Nitrosyl chloride exhibits a number of different reaction modes in its reactions with monomeric and dimeric neutral carbonyl complexes of transition metals. From its reaction with [CpCr(CO)₃]₂ under controlled conditions, the organometallic compounds CpCr (CO)₂(NO) , CpCr(NO)₂Cl, [CpCrCl2]2, and [CpCr (NO) Cl₂]₂ can be obtained. In contrast.,, the analogous [CpM(CO)₃] ₂ (M — Mo or W) compounds react with C1N0 to produce CpM(CO)3Cl and CpM(NO)₂Cl in comparable yields. The (arene)M(CO)₃ (M = Mo or W) compounds form the polymeric [M(NO)2Cl2]n species via labile M (CO)₂(NO) 2Cl₂ intermediates under identical experimental conditions. Possible pathways leading to the formation of all products are presented. Trithiazyl trichloride, N₃S₃Cl₃, introduces the thionitrosyl group onto a metal centre during the reaction. Na[CpCr (CO)₃] + (1/3) N₃S₃3Cl₃ • CpCr (CO)₂(NS) An x-ray crystallographic analysis of this complex shows that the thionitrosyl group coordinates essentially linearly to the chromium via the nitrogen atom. A second product formed in this reaction, Cp₂Cr₂ (CO)₄S, possesses a novel Cr-S-Cr linkage which is linear, short, and chemically inert The cations, [(RC₅H₄)Mn(CO)₂(NO)] + (R = H or Me) react with I in acetone at room temperature to produce (RC₅H₄)Mn(CO)₂(NO)I. These species have very labile CO ligand which are readily displaced by Lewis bases to produce (RC₅H₄) - Mn(L) (NO)I [R = H, L = PPh₃ or P(OPh)₃; R = Me, L = PPh3, P(OPh)₃, or P(C₆H₁₁:L)₃]. The reactions of Br-, Cl⁻, and NO₂⁻ with [(RC₅H₄)Mn(CO)2(NO)]⁺ produce the unusual bimetallic compounds (RC₅H₄)₂Mn₂ (NO) ₃X (R == H or Me; X = Cl, Br, or N₂) The compound [CpCr(NO)2]2 abstracts all of the chlorine ligands from SnCl₄, MCl₂ (M = Hg, Sn, or Pb), CpFe-(CO)₂Cl, and Mn(CO)₅Cl in. refluxing thf to form CpCr(NO)₂Cl. The other products are the metals (M), [CpFe(CO)₂]₂, and Mn₂(CO)₁₀, respectively. The chromium dimer also abstracts halogen from vic-dihaloalkanes to produce the corresponding alkenes in good yields. / Science, Faculty of / Chemistry, Department of / Graduate

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published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

none

Thesis--Ph. D., University of Hong Kong. / Mimeographed.

Thesis--Ph. D., University of Hong Kong. / Typewritten.

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Polyvinyl Chloride (PVC), a plastic polymer composed of ∼43% hydrocarbon by weight and ~57% chlorine has become extensively used in our daily lives. However, the disposal of waste PVC plastics presents serious problems. The increased awareness of these problems requires the development of a reliable technique to dispose of these wastes in a safe and environmentally benign way that is devoid of the formation/release of organo-chlorine compounds. Chemical degradation of PVC is a technology that transforms PVC waste into completely new chemical products that don't contain chlorine. Sub-critical water (SCW) treatment is one of the most reliable technologies since SCW as a chemical reaction medium having adjustable physico-chemical properties. Hydrodechlorination (HDC), a reaction that replaces organically bound chlorine by hydrogen, can be accelerated by the presence of metal oxide catalysts (alumina supported palladium, Pd0/Al2O3) or raney nickel. When combined with SCW treatment, HDC offers a disposal process that is free from unwanted by-products. The rate of borohydride decomposition is accelerated by raney nickel. The HDC efficiency of virgin and formulated PVC in SCW under various reaction conditions of time and temperature was evaluated systematically. The time of reaction was varied from 1 to 4.5 hours and the temperature was varied from 150 to 280°C in the presence of palladium on alumina (Pd/Al2O3) or raney nickel. The efficiency of HDC varied from ~3% up to a completed dechlorination. Thus, organically bound chlorine in PVC in a water phase can be converted, virtually quantitatively, to chloride ion. / Response surface methodology (RSM) was used for experimental design and data analysis. The computer output from the Design-Expert software was used to optimize a model for the dechlorination as a function of time and temperature. A subsequent analysis of variance associated with the fitted model indicated a good fit between observed and predicted HDC efficiencies.