Academic literature on the topic 'FLUORINATED ALIPHATIC HYDROCARBONS'

Synthesis and properties of products based on tris[[tri(butoxy)titanate]boron with complete or partial substitution of butoxy groups linked with titanium by fluorinated alkoxy group were described. Extracted products were liquid or solid substances which are high soluble in aliphatic-, aromatic- chloraromatic- and chlorinated hydrocarbons, low alcohols, and ketone. Their structure was confirmed by elemental analysis, determination of molecular mass, IR and 1H NMR spectroscopy.

The reactivity of Ag(II)F2 towards a variety of organic compounds of a high degree of fluorination has been investigated. AgF2 readily fluorinates P(C6F5)3 to PF2(C6F5)3, and attacks the isothiocyanate functional group, -NCS, yielding Ag2S. Perfluorinated aliphatic nitriles resist the action of AgF2, but aromatic C6F5CN undergoes a radical-initiated oligomerization; byproducts include C6F6CN• and C6F5N2• (after intramolecular rearrangement following the bimolecular reaction). AgF2 oxidizes higher fluorosulfonic acids (C4F9SO3H, C8F17SO3H) at or close to the room temperature and triflic acid (CF3SO3H) at its boiling point to the corresponding peroxides. CF3COOH and CF3CONH2 are also decomposed in redox reactions, but the gaseous products have not been identified. Surprisingly, AgF2 is kinetically inert to perfluorinated aromatic hydrocarbons and to CCl4, but it decomposes CBr4 with vigorous elimination of Br2. CI4 decomposes explosively in the presence of AgF2. C6F5OH and CF3COOH are readily oxidized with AgF2 but, surprisingly, t-C4F9OH is kinetically resistant under similar conditions. Coordination complexes of perfluorinated aza and oxa Lewis bases (including perfluorinated 15-crown-5 ether) and AgF2 are not formed under the experimental conditions.

博士
國立臺灣科技大學
應用科技研究所
103
The control oxidation of aliphatic C-H bonds in regio- and/or stereo-selective manner by metalloenzymes is of great interest to scientists. Cytochrome P450 BM3 from Bacillus megaterium oxidizes C12-C20 fatty acids at the ω-1, ω-2, or ω-3 position of the C?{H bond, respectively. We employ the molecular manipulation techniques to overexpress the recombinant BM3 strain and carry out its site-directed mutagenesis study for generation of a variety of strains towards variable selective oxidation with different substrates. In my study, strain 3mt, A74G F87V L188Q is exploited for the controlled oxidations of medium-chain length alkanes. Single mutation variant, BM3 mutant Ala328Phe (F328), was found with its capability of selective oxidation at the ω?{1 position of C4-C10 straight-chain alkanes. Interestingly, long-chain fatty acids (C12-C20) are no longer its substrates. It provides a great base to allow us engineering P450 BM3 protein from normal alkanes with medium-chain length such as n-octane gradually to smaller alkane such as n-butane for subsequent studies of controlled oxidation. The introduction of the second mutation, at Leu188Pro (P450 BM3-FP188) can improve the catalytic efficiency from butane to 2-butanol for 12.5%. In addtion, introducinge Ala74Glu (P450 BM3-FPE74) can shrink the substrate pocket down to half of the volume and significantly enhance the catalytic activity of butane to 2- butanol for nearly 40%. Typically, enzymes invoke host–guest chemistry to sequester the substrates within the protein pockets, exploiting sizes, shapes and specific interactions such as hydrogen-bonding, electrostatic forces and/or van der Waals interactions to control the substrate specificity, regio-specificity and stereo-selectivity. To further investigate this issue, we also develope a series of deuterated and fluorinated aliphatic substrates as probes to gain insights into the controlled C-H oxidations of hydrocarbons facilitated by these enzymes. The effects resulting from the introduction of deuterated butane (isotopomers) and fluorinated octane (Bioisostere) substituents on the mechanistic insights for C-H oxidation and the controls for regio-specificity and stereo-selectivity of the C-H bond activation are discussed.