Isobutyl MPA

TABLE 7.3. Characteristics of the procedures for determination of O-isobutyl MPA as a marker of exposure to RVX, in urine and blood plasma... 

FIGURE 7.2. Concentration of O-isobutyl MPA in blood plasma versus time after intramuscular injection of RVX in rats at a dose of 0.8 x LD50. 

In this chapter, we presented the principal products of RVX hydrolysis with excess water in an acid medium. It has been shown that after the 3 months exposure, close to 1% of the initial amount of RVX in the solution could be detected. According to data on RVX hydrolysis with an equimolar amount of water, the autocatalytic hydrolysis of RVX was almost completed after 3 months, since the RVX content in the sample was no more than 0.01%. Moreover, the reaction mixture was much poorer than in the case of hydrolysis with excess water. Isobutyl MPA, which catalyzes RVX degradation, was detected as the major component of the reaction mixture. Yang et al (1996) found 2-(diethyl amino)ethanethiol as the second major component of the mixture, but in our experiment it was almost completely converted into bis[2-(diethylamino)ethyl]disulfide. 

Procedures for identification and quantitative assessment of O-isobutyl MPA (a marker of exposure to RVX) in urine and blood plasma have been developed, and toxicokinetic experiments conducted to measure O-alkyl MPA in rat plasma after intramuscular injection of RVX at a dose of 0.8 X LD50. In addition, we have obtained a mass spectrum of human albumin after in vitro incubation of blood serum with RVX. Incubation of commercially available human albumin with RVX with subsequent trypsinolysis and MS/ MS analysis has revealed two sites of binding RVX to human albumin, Tyr 411 and Tyr 150. These data could contribute to development of sensitive and specific diagnostic methods. 

TABLE 10.3 Characteristics of the Procedures for Determination of O-isobutyl MPA as a Marker of Exposure to RVX, in Urine and Blood Plasma... 

German vinyl ether plants were described in detail at the end of World War II and variations of these processes are stiU in use. Vinylation of alcohols from methyl to butyl was carried out under pressure typically 2—2.3 MPa (20—22 atm) and 160—165°C for methyl, and 0.4—0.5 MPa (4—5 atm) and 150—155°C for isobutyl. An unpacked tower, operating continuously, produced about 300 t/month, with yields of 90—95% (247). 

Acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, ethyl acetate, and tetrahydrofuran are solvents for vinyhdene chloride polymers used in lacquer coatings methyl ethyl ketone and tetrahydrofuran are most extensively employed. Toluene is used as a diluent for either. Lacquers prepared at 10—20 wt % polymer sohds in a solvent blend of two parts ketone and one part toluene have a viscosity of 20—1000 mPa-s (=cP). Lacquers can be prepared from polymers of very high vinyhdene chloride content in tetrahydrofuran—toluene mixtures and stored at room temperature. Methyl ethyl ketone lacquers must be prepared and maintained at 60—70°C or the lacquer forms a sohd gel. It is critical in the manufacture of polymers for a lacquer apphcation to maintain a fairly narrow compositional distribution in the polymer to achieve good dissolution properties. 

The principal commercial source of 1-butanol is -butyraldehyde [123-72-8] obtained from the Oxo reaction of propylene. A mixture of n- and isobutyraldehyde [78-84-2] is obtained in this process this mixture is either separated initially and the individual aldehyde isomers hydrogenated, or the mixture of isomeric aldehydes is hydrogenated direcdy and the n- and isobutyl alcohol product mix separated by distillation. Typically, the hydrogenation is carried out in the vapor phase over a heterogeneous catalyst. For example, passing a mixture of n- and isobutyraldehyde with 60 40 H2 N2 over a CuO—ZnO—NiO catalyst at 25—196°C and 0.7 MPa proceeds in 99.95% efficiency to the corresponding alcohols at 98.6% conversion (7,8) (see Butyraldehydes Oxo process). 

