Solvents, production, extractive

CAimHPFe] RhCl(PPh3)3 Olefins 48 bar, 50 °C scC02 as co-solvent, product extracted [28] with scC02. 

CnCiim] [various] [C4ClPy][Tf2N] [IrCl(cod)]2 + PN-ligand Imines 30-100 bar, 0-40°C scC02 as co-solvent product extracted with scC02. [11]... 

C4Ciim][PF6] Mn(salen) complex NaOCl Asymmetric epoxidation CH2C12 as co-solvent reaction proceeds faster in the ionic liquid relative to conventional solvents product extracted with hexane catalyst was recycled 4 times, activity and selectivity slowly decrease. [48]... 

C.CjimHPFe] 0s04 NMO Enantioselective dihydroxylation of olefins with H20 and t-butanol as co-solvents products extracted with Et20 addition of an amine ligand significantly improves catalyst retention catalyst recycled 5 times, activity decreases only slowly. [62]... 

C4)4N][BF4] [C4C4pyrr] [BF4] PdCl2 k2co3 Et3N 90 °C. Ligand-free arylation of butyl acrylate with iodo- and bromo benzene biphasic system with either water or toluene as co-solvent product extracted with hexane. [64]... 

Carbon disulphide is an excellent solvent for fats, oils, rubber, sulphur, bromine and iodine, and is used industrially as a solvent for extraction. It is also used in the production of viscose silk, when added to wood cellulose impregnated with sodium hydroxide solution, a viscous solution of cellulose xanthate is formed, and this can be extruded through a fine nozzle into acid, which decomposes the xanthate to give a glossy thread of cellulose. 

Endo-exo product mixtures were isolated using the following procedure. A solution of cyclopentadiene (concentration 2-10" M in water and 0.4 M in oiganic solvents) and the dienophile (concentration 1-5 mM) in the appropriate solvent, eventually containing a 0.01 M concentration of catalyst, was stirred at 25 C until the UV-absorption of the dienophile had disappeared. The reaction mixture (diluted with water in the case of the organic solvents) was extracted with ether. The ether layer was washed with water and dried over sodium sulfate. After the evaporation of the ether the... 

Alkvl Azides from Alkyl Bromides and Sodium Azide General procedure for the synthesis of alkyl azides. In a typical experiment, benzyl bromide (360 mg, 2.1 mmol) in petroleum ether (3 mL) and sodium azide (180 mg, 2.76 mmol) in water (3 mL) are admixed in a round-bottomed flask. To this stirred solution, pillared clay (100 mg) is added and the reaction mixture is refluxed with constant stirring at 90-100 C until all the starting material is consumed, as obsen/ed by thin layer chromatographv using pure hexane as solvent. The reaction is quenched with water and the product extracted into ether. The ether extracts are washed with water and the organic layer dried over sodium sulfate. The removal of solvent under reduced pressure affords the pure alkyl azides as confirmed by the spectral analysis. ... 

A solution of benzyl indole-5-carboxylate(1.0g, 3.98 mmol) and methyl 4-(bro-momethyl)-3-methoxybenzoate (2.06 g, 7.97 mmol) in dry DMF (10 ml) was heated at 80°C for 24 h. The reaction solution was cooled, poured into water (100 ml) and the product extracted with EtOAc (3 x 75 ml). The extract was washed with water and brine and dried over MgSO, . The product was obtained by evaporation of the solvent and purified by chromatography on silica gel using 1 4 EtOAc/hexane for elution. The yield was 1.11 g (32%) and some of the indole (30%) was recovered unreacted. 

Dual solvent fractional extraction (Fig. 7b) makes use of the selectivity of two solvents (A and B) with respect to consolute components C and D, as defined in equation 7. The two solvents enter the extractor at opposite ends of the cascade and the two consolute components enter at some point within the cascade. Solvent recovery is usually an important feature of dual solvent fractional extraction and provision may also be made for reflux of part of the product streams containing C or D. Simplified graphical and analytical procedures for calculation of stages for dual solvent extraction are available (5) for the cases where is constant and the two solvents A and B are not significantly miscible. In general, the accurate calculation of stages is time-consuming (28) but a computer technique has been developed (56). 

Aromatic Hydrocarbons. Sulfolane is used principally as a solvent for extraction of benzene, toluene, and xylene from mixtures containing aHphatic hydrocarbons (33—37). The sulfolane process was introduced in 1959 by SheU Development Company, and that process is Hcensed by Universal OH Products. A sulfolane extraction process is also Hcensed by the Atlantic Richfield Company. In 1994, worldwide consumption was estimated at ca 6974 t/yr of sulfolane for 137 sulfolane extraction units (see Bix processes Extraction, liquid-liquid Xylenes and ethylbenzene). 

Cls-1 -dlmethyl-3-phenylazlridlne (2) To a coofed and well stirred suspension of LAH (3 S g, 0 1 mol) m Et20 (100 mL) was added dropwise a solution of 2 2-dichloro-N methyl propiophenone imme 1 (10 8 g, 0 05 mol) m Et20 (100 mL) After overnight reflux the mixture was poured with caution onto ice water aixf the product extracted with Et20 Evaporation ot the solvent gave 8 21 g of 2 (84%), bp 79 82°C... 

