Butanol-water mixtures

A typical penicillin broth contains 20-35 mg/1 of antibiotic. Filtration is used to remove mycelial biomass from fermentation broth. The filtration may be subjected to filter aided polymers. Neutralisation of penicillin at pH 2-3 is required. Amyl acetate or butyl acetate is used as an organic solvent to remove most of the product from the fermentation broth. Finally, penicillin is removed as sodium penicillin and precipitated by a butanol-water mixture. 

Mono-, di-, and trisubstituted olefins undergo osmium-catalyzed enantioselective dihydroxylation in the presence of the (R)-proline-substituted hydroquinidine 3.9 to give diols in 67-95% yields and in 78-99% ee.75 Using potassium osmate(VI) as the catalyst and potassium carbonate as the base in a tm-butanol/water mixture as the solvent, olefins are dihydroxylated stereo- and enantioselectively in the presence of 3.9 and potassium ferricyanide with sodium chlorite as the stoichiometric oxidant the yields and enantiomeric excesses of the... 

In fact, Everett et al. (1995, 1996) have reported the scavenging of N02 by 3-CAR, and their results indicate that the reaction proceeds via electron transfer only and no radical addition occurs. The electron transfer was shown to proceed with a rate constant of 1.1 x 108 M 1 s 1 in tcrt-butanol/ water mixtures (50% v/v). This study was extended by the same workers (Mortensen et al. 1997) to include five other carotenoids, with canthaxanthin (CAN) having the lowest rate constant of reaction with N02 (1.2 x 107 M 1 s-1), and LYC having the second highest (1.9 x 107 M 1 s-1) after ZEA (2.1 x 107 M 1 s-1). All the rate constants obtained were an order of magnitude below that for 3-CAR. However, the experiments were carried out in 60 40%, v/v tert-butanol/water mixture (80 20%, v/v for LYC due to aggregation) rather than the 50% (v/v) mixture used for 3-CAR and the N02" was generated in a different way. 

Alternatively, the process can be performed with K3Fe(CN)6 as the stoichiometric oxidant in tert-butanol/water mixtures [298]. In this case the olefin osmy-lation and osmium reoxidation steps are uncoupled, since they occur in different phases, resulting in improved enantioselectivities. However, from a practical point of view, the improved enantioselectivities (about 5-10% ee) are probably offset by the use of a less attractive oxidant. 

The catalytic cycle for the asymmetric dihydroxylation is shown in Figure 20. The reaction is carried out in a 1/1 t-butanol/water mixture to solubilize the potassium ferricyanide/potassium carbonate used as the oxidant. The solvent mixture, normally miscible, separates into two liquid phases upon addition of the inorganic reagents. 

No comparison exists for the standard potentials in terf-butanol-water mixtures or in anhydrous tert-butanol. However, the trends in the data obtained here in terf-butanol are similar to the trends observed in this work in ethanol-water and in anhydrous ethanol. See Figures 1 and 2 in which the standard potentials E° for the silver-silver bromide elec-... 

Figure 5. The pressure evolution of the critical consolute temperature in n-butanol - water mixture. The solid curve presents the parameterization via eq. (1) with basic parameters derived from the derivative based analysis via eq. (2), which results are shown in the inset.

The rapid decay of absorption of excited states on the ps time scale has been measured for pyrazolotriazole azomethine dyes. The molecular orientation dynamics of polar dye probes in t-butanol-water mixtures have been determined by ps fluorescence depolarization spectroscopy. Dyes studied in this investigation were the monocations nile blue and thionine, resorufin a monoanion, and nile red a polar but neutral molecule. A very detailed ps study of rotational diffusion of excited states of merocyanine-540 in polar solvents, has also been reported . 

UV-Photolysis of tert.-Butanol-Water Mixtures. Change from a Radical- to a Molecular-Fragmentation Process. In Vorbereitung. 

General procedure 2, copper metal-catalyzed synthesis of 1,2,3-triazoles [6, 23]. Phenylacetylene (2.04g, 20mmol) and 2,2-bis(azidomethyl)propane-l,3-diol (1.86g, lOmmol) were dissolved in 1 2 tert-butanol/water mixture (50mL). About 1 g of copper metal turnings was added, and the reaction mixture was stirred for 24 h, after which time TLC analysis indicated complete consumption of starting materials. Copper was removed, and the white product was filtered off, washed with water, and dried to yield 3.85 g (98%) of pure bis-triazole product. 

The Sharpless procedure for effecting osmium-catalyzed ligand-accelerated asymmetric dihydroxylation was utilized successfully the reaction could also be scaled up. Bis(3-methylthien-2-yl) ketone (59) was also a product in these reactions and was accompanied by an impurity whose structure has not been elucidated. Optimum yields of the dihydroxy material were obtained in dioxane-water/t-butanol-water mixtures. Use of osmium tetroxide instead of potassium osmate led to a slower reaction and increased the formation of undesired products. The material derived from synthesis revealed complete identity with the tablet degradates Any diastereomers that formed were not resolved under our chromatographic conditions. Attempted functionalization of the vicinal dihydroxy groups (acetate, acetonide, trflate) was unsuccessful and led to complex mixtures of products. 

Tommila and co-workers (155) found positive values of dEaldT for the alkaline hydrolysis of ethyl acetate in t-butanol-water mixtures. They ascribed this effect to a decrease of solvation of the transition state with increasing temperature. 

Hardy et al. [204] reported emulsion synthesis of yttrium aluminum garnet (commonly known as YAG) in which yttrium acetate and aluminum secondary butoxide (heated to 85 -90 C) were used as cation sources in a butanol-water mixture. The oil phase was heptane, mineral oil or Isopar, and the surfactant was a mixture of Span 20 (75%) and Span 80 (25%). The sol droplets were gelled by addition of NH4OH or bubbling NH3. The particle morphology and size were influenced significantly by the nature of the oil phase. 

In many cases, minced tissue is extracted with a buffer solution and then centrifuged. In some cases, membrane enzymes that are more firmly bovmd to the structural framework of mitochondria require special methods these include drying with acetone, treatment with butanol-water mixtures, extraction of dried mitochondria with various organic solvents, extraction using aqueous solutions of detergents, treatment with chaotropic ions, or exposure to the action of hydrolytic enzymes. 

Figure 3 DSC warming thermograms for tert-butanol/water mixtures (a) 15% w/w tert-butanol (b) 20% w/w tert-butanol (c) 50% w/w tert-butanol (Endotherm A melting of metastable eutectic Exotherm B recrystaUization of metastable eutectic form to stable form Endotherm C melting of eutectic Exotherm D melting of tert-butanol hydrate) (d) thermal treatment of 50% w/w solution at —TC to eliminate metastable states [28]. 

Amjad, M., Fletcher, D. and Smith, C.Z. (1977) The oxidation of benzyl alcohols and phenylethanols at Ni in alkaline f-butanol/water mixtures. Journal of the Electrochemical Society, 124, 203-208. 

Wakisaka, A., Mochizuki, S., and Kobara, H. (2004). Cluster formation of 1-butanol-water mixture leading to phase separation. J. Solution Chem., 33, 721-732. 

D. n-butanol-water (84 16) with 2 ml piperidine added to 98 ml of butanol-water mixture... 

F. Accascina, M. Battistini, and S. Schiavo, Scienza Tecnica, 5, 107 (1961). Conductance of lithium perchlorate in butanol-water mixtures. 

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