Haloaldehyde Polymers. VIII. Preparation and Polymerization of Dichlorofluoroacetaldehyde

Abstract

ABSTRACT:Dichlorofluoroacetaldehyde was prepared from methyl dichlorofluoroacetate by reduction with lithium aluminum hydride. Highly purified dichlorofluoroacetaldehyde was polymerized using various cationic and anionic initiators to a crystalline insoluble polymer or an amorphous soluble polymer, depending on polymerization conditions. It could be stabilized and the thermal degradation behavior was compared with polymers of other perhaloacetaldehydes. The monomer was also copolymerized with other haloacetaldehydes and phenyl isocyanate.KEY WORDS Dichlorofluoroacetaldehyde / Dichlorofluoroacetaldehyde Hydrate / Poly(dichlorofluoroacetaldehyde) / Copolymerization with Chloral / Cationic Polymerization / Anionic Polymerization Acetylation / End Capping / Polymer Degradation / Dichlorofluoroacetaldehyde polymerization was studied to learn more about the effects of molecular structure on the physical and chemical properties of perhaloacetaldehydes and their polymers; such as polymerizability, ceiling temperature, crystallinity, and thermal stability, in a series of perhaloacetaldehydes which have been investigated.Trichloroacetaldehyde, chloral, can be polymerized1-6 only to an infusible crystalline polymer insoluble in organic solvents. 1 · 2 Trifluoroacetaldehyde, fluoral, has been polymerized to crystalline 6 -8 or a mixture of crystalline and amorphous (presumably atactic) polyacetal depending on polymerization conditions. 9 This difference in polymerization is apparently caused by the smaller size of the fluorine atoms compared with the chlorine atoms. The crystalline forms of polychloral 2 and polyfluoral 8 are presumed to be isotactic polymers. Both polymers have been prepared with anionic and cationic initiators.It was concluded that in the polymerization * Part VII: B. Yamada, R.W. Campbell, and 0.Vogl, J. Polym. Sci. Chem. Ed., in press.

Tropospheric Reaction Products and Mechanisms of the Hydrochlorofluorocarbons 141b, 142b, 225ca, and 225cb

“…Further evaluations of the purities of the CFCl2CHO and CF2ClCHO preparations are presented in the Results and Discussion. The C=0 stretch frequency of gaseous CFCl2CHO was recorded at 1782.7 cm-1, and its NMR spectrum showed a doublet at h = 9.12 ppm with Jfh = 5.0 cps, in agreement with the data of Yamada et al (22). The ester CFC12C(0)0CH3 was obtained by heating a mixture of CC13C(0)0CH3 (Aldrich, 99%) and SbF3 (3:1 mole ratio; with a catalytic amount of Br2 added) and continuously distilling CFC12C-(D)OCH3 as it was formed.…”

Atmospheric Chemistry of CHF2CHO: Study of the IR and UV−Vis Absorption Cross Sections, Photolysis, and OH-, Cl-, and NO3-Initiated Oxidation

“…To our knowledge, two different ways of preparing CHF 2 CHO have been reported in the literature: reduction of CHF 2 C(O)OH 6 and preparation from a hemiacetal/hydrate mixture. 3,7 1-Ethoxy-2,2-difluoroethanol was prepared by a slight modification of a literature procedure. 8 A solution of ethyl difluoroacetate (2.01 g; 16.2 mmol) in 10 mL of dry ether was cooled to -85 °C.…”

Rate constants for the reactions of hydroxyl radicals and chlorine atoms with halogenated aldehydes

“…Dichlorofluoroacetaldehyde, chlorofluoroacetaldehyde, and difluoroacetaldehyde were prepared by treatment of the hemiacetal/hydrate mixtures. These compounds were obtained by reduction of the esters CC12-FCOOCH3, CHClFCOOC2H5 (Fluorochem), and CHF2-COOC2H5 (Fluorochem) by treatment with L1AIH4 at low temperature, according to the method of Yamada et al 12 The identity of dichlorofluoroacetaldehyde was confirmed by comparison of the infrared spectrum with that of Yamada et al 12 The ester, CCl2FCOOCH3, was prepared from CCI3COOCH3 (Aldrich) according to the method of Gryszkiewicz-Trochimowski et al,13 and the and 13C NMR spectra of the prepared ester were compared with those of Yamada et al12 All prepared samples were purified by repeated trap-to-trap distillation under vacuum and were analyzed by gas chromatography and infrared spectroscopy. Pure samples of these halogenated aldehydes rapidly undergo polymerization at room temperature and were therefore stored at 253 K in the dark.…”