Epoxy compounds analysis

Another example of interest with regard to the reaction mechanism is the analysis of epoxy groups. Durbetaki60 titrated a-epoxy compounds with HBr (cf., p. 260) in glacial acetic acid with crystal violet as indicator, but the method was slow for glycidyl esters, CH2—CHCH2OOCR. As it concerns a two-step... 

On a capillary GC analysis, the separation of positional isomers of epoxy compounds is generally well accomplished by a high polar column, such as DB-23, rather than by a low polar column, such as DB-1. For the positional isomers, a different elution order depending on the kinds of column has not been reported. In the case of two mono epoxides derived from Z6,Z9-dienes, 6,7-epoxides elute slightly faster than 9,10-epoxides [72,170],but the separation is insufficient even on the high polar column. Three monoepoxides derived from Z3,Z6,Z9-trienes elute in the order of 6,7-, 3,4-, and 9,10-epoxides [9]. The former two isomers are sufficiently separated on the high polar column, while the elution of the latter two isomers overlaps [71]. For each positional isomer of diepoxides derived from the Z3,Z6,Z9-trienes, two diastereomeric... 

See also Epoxy coatings Epoxy chalcone, 10 450 12,13-Epoxy-cis-9-octadecenoic (vernolic) acid, physical properties, 5 35t Epoxy coatings, 10 436 450 17 845. See also Epoxy can coatings for corrosion protection, 7 199 markets for, 10 442-449 performance of, 10 423 waterborne, 10 439 Epoxy composites, 10 450, 451 Epoxy compounds, photoinitiated polymerization of, 23 716 Epoxy content analysis, 10 385 Epoxy cresol novolac (ECN) resins, 10 367, 369... 

The enantiomeric excess was determined by HPLC analysis (column Daicel Chiralcel OD-H, eluent n-hexane/2-propanol 98/2, flow rate 0.5 mL min, detector UV 254 nm, retention time 32.4 and 34.3 min). Absolute configuration of the epoxy compound was (xR,pS), which was determined by comparison of HPLC data with the literature reference. " ... 

The cationic polymerization mechanisms by which these initiators (Table 1) work were examined only in few cases. Such investigations were based on the polymerization of monoepoxides and on the analysis of the intermediate and fmal reaction products. However, the results can clarify crosslinking of technical epoxy resins only to a certain extent. It has to be taken into account that these resins are sold only in a commercial de, they all contain small amounts of by-products, catalysts etc. which can influence and alter the mechanisms as established with low-molecular epoxy compounds Nevertheless, these commonly available epoxies are useful as technical working materials. 

Chemical analysis of an insulator from one supplier indicated polymer fragments and curing byproducts, as shown in Figure 10-13. In contrast, an analysis of an insulator from another supplier indicated significant differences. In the second case, traces of polymer fragments were found in addition to thorough crosslinking of the epoxy compound. 

The specific gravity of epoxy compounds ranges from 1.10 to 2.10. It bums with a yellow flame and gives off a black smoke that gives off a pungent amine odor. Different types of epoxies can be characterized by infrared spectroscopy and thermal analysis. 

Aromatic amines formed from the reduction of azo colorants in toy products were analysed by means of HPLC-PDA [703], Drews et al. [704] have applied HPLC/ELSD and UV/VIS detection for quantifying SFE and ASE extracts of butyl stearate finish on various commercial yarns. From the calibrated ELSD response the total extract (finish and polyester trimer) is obtained and from the UV/VIS response the trimer only. Representative SFE-ELSD/UV finish analysis data compare satisfactorily to their corresponding SFE gravimetric weight recovery results. GC, HPLC and SEC are also used for characterisation of low-MW compounds (e.g. curing agents, plasticisers, by-products of curing reactions) in epoxy resin adhesives. 

Z = 4 D, = 1.52 R = 0.049 for 1,606 intensities. An error in the atomic coordinates for C-6 prevents display of this molecule. The atomic coordinates for C-l 1 were omitted, and those for H-61 and H-62 appear to be in error. The linkage, orientational angles between the hexenopyranosyl and the pyranoside ring are 0-5 -C-l -0-4-C-4 = +83°, C-l -0-4-C-4-C-5 = —139°. The epoxy ring is equilateral, with C-C = C-0 = 146 pm, and the ring-angles equal to 60 0.3°. The results of this analysis were correlated with those from the n.m.r. spectrum of the compound in solution. 

Bromide analysis, of water, 26 41 Bromide ions, in development solution, 79 205-206 Bromides, 4 319-330 thorium, 24 763 titanium, 25 54 tungsten, 25 379 uranium, 25 439 Bromimide, 4 299, 319 Brominated additive flame retardants, 77 461-468, 471-473t Brominated Anthanthrone Orange, pigment for plastics, 7 367t Brominated aromatic compounds, 7 7 459 Brominated bisphenol A-based epoxy resins, 70 366... 

A new elegant stereoselective synthesis of humulene (192) has been achieved by a route (Scheme 22) in which the 11-membered-ring framework [cf. (191)] is produced by cyclization of the 11-allylpalladium complex derived from intermediate (190). Buddledin-A (193), -B (194), and -C (195) are new piscicidal sesquiterpenoids which have recently been isolated from the root bark of Buddleja davidiC The caryophyliane framework of these compounds has been established by spectroscopic data and X-ray analysis of the mono-bromohydrin (196) derived from buddledin A (193). An extension of previous studies on the cyclization of the epoxy-ketone (197) derived from caryophyllene has shown that the base-catalysed cyclization of the isomeric epoxy-ketones (198) and (199) provides compounds... 

The relevant properties of these materials for the torsional-mechanical analysis are listed in Table 8.11. On the basis of specific elastic modulus and specific shear modulus, the best materials are the graphite-fiber-reinforced epoxy resin, followed by either of the alloys, then the Kevlar fiber-reinforced epoxy. The chopped glass sheet molding compound is obviously not a good choice. 

The biotransformation of linalool by Botrytis cinerea has also been described [60]. After addition of linalool to botrytised must, a series of transformation products was identified (E)- (49) and (Z)-2,6-dimethyl-2,7-octadiene-l,6-diol (48), trans- (76) and cw-furanoid linalool oxide (77), trans- (78) and c/s-pyranoid linalool oxide (79) and their acetates (80, 81), 3,9-epoxy-p-menth-1 -ene (75) and 2-methyl-2-vinyltetrahydrofuran-5-one (66) (unsaturated lactone), Fig. (11). Quantitative analysis however, showed that linalool was predominantly (> 90%) metabolised to ( )-2,6-dimethyl-2,7-octadiene-l,6-diol (49) by B. cinerea. The other compounds were only found as by-products in minor concentrations. 

Epoxy is used as a lining for water reservoirs, water mains, and home plumbing systems (Heim and Dietrich, 2007a). These applications can impact sensory quality of tap water in food manufacturing, food service operations, and residential homes. This effect may be most noticeable in water but residual aroma and flavor compounds may cause a taint in foods prepared with these water sources. An odor assessment, using a water industry standard flavor profile analysis method, identified a strong relationship between water (simulated tap water, pH 7.7-7.9) stored in epoxy-lined copper pipes for 3-4 days and an odor described... 

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