Hypalon CP 826. This is a chloriaated, maleic anhydride modified polypropylene having a chlorine content of about 25% and maleic anhydride content of about 0.8%, developed to promote adhesion of inks and coatiags to polypropyleae or bleads containing polypropyleae. It has a solutioa viscosity of 125 mPas(= cP) at 20% soHds ia xyleae and can be used ia dilute solutioas as a wash primer or a tie layer betweea materials that are difficult to adhere. CP 827 is a higher molecular-weight analogue with a solution viscosity of 280 mPas(= cP) at 20% soHds ia 80/20 xylene/methyl isobutyl ketoae. 

The determination of phosphorus after precipitation and solvent extraction as molybdophos-phoric acid (MPA) and reduction to molybdenum blue is a classical procedure,30 40 while cerium can be determined directly as molybdocerophosphoric acid (MCPA emax 7300 at 318 nm). A more selective method is to strip excess of MPA by extraction with chloroform, then to decompose residual MCPA and determine the phosphate liberated therefrom as MPA after extraction into isobutyl acetate. Alternatively AAS can be used to determine the amount of molybdenum. 

The reductive alkylation of /V-alkylarylamines and diarylamine with ketones to give tertiary amines has been investigated by Greenfield and Malz, Jr.42 with platinum metal sulfides that had been shown to be excellent catalysts for the reductive alkylation of primary arylamines with ketones37 (see eq. 6.15). Good conversions to tertiary amines were obtained with relatively unhindered secondary arylamines and less hindered ketones. The relative ease in the reductive alkylation of diarylamines with ketones was in the following order cyclohexanone > acetone > ethyl methyl ketone > isoamyl methyl ketone > isobutyl methyl ketone. For example, 58% of diphenylamine was converted to iV-alkyldiphenylamine with cyclohexanone over rhodium sulfide at 150°C and 3.4-5.5 MPa H2 (eq. 6.19), while with isobutyl methyl ketone, a conversion of only 28% was obtained even at 235°C with in the same reaction time. 

Based on the palladium-catalyzed carbonylation of l-(4-isobutylphenyl)etha-nol, which is produced via salt-free acylation of isobutylbenzene to 4-isobutyl-acetophenone and subsequent hydrogenation, the former Hoechst Celanese Corporation [33] developed an ecologically superior process to produce ibuprofen in a plant operating since 1992 on a 3500-ton scale (eq. (9) 1 bar = 0.1 MPa) [34]. 

In contrast to supercritical drying, operating parameters for subcritical drying including temperature and pressnre are below the critical point. Wei et al. [35] nsed E-40 (multi-polysiloxane) as silicon source and isobutyl alcohol as solvent to prepare Si02 gel. The prepared gel was placed in autoclave, adding an appropriate amonnt of isobutyl and surfactant, preserved sometime under pressure of 2.3-2.6 MPa, temperature of 240°C-260°C, and then deflated slowly and cooled naturally hydrophobic SiOj aerogel was finally obtained. 

Chem. Desalp. Isobutyl methacrylate CAS 97-86-9 EINECS/ELINCS 202-613-0 Uses Used in leather, lacquer, paper, and textile industries base material for coatings, adhesives oil additives dental prods. floor care prods. toner resins polymerization and copolymerization in emulsion and sol n. Properties Pt-Co 5 max. clear Ikr. ester-like odor sol. 0.5% water in ester, 0.2% ester in water (20 C) m.w. 142.2 sp.gr. 0.888 vise. 0.9 mPa s (20 C) vapor pressure 4 mbar (20 C) b.p. 155 C solid, pt. -37 C flash pt. 45.5 C ref. index 1.420 99.5% min. purity 0.005% max. acid 0.02% max. water Toxicology TSCA listed... 

Cyanoacrylates were shown to form a strong durable bond between bones in vitro. Tensile adhesive strength betw een smooth bovine cortical bone specimens bonded together with the isobutyl monomer and tested after one day storage in water was approximately 6.5 mPa (Brauer et al, 1979). The monomer was used, without evidence of histotoxicity, to repair osteochondral fractures (Harper and Ralston, 1983) and recently to improve meniscal repairs (Koukabis et al, 1995). Butylcyanoacrylate was also used in facial bone surgery for frontal bone reconstitution (Avery and Ord, 1982). 

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