Acetates, properties/recovery

Coran and Patel [33] selected a series of TPEs based on different rubbers and thermoplastics. Three types of rubbers EPDM, ethylene vinyl acetate (EVA), and nitrile (NBR) were selected and the plastics include PP, PS, styrene acrylonitrile (SAN), and PA. It was shown that the ultimate mechanical properties such as stress at break, elongation, and the elastic recovery of these dynamically cured blends increased with the similarity of the rubber and plastic in respect to the critical surface tension for wetting and with the crystallinity of the plastic phase. Critical chain length of the rubber molecule, crystallinity of the hard phase (plastic), and the surface energy are a few of the parameters used in the analysis. Better results are obtained with a crystalline plastic material when the entanglement molecular length of the... 

This product was 88% pure based on recovery of an analytical sample from chromatography on silica gel 60 eluted with 30% ethyl acetate/hexanes. Physical properties and spectral data are as follows ... 

The overwhelming conclusion supported by data is the superiority of the FT-30 composite membrane for the majority of organic compounds tested. From arguments presented earlier, improved recovery of organic compounds on the basis of these higher rejection properties would be expected. Data from selected literature sources (6, 10-20) on membrane rejections of organics in water at parts-per-million levels were reviewed. Results are presented by chemical class in Table VI. Data are compiled for cellulose acetate and a cross-linked NS-1-type composite membrane. Differences in the rejection of various compound classes by the two membrane types determined at higher solute levels are similar to those observed and reported here at parts-per-billion levels. 

During a synthesis of the Chlorothricolide, Roush and Sciotti encountered unexpected problems with the hydrolysis of the dimethyl acetal 54.1 [Scheme 2.54].112 Use of some of the standard hydrolysis conditions (oxalic acid, PPTS, PTSA, HO Ac, or trifluoroacetic acid — all in acetone) resulted in recovery of 54.1 or decomposition. Success was achieved by exploiting the mild Lewis acidic properties of the lithium cation under conditions first reported by Lipshutz and Harvey.113 Thus treatment of the dimethyl acetal 54,1 with lithium tetrafluoroborate in acetonitrile containing 2% water returned the desired aldehyde 54J in 97% yield after 2 h at room temperature. The reaction was also applied to the deprotection of a cyclic ketal in a synthesis of Pumi-liotoxin.114 115... 

The nonyl aldehyde coproduct of the azelaic half aldehyde is a useful intermediate after being transformed into the corresponding alcohol, acid, or amine, it is a raw material for plastics. Several years ago, I. Sakurada, Kyoto University, the inventor of Vinylon, found that when nonyl aldehyde is used instead of formalin for acetalization of poly (vinyl alcohol), the properties of Vinylon yarns are considerably improved, especially in elastic recovery. 

There have been many efforts to commercialize 2,6-dicarboxynaphthalene for the preparation of poly(ethylene-2,6-naphthalate) due to its favorable thermoplastic properties compared with PET. Therefore, there are numerous patents in which 2,6-alkyl-substituted (alkyl = methyl, ethyl, isopropyl) naphthalenes are oxidized to the corresponding aromatic di-acids, applying mostly Co/Mn/Br catalysts with various co-catalysts such as Zr or Pd in acetic acid as the solvent. The major byproduct is formed by the oxidation of the naphthalene ring to give trimellitic acid (TMA) [5a, 8]. Sumikin Chemical has developed a method to prepare 2,6-naphtha-lenedicarboxylic acid by oxidation of 2,6-diisopropylnaphthalene (2,6-DIPN) in the liquid phase with air in a 500 tpy plant. Sumikin uses a newly developed catalyst based on Co/Mn with an addition of a few ppm of Pd giving advantages such as yields higher than 90 %, suppression of TMA production to around 1 %, and thus better catalyst recovery, and reduced consumption of acetic acid. 

The first criterion was to identify a crystalline diastereomeric salt of oxazinone ( )-l. Many chiral acids were screened and [(LS)-(endo,anti)]-(-)-3-bromocamphor-8-sulphonic acid (BCSA) afforded a 27% yield of the diastereomeric enriched (88% de) BCSA salt (Scheme 5). This was upgraded to 99% de with an 88% recovery after recrystallization from DMF//5o-propyl acetate (IPAC). A necessary physical property of... 

Aluminum chloride hydrate is used in textile finishing to impart crease recovery and nonyeUowing properties to cotton (qv) fabrics, antistatic characteristics to polyester, polymide, and acrylic fabrics, and to improve the flammability rating of nylon (see Textiles). Dye-bleeding of printed textile may be blocked (17) by treatment with aluminum chloride and zinc acetate, Zn(02CCH2)2j followed by solubilizing with ethylenediamine tetraacetic acid, and washing from the fabric. 

The relationship between adsorption and interfacial properties such as contact angle, zeta-potential and flotation recovery is illustrated in Figure 39.2 for cationic surfactant dodecylammonium acetate/quartz system (5). The increase in adsorption due to association of surfactants adsorbed at the solid-liquid interface into two dimensional aggregates called solloids (surface colloids) or hemi-micelles occurs at about 10 M DA A. This marked increase in adsorption density is accompanied by concomitant sharp changes in contact angle, zeta-potential and flotation recovery. Thus these interfacial phenomena depend primarily on the adsorption of the surfactant at the solid-liquid interface. The surface phenomena that reflect the conditions at the solid-liquid interface (adsorption density and zeta-potential) can in many cases be correlated directly with the phenomena that reflect the... 

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