resistance. 

Oligomer urethane acrylate (LR 8739) and photoinitiator Irgacure 184 were obtained from IAEA. Reaction diluents 2-methoxy ethyl acrylate (MEA, Tg = -110°C), 2-ethylhexyl acrylate (EHA, Tg = -50°C), 2-hydroxy ethyl methacrylate (HEMA, Tg = 55°C), N-vinyl pyrrolidone (NVP, Tg = 175°C), tripropylene glycol diacrylate (TPGDA, Tg = 90°C), and trimethylol propane triacrylate (TMPTA, Tg 250°C) were used as procured from E, Merck without any further purification. 

Styrene is a reaction diluent. with most aromatic solvents. 

Polyesters organic acids combined with polybasic alcohols. Styrene is a reaction diluent PR R R... 

This technology accoxmts for an annual production of 4-5 million tons of HDPE. The process involves polymerization of ethylene at temperatures below the melting point of the polymer using a solid catalyst to form solid polymer particles suspended in an inert hydrocarbon diluent. Recovery of polymer (by filtration, centrifugation, or flashing) is economic. The chromium oxide-on-silica catalyst developed by Phillips yields polymers which can be easily extruded and blow-moulded. The process is unable to produce copolymers of density below 0.937 g/cm. For a density of 0.92 g/ cm or below, the polymer swells, becomes sticky, and starts to dissolve in the reaction diluent. 

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