Methanol precipitant

The strongest known producer of j8-poly(L-malic acid) has been identified as Aureobasidium sp. providing 61 g of polymer from 1 liter of culture medium [5,6]. 8-Poly(L-malate, Ca -salt) of the culture broth was first separated from accompanying bulk pullulan by methanol precipitation. The water-redisolved precipitate was converted to the polymer acid by passage over Amberlite IR-120B (H -form). Thus, the best to-day producers of... 

The purification of j8-poly(L-malic acid) from A o-basiae has been reported involving methanol precipitation of the polymer in the form of the Ca salt [5]. This is possible because a high concentration of CaCOs is present in the growth medium. Unfortunately, the polymer acid is not soluble in aceton thus missing an additional purification step. In our hands, purification of jS-poly(L-malate) from several Aureobasidiae strains was unsatisfactory because of low yields and resisting impurities. 

FIGURE 7.17 Storage modulus and loss factor—temperature plots of the chameleon arhPIB-h-P(p-MeSt) block copolymer. = precipitated into methanol, = precipitated into acetone. (From Puskas, J.E., Dos Santos, L., and Kaszas, G., J. Polym. Set Chem. A., 44, 6494, 2006. With permission.)... 

Two types of networks were prepared (i) randomly crosslinked polybutadiene, and (ii) model urethane networks, (a) polybutadiene based, and (b) poly(e-caprolactone) based. The randomly crosslinked networks were prepared from polybutadiene (Duragen 1203 obtained from General Tire and Rubber Co.) crosslinked with di-cumyl peroxide. Specifications of the as obtained polybutadiene are given in Table I. Polybutadiene was purified by dissolving in benzene and precipitating in methanol. Precipitated polybutadiene was redissolved in benzene. Seven different weights of dicumyl... 

Analyses of the products of several typical reactions after isolation by methanol precipitation are presented in Table I. 

Fpooedme B. Nine grams (dry basis) of ethanol- precipitated and edr-dried graft ocpolymer was mixed with 81 inL of 0.7N sodium hydroxide in a 250-mL Erlenmeyer flask. The flask was heated on a steam bath for 10 min, loosely stoppered, and placed in a 100 C oven for either 1.5 or 3 h. Only about 1 g of volatile material was lost during heating. Ihe cooled reaction mass was methanol-precipitated as described in Procedure A. 

The influence of methanol precipitation conditions on water absorbencies of final products is lown in Ted le I, and results of this stuc may be sunnarized as follows 1) If the se xxiificate is stirred for 1 h open to the atmo here to allow some of the anmonia to esce before methanol precipitation, the polymer has about the... 

Allowing the saqponificate to age in a covered beaker for 6 days at rocm temperature before methanol precipitation does not adversely affect and may even improve absorbency. 3) Increasing the amount of methanol used in the initial precipitation from 300 to 500 mL per 100 g of saponif icate does not greatly change the absorbency of the firal product. 

After alkaline saponification, each reaction mixture was divided into three portions %bich were treated as follows 1) Absorbent polymer was methanol-precipitated as is with no adumiium chloride treatment. These products served as controls and provided absorbency vadues that could be conpared with absorbencies presented in earlier tables. 2) Absorbent polymer was methanol-precipitated aifter addition of either 15, 12.5, or 10 g of AlCls 6H20 to the saponiflcate. 3) Polymer was methanol precipitated after adding aduminum chloride followed by an amount of s um hydroxide solution equivalent to that needed to convert alumirum chloride to aduminum hydroxide. Wicking as well as absorbency was then determined both as is and aifter treatment with HCl in methanol to neutralize excess alkali. 

Preliminary estimates for full-scale treatment costs of uranium-contaminated soils were developed based on laboratory-scale studies. The process design uses polyethylene glycol (PEG) (15% solution) and sodium carbonate (10% salt solution) for the aqueous biphasic extractiou system. Uranium is recovered from the salt-rich phase by methanol precipitation. Methanol is then recovered by distillation. 

The most expensive operation of the process is the secondary treatment of the salt-rich phase involving methanol precipitation/distillation (D13753L, p. 2). Further research on alternative methods for the removal of dissolved uranium from concentrated sodium carbonate are underway. 

Indyk and Woollard (195) demonstrated that the removal of cholesterol from the un-saponifiable fraction of vitamin D-supplemented whole milk powder by methanolic precipitation and filtration was an adequate cleanup procedure, making semipreparative HPLC unnecessary. This simplified procedure was made possible by connecting two analytical columns in series. The tandem columns adequately separated vitamins D2 and D3 from one another and from vitamins A and E. The analysis of infant formulas (100) required cleanup by silica solid-phase extraction to remove the minor tocopherols and tocotrienols, which constituted potential sources of interference. 