The cyclic steady state SMB performance is characterized by four parameters purity, recovery, solvent consumption, and adsorbent productivity. Extract (raffinate) purity is the ratio between the concentration of the more retained component (less retained) and the total concentration of the two species in the extract (raffinate). The recovery is the amount of the target species obtained in the desired product stream per total amount of the same species fed into the system. Solvent consumption is the total amount of solvent used (in eluent and feed) per unit of racemic amount treated. Productivity is the amount of racemic mixture treated per volume of adsorbent bed and per unit of time. 

Biotechnological processes may be divided into fermentation processes and biotransformations. In a fermentation process, products are formed from components in the fermentation broth, as primary or secondary metabolites, by microorganisms or higher cells. Product examples are amino acids, vitamins, or antibiotics such as penicillin or cephalosporin. In these cases, co-solvents are sometimes used for in situ product extraction. 

Acetonitrile and hydrogen cyanide are hy-products that may he recovered for sale. Acetonitrile (CH3CN) is a high polarity aprotic solvent used in DNA synthesizers, high performance liquid chromatography (HPLC), and electrochemistry. It is an important solvent for extracting butadiene from C4 streams. Table 8-1 shows the specifications of acrylonitrile, HCN, and acetonitrile. ... 

In a two-phase system (Figure 2.5c), the organic (water immiscible) solvent may be used as product extractant. In addition, recirculation of the organic phase can serve to transfer oxygen and to mix the aqueous phase. 

Today SCFs are used for natural product extractions, chromatographic separations, pollution prevention, material processing and as solvents for chemical reactions.[75-77] Chemical applications include catalysis, polymerization, enzymatic reactions and organic synthesis. 

The first application of ionic hquids for salen complexes dealt with the epoxidation of alkenes [14]. Jacobsen s Mn complex was immobilized in [bmimjlPFe] and different alkenes were epoxidized with aqueous NaOCl solution at 0 °C. As the ionic solvent sohdified at this temperature, dichloromethane was used as a cosolvent. The recychng procedure consisted of washing with water, evaporation of dichloromethane, and product extraction with hexane. The results (Table 3) were excellent and only a slow decay in activity and enantioselectivity was detected after several cycles. 

Acetochlor and its metabolites are extracted from plant and animal materials with aqueous acetonitrile. After filtration and evaporation of the solvent, the extracted residue is hydrolyzed with base, and the hydrolysis products, EMA and HEMA (Figure 1), are steam distilled into dilute acid. The distillate is adjusted to a basic pH, and EMA and HEMA are extracted with dichloromethane. EMA and HEMA are partitioned into aqueous-methanolic HCl solution. Following separation from dichloromethane, additional methanol is added, and HEMA is converted to methylated HEMA (MEMA) over 12 h. The pH of the sample solution is adjusted to the range of the HPLC mobile phase, and EMA and MEMA are separated by reversed phase HPLC and quantitated using electrochemical detection. 

With the reaction performance improved, attention turned to isolation of 3. The work-up of this reaction was complicated by the solubility of TH F in water and the low solubility of 3 in most organic solvents. Using extraction to remove residual magnesium salts would have severely limited volumetric productivity. We found that 3 could be isolated by quenching the reaction into aqueous HC1. Crude 3 was isolated after concentrating the organic layer. Residual TH F and magnesium salts were then removed by recrystallization from AcOH/water with less than 1% loss of 3. 

The product workup consisted of continuously extracting the filter cake with tetrahydrofuran (THF) and combining the THF and filtrate to make up a sample for distillation. In some experiments the THF extracted filter cake was extracted with pyridine and the pyridine extract was included in the liquid products. Extraction with pyridine increased coal conversion to soluble products by an average of 1.6 weight percent. The hot filtrate-THF-pyridine extract was distilled. Distillation cuts were made to give the following fractions, THF (b.p. <100 C), light oil (b.p. 100-232 C), solvent (b.p. 232-482), and SRC (distillation residue, b.p. >482 C). 

The isolation of product is usually possible after evaporation of the solvent and extraction with hexane, ether, or toluene. Supported versions, for example on polystyrene grafted with PPh2 groups, have proved unsatisfactory because the rate of deactivation is greatly enhanced under these conditions [37]. Asymmetric versions exist, but the ee-values tend to be lower than in the Rh series [38]. With acid to neutralize the basic N lone pair, imine reduction is fast. Should it be necessary to remove the catalyst from solutions in order to isolate a strictly metal-free product, a resin containing a thiol group should prove satisfactory. A thiol group in the substrate deactivates the catalyst, however. 

The direct high yield synthesis of oxaspiropentanes from almost any type of aldehyde or ketone represents a particularly useful transformation because of the high reactivity of such compounds. This approach proves to be exceptionally simple. The DMSO reaction mixture can be directly extracted with pentane or hexane, the hydrocarbon solvent removed and the product isolated by distillation or crystallization. Since diphenyl sulfide is the only by-product extracted with the oxaspiropentane, the mixture can normally be used for most further synthetic transformations. Table 2 summarizes some of the oxaspiropentanes prepared by this method. 

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