Hexafluoroacetone, hydration

Formed by fluorine oxidation of the dilithium salt of hexafluoroacetone hydrate, it is unstable and explosive. The chloropentafluoro homologue is similar. Proponents of their use as reagents claim that the dimethyl and methyltrifluoromethyl analogues are not explosive this seems improbable, especially since the less stressed lower dioxetanes (homodioxiranes) are all dangerous. 

Polyoxymethylene, obtained by the polymerization either of formaldehyde or of 1,3,5-trioxane,is a highly crystalline product which is insoluble in all solvents at room temperature with the exception of hexafluoroacetone hydrate at higher temperatures it dissolves in some polar solvents (e.g., at 130 °C in DMF or DMSO). If the unstable semi-acetal end groups are blocked (see Example 5-7) polyoxymethylene can be processed without decomposition as a thermoplastic at elevated temperatures in the presence of stabilizers. 

The magnitudes of two-bond carbon-fluorine couplings 2JCF in trifluoroacetic acid and hexafluoroacetone hydrate are 44 and 34 Hz, respectively (Table 3.14). Five-bond couplings of more than 20 Hz are reported for l,4,8-trimethyl-5-fluorophenanthrene derivatives their magnitudes decrease on saturation of the 9,10 bond in the phenanthrene... 

Yao, J.M., Masuda, H., Zhao, C.H., and Asakura, T. "Artificial spinning and characterization of silk fiber from Bombyx mori silk fibroin in hexafluoroacetone hydrate". Macromolecules 35(1), 6-9 (2002). 

Perfluorinated ketones form stable hydrates, (Rp)2C(OH)2, and these diols are very acidic. Hexafluoroacetone hydrate is known to be a very good solvent and is particularly useful for certain polymers [112, 152]. Perfluoropinacol may be obtained from hexafluoroacetone by photolytic reduction (Figure 8.44), whilst classical reduction with magnesium amalgam gives only low yields [112]. The same pinacol is also obtained by heating 8.44A, which is produced as shown in Figure 8.44 [153]. 

Abbreviations conform to Tarr s nomenclature F, formic acid A, acetic acid fA, trifluoroacetic acid KNm, dimethylformamide mSO, methylsulfoxide MOH, methanol EOH, ethanol MCN, acetonitrile M5KN, N-methyl-pyrrolidone 6N, pyridine N, ammonia ENm, dimethylethylamine M6N, N-methylpiperidine M6NO, N-methylmorpholine E6NO, N-ethylmorpholine ENip, diisopropylethylamine eN, triethylamine fmK, hexafluoroacetone (hydrate) cit, citric acid W, water NaA, sodium acetate eN+, tetraethylammonium MNT, methylthiocarbamyl NT, phenylthiocarbamyl MNGS, methylisothiocyanate ONCS, phenylisothiocyanate NPN-TNdab, N-aminopropyl-N -p-dimethylaminoazobenzene thiourea. 

In sterically hindered buffers such as hexafluoroacetone hydrate or pivalate in the presence of Zn, the hydride shift mechanism is completely dominant, and the second-order rate constant is proportional to [OD ], but in high concentrations of acetate the enolisation mechanism, with k hs = k3[Zn ][Base], becomes predominant. 

Based on its UV absorption, bis(trifluoromethyl)dioxirane (79) appears to have been generated by treatment of the mono- or dilithium salt of hexafluoroacetone hydrate (78) with elemental fluorine. ... 

Polyacetals are engineering plastics because of their high hardness, rigidity and tensile strength, good abrasion and wear resistance, and favorable low frictional properties, all of which are advantages over other materials. Since polyacetals absorb virtually no water, they have excellent weight retention characteristics. Polyacetals only dissolve in hexafluoroacetone hydrate at... 

Another group of solvents which are able to dissolve silk fibroin are fluorinated organic solvents like 1,1,1,3,3,3,-hexafluoroisopropanol (HFIP) (Lock, 1990 Trabbic and Yager, 1998 Liivak et al., 1998 Zhao et al., 2003) and hexafluoroacetone hydrate (Yao et al.,... 

Oxirans.— Epoxides are readily available from the catalytic oxidation of alkenes with 2-hydroperoxyhexafluoropropan-2-ol (HPHI) (1), which itself is easily prepared from hexafluoroacetone hydrate (2) and hydrogen peroxide (Scheme 1). HPHI is claimed to have similarities to the natural flavin hydroperoxides which are implicated in epoxidations and hydroxylations by external flavoprotein mono-oxygenases. Yields are typically in the range 77—92%. 

HEXAFLUOROACETONE HYDRATE 2584 60 ALKYLSULFONIC ACIDS, liquid with... 

Closely related to this, other olefins were tested in epoxidation reactions. The heterogeneous epoxidation of cyclooctene with H2O2 in scC02 using a manganese porphyrinate catalyst in the presence of hexafluoroacetone hydrate as the co-catalyst at 40" C and 200 bar, leads to complete transformation into cyclooctene oxide. The co-catalyst forms perhydrates and thereby helps to stabilise the porphyrine catalyst and to solubilise H2O2 in SCCO2. 

Monomer and polymer syntheses of PAI were performed as reported previously (9). Diacids with preformed imide groups were reacted with diamines to yield the PAI in one step (9-11). The diphenol 2,2-bis(4-hydroxyphenyl)hexafluoropropane for the PEI synthesis was obtained from Aldrich. The analogous diol with 4 methyl groups ortho to the hydroxy moiety (2,2-bis(3,5-dimethyl-4-hydroxyphenyl)hexafluoropropane) was synthesized by condensing hexafluoroacetone hydrate with 2 moles of 2,6-dimethylphenol following a patent (12). PEFs were obtained from diacids and diols in dry N,N-dimethylformamide (DMF)/pyridine (1/1) and an excess (2.6 mole/mole diacid) of tosyl chloride (13). Reaction time was 3 to 5 h at 120 °C under a dry argon flux. Reduced viscosities (0.5% at 30°C in N-methylpyrrolidone (NMP)) of > 0.35 dUg were required for the preparation of free-standing, non-brittle, methanol stable films. 

Hexafluoroacetone hydrate 25°C Hexafluoroacetone-water mixtures Hexafluoroacetone-sesquihydrate + triethylamine, 25°C Hexafluoroacetone-water (1 1.7 mol) -f triethylamine, 25°C p-Chlorophenol/2% a-pinene (60°C)... 

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