Reactors separatory

General procedure for C-S bond formation. A 50 mL of reactor was charged with 232.5 mg (0.25 mm) of POPdl, 1.36 g (12.0 mmol) of 3-chloropyridine, 1.18 g (10.0 mmol) of 1-hexanethiol and 1.92 g (20.0 mmol) of NaO-tBu in 15.0 mL of toluene. The resulting mixture was refluxed for 16 h before the mixture was cooled to room temperature and quenched with 100 mL of H20. The mixture was transferred to a separatory funnel, and extracted with EtOAc (2 X 200 mL). The layers were separated, and organic layer was washed with H20 (100 mL), brine (150 mL), and dried over MgS04, filtered, and the solvents removed from the filtrate by rotary evaporation. The final product was chromatographed on silica gel using ethyl acetate/hexane (5% volume ratio) as eluant. The eluate was concentrated by rotary evaporation to yield 1.90 g (97% yield) of 3-hexylthiopyridine. 

The reaction is maintained at isothermal conditions. The effluent from the reactor is allowed to pass to a separatory vessel in which unconverted ethylene is removed for recycling. The molten polyethylene gets chilled below its crystalline Melting point. 

Laboratory studies of the rearrangement process began with semi-continuous operation in a single, 200-mL, glass reactor, feeding 1 as a liquid and simultaneous distillation of 2,5-DHF, crotonaldehyde and unreacted 1. Catalyst recovery was performed as needed in a separatory funnel with n-octane as the extraction solvent. Further laboratory development was performed with one or more 1000-mL continuous reactors in series and catalyst recovery used a laboratory-scale, reciprocating-plate, counter-current, continuous extractor (Karr extractor). Final scale-up was to a semiworks plant (capacity ca. 4500 kg/day) using three, stainless steel, continuous stirred tank reactors (CSTR). 

A reactor charged with the step 4 product, 75 ml of CH2CI2, and 10.8 ml of pyridine was treated with dropwise addition of 22.5 ml of 1.94 M solution of phosgene in toluene (43.6 mmol) at ambient temperature. The mixture stirred for 3.5 hours and was then diluted with 500 ml of CH2C12 and transferred into a separatory funnel. The mixture was extracted with 0.2 M hydrochloric acid, the organic phase dried over MgS04, concentrated to 150 ml, and precipitated by pouring into 750 ml of hexane and the product isolated. 

Arthur Humphrey Integration is key here. I say that because I m stunned to hear Jim Douglas talk about these new separatory reactors. We heard about the first extractive fermentation in 1970, assuming that you will consider a fermentation a reaction. Even the first volume of Richardson and Coulson has an example of choosing the optimum ratio of extractant to reactant. I don t think that s new. 

Two liquid phases may be contacted in different ways to achieve separation. In the laboratory, the simplest example of LLE involves the use of a separatory funnel where a feed mixture, perhaps an aqueous phase from a reactor, is contacted with several washes of solvent (say, diethyl ether) to extract a solute. If the same aqueous phase is contacted repeatedly with fresh amounts of extracting solvent, such a process is said to be crosscurrent. 

Ultra high purity N2 (ca. 50 mL) was added after each sampling to restore pressure to the reactor. Each sample was cooled to room temperature in an ice bath, the pH measured and the sample extracted with 3x5 mL of dichloromethane (EM Science, Gibbstown, NJ) containing 500 ppm of 4-methylthiazole (Aldrich Chemical, Milwaukee, WI) as an internal standard in a 150 mL separatory funnel. The dichloromethane fraction was dried with anhydrous magnesium sulfate (Fisher Scientific, Fairlawn, NJ), filtered and evaporated to 0.5 to 1.0 mL volume under a stream of high purity nitrogen. 

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