Acetone, hexafluoro

Synonyms HFA acetone, hexafluoro per-fluoro-2-propanone perfluoroacetone 1,1,1, 3,3,3 -hexafluoro-2 -propanone... 

Acetone, hexafluoro. See 1,2-Epoxy-1,1,2,3,3,3-hexafluoropropane Acetone oils. See Acetone Acetone oxime... 

Trade Name Synonyms Cyracure UVR-6216 t[Dow http //www.dow.com] 1,2-Epoxy-1,1,2,3,3,3-hexafluoropropane CAS 428-59-1 EINECS/ELINCS 207-050-4 Synonyms Acetone, hexafluoro Hexafluoroepoxypropane Hexafluoro-1,2-epoxypropane Hexafluoropropene epoxide Hexafluoropropene oxide Hexafluoropropylene oxide Oxirane, trifluoro (trifluoromethyl)- Perfluoro (methyloxirane) Perfluoropropylene oxide Propane, 1,2-epoxy-1,1,2,3,3,3-hexafluoro-Propylene oxide hexafluoride ... 

In a related paper, reaction of(60a) with (56) gave the hydrospirophosphorane (61) which upon u.v. irradiation in the presence of dimethyl disulphide gave the methylthio derivative (62) which was also prepared by the reaction of(60b) with hexafluoroacetone1 2. In contrast, the reaction of (63) with hexafluoro-acetone furnished a 1 1 mixture of the 1,3,2-A3- and 1,3,4-A5-dioxaphospholanes (64) and (65). 

The radical-promoted reaction between polyethylene and hexafluoro-acetone is shown in Equation 1. It had been demonstrated previously in the case of simple hydrocarbons (8) that the addition of a carbon radical to the carbonyl group of hexafluoroacetone can take place in two modes, to yield the product, of substitution with either a fluoro-... 

Raw silk was dissolved in hexafluoro-iso-propanol (HFIP) [17, 33]. A typical working concentration for spinning was 2.5% (w/v) silk fibroin in HFIP. The spinning solution was pressed through a small needle (0 80-250 pm) into a precipitation bath (methanol for Bombyx mori silk proteins and acetone for Nephila clavipes silk proteins) and the silk solution immediately precipitated as a fiber. The best performing fibers approached the maximum strength measured for native fibers of Bombyx mori, but did not achieve the mechanical properties of natural spider silk. 

Chlorothionitrene complex, osmium, 37 262 Chloro(trifluoromethyl) peroxide, 16 144 Chlorotrimethylsilane, reaction with hexafluoro-acetone, 30 225... 

A flask was charged with hexafluoro-2,2-bis(3-amino-4-hydroxyphenyl)propane (0.8 mol), pyridine (1.6 mol), and /V- m e t h I - 2 - p rro I i d n e (1.2 kg) and then stirred at ambient temperature, cooled to — 25°C with a dry ice/acetone bath and treated with the dropwise addition of a solution consisting of isophthaloyl chloride (0.364 mol), 4,4 -oxy-bisbenzoyl chloride (0.364 mol), and /V- mcth I-2-pv rro I i done (700 g). The mixture was stirred at ambient temperature for 16 hours and then diluted with 2 liters of acetone and poured into 50 liters of deionized water. The precipitated white powder was recovered by filtration and washed with a mixture of deionized water and water/methanol, 1 1. The polymer was dried under vacuum at 40°C for 24 hours to obtain the product in quantitative yield having a Mw of 6400 Da with a poly-dispersity is 2.1. 

There are now several indications that the photolysis of hexafluoro-acetone is not as simple as it was originally supposed. Herzberg et al.,59 showed that the absorption spectrum of CF2 appeared under flash photolysis conditions and Kutschke60 has identified higher perfluoroalkanes in the normal photolysis, formed, it is supposed, by mechanisms analogous to those proposed for the 1,3-dichlorotetrafluoroacetone. The C F2 involved in all these reactions may arise from disproportionation reactions, possibly on the walls of the vessel, or may be produced in a molecular process from the ketone itself. 

The intermediate tertiary carbinol could not be detected (with the exception of bis(trifluoromethyl)(hydroxyphenyl)carbinol from hexafluoro-acetone and phenol [395]) and reacts readily with another molecule of phenol this second stage of the reaction is, in fact, an alkylation of phenol by the tertiary carbinol, or by the carbonium ion formed from it, by a common carbonium ion alkylation mechanism (Sect. 3.3). 

The quantum yield for decomposition of acetone from the triplet state is about 0.40 at 40°, and the quantum yield of phosphorescence is about 0.02.308 At least 407o of the initially excited molecules are not accounted for by either emission or chemical reaction, and thus must undergo some kind of radiationless decay to the ground state, presumably mostly from the triplet state. Recent studies of hexafluoro-acetone317 indicate that approximately half the triplet molecules formed by intersystem crossing undergo radiationless decay. 

F<, - acetone En—OTMs) 3,s-Dimethyl-4-oxo-l. 1.1 -trifluoro-2-trilluoromethyl- ElOh,. 448 (F, —acetone -r En —OTMs) 2-Propanole Hexafluoro-2-(4-... 

Propane 2-Diphenylphosphano-hexafluoro-2-trimethylxilyloxy-ElOb,. 683 (F6 — acetone +... 

Glucofuranose 5.6-0-(Hexafluoro-isopropylidene)-1,2-O-isopropyli-dene- ElOb,. 589 (5.6-Diol + F,-aceton)... 

HHFA hexafluoro acetyl acetone a quaternary amine... 

Pioneering work in fibroin wet spinning can be traced back to 1930s. After that, little work has been done until the late 1980s, when more research was done to investigate the spinning dope systems, and structure and properties of the artificial fibroin silk. The composition of the dope is very important to the properties of the final fiber. Several kinds of solvents, such as LiBr—EtOH, Ca(NOo,)2—MeOH, formic acid, HFIP, hexafluoro acetone (HFA), and so on, are used to prepare the spinning dope (Table 4). Very recently, an ionic liquid was used as dope solvent (Phillips et al., 2005). 

The salt is easily converted to the water-insoluble hexafluoro-phosphate. A filtered solution of 0.766 g. of the crude salt in 15 ml. of water is precipitated by slowly adding excess saturated aqueous ammonium hexafluorophosphate while the solution is stirred. The filtered solid is washed (50 ml. of water) until free of bromide ion and then washed with 30 ml. of anhydrous diethyl ether. Yield of the dried product is 0.973 g. (96%), m.p. 248-250°C. Recrystallization by letting a warm solution (20 ml. of 1 1 water-acetone) evaporate slowly gives no change in melting point. 

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