When butadiene was polymerized in the presence of a PVC suspension in chlorobenzene using a catalyst system based on Et2AlCl, the methanol-precipitated reaction product had little or no solubility in refluxing hexane. The soluble fraction, when obtainable, was identifiable as a greater than 90% cw-1,4-polybutadiene. In this case, the hexane-insoluble residue was essentially completely soluble in tetrahydrofuran, probably owing to the low molecular weight of the polybutadiene in the PVC-cw-1,4-polybutadiene reaction product. 

Figure 18 Effect of nonionic detergent (Triton X-100) on benzydamine N-oxygenation (FMO) and N-demethylation (CYP) by human liver microsomes. Benzydamine (500 pM) was incubated with pooled human liver microsomes (1.0 mg protein/mL) in tricine buffer (50 mM, pH 8.5 at 37°C) with or without Triton X-100 [1% (v/v)]. Reactions were initiated by the addition of an NADPH-generating system and stopped after 10 minute by the addition of an equal volume (500 pL) of methanol. Precipitated protein was removed by centrifugation, and an aliquot (25 pL) of the supernatant fraction was analyzed by HPLC with fluorescence detection. Abbreviations FMO, flavin monooxygenase CYP, cytochrome P450.

Methacrylic Acid Content in Polymer. One gram of methanol-precipitated, water-washed, dried polymer was dissolved in 100 ml. tetra-hydrofuran (THF) and titrated to a faint pink phenolphthalein end point with 0.055 n-benzyltrimethylammonium hydroxide in THF. The base was standardized by potentiometric titration against 0.01N acetic acid in methanol. The value for a non-acid containing polymer of the same series was used as a blank. All analyses were within 5% of the theoretical value. 

The effect of introduction of regularly disposed cyclic fragments into the macromolecular backbone on conformational and hydrodynamic parameters is also studied [30], For this purpose, copolymers 3 and 4 (Table 1) were fractionated into twelve fractions from the benzene (solvent) - methanol (precipitator) system. The influence of cyclic groups, introduced into the polymer backbone, on rigi-dity parameters was determined by direct computer simulation of macromolecular coil with the help of the Monte-Carlo method. 

In the first, Fe(CO)5 and distilled methylacrylate were sonicated as a mixture of neat liquids. During the sonication, the glass cell was wrapped in a dark cover to avoid photopolymerization. After 30 min of irradiation (avoiding degradation) at a dry ice-acetone temperature, the solution was treated with cold methanol, precipitating the polymeric product. In the second method, amorphous iron nanoparticles were prepared following Suslick s recipe [6]. The dried amorphous iron powder was introduced into the sonication cell without exposure to air and mixed with a solution of the methylacrylate monomer in N,N -dimethylformamide (DMF). The concentration of the methylacrylate solution in DMF was 5.5 M. 35 ml of this solution was mixed with various amounts of amorphous iron nanoparticles. The amounts of the iron powder were changed from 50 mg to 200 mg. The chemical analysis of polymers prepared by the two methods is presented in Table 6.1. 

PIO. Pillemer, L., and Hutchinson, M. C., The determination of the albumin and obulin contents of human serum by methanol precipitation. J. Biol. Chem. 168, 299-301 (1945). 

A third method was tried that gave undesirable results. The initiator and monomer were dissolved in tetrahydrofuran, a common solvent. In attempting to strip off the THF in a roto-vac at room temperature, it was found that polymerization of the BA-DAB-BA was initiated and advanced, even while there was still retained solvent. Since these factors contribute to processing difficulties and undesirable porosity in cured specimens, this method was discarded, and the methanol precipitation method was selected. 

Approximately 60 grams of BA-DAB-BA was synthesized using the Hedberg procedure.(1) One-half of this material was evaluated in its pure form, while the other half was first blended to 1% concentration with the initiator using the methanol precipitation method, and then evaluated. Both samples were subjected to DSC scans at 20°C/min. The results are shown in Figure 1. 

The first step in this investigation was to isolate the pigment from strawberry juice by the method described by Sondheimer and Kertesz (11). This method involved the saturation of the juice with salt and extraction with 1-butanol, then concentration of the butanol extract under vacuum and in a nitrogen atmosphere. The anthocyanin concentrate was then taken up with hydrochloric acid in anhydrous methanol, precipitated with ether, dissolved in 0.01% hydrochloric acid, and saturated with picric acid. The anthocyanin picrate crystallized out of this solution upon storage at 0° C. as lustrous reddish bronze prisms which were further purified by recrystallization. 

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