Unsaturated Compounds In Presence Research Articles

Kinetics and Mechanism of Bromine Addition to Derivatives of Unsaturated Aliphatic Carboxylic Acids in Aqueous Solution

Abstract This paper deals with the kinetics of bromine addition to unsaturated compounds in presence of added bromide ions at 22, 30, 38, 46, and 54 °C. The substrates used were acrylamide (AAm), methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), t-butyl acrylate (tBA), methacrylamide (MAAm), methyl methacrylate (MMA), ethyl methacrylate (EMA), methyl crotonate (MC), and ethyl crotonate (EC). The kinetics was followed potentiometrically. The activation parameters (ΔH\eweq, ΔS\eweq, and ΔG\eweq) were calculated and compared. Estimation of product ratio of bromohydrin to dibromide showed the absence of any correlation of the product formation with reactivity of the substrates. The observed parameters are discussed in relation to the proposed reaction mechanisms.

Reaction of gem-trichloroalkanes with unsaturated compounds in presence of Fe(CO)5 and a cocatalyst

The following reactions were effected in the presence of the coordination initiators Fe(CO)5 + i-C3H7OH (or Hexametapol): a) Telomerization of vinyl chloride with 1,1,1-trichloropropane and 1,1,1,3,3-pentachloropropane. Telomers that contain 1–3 monomeric units in the molecule were isolated, b) The addition of 1,1,1,3-tetrachloropropane and 1,1,1-trichloroethane to isobutylene; the adducts were obtained in good yields, c) The reaction of allyl chloride with 1,1,1,3-tetrachloropropane, which leads to the formation of the adduct and by-products as the result of the partial fragmentation of the ClCH2CH2CCl2CH2CHCH2Cl radicals with the cleavage of chlorine atom.

Addition of arylfluorosilanes containing silicon-attached hydrogen

1. In additions to unsaturated compounds in presence of a H2PtCl6 catalyst, hydride arylfluorosilanes are considerably more reactive than their chloro analogs. 2. The arylfluorosilyl groups of difluorophenylsilane and difluoro-1-naphthylsilane add at both of the carbon atoms of the vinyl group of styrene (mainly at the α-carbon atom), whereas the dichlorophenylsilyl group of dichlorophenylsilane adds only, to the end carbon atom of the double bond. The fluorodiphenylsilyl group of fluorodiphenylsilane adds to almost equal extents at both carbon atoms of the vinyl group of styrene. 3. In high-temperature condensation with chlorobenzene the replacement of the chlorine atoms of dichlorophenylsilane by fluorine atoms leads to a reduction in the ratio of condensation and reduction products.

Reactions of carbon tetrachloride with unsaturated compounds in presence of dicyclohexyl peroxydicarbonate or oxidation-reduction systems

1. The oxidation-reduction system benzoyl peroxide-dimethylaniline initiates the addition of carbon tetrachloride to alkyl vinyl ethers and the telomerization of allyl acetate with carbon tetrachloride at 25–30dg. 2. The oxidation-reduction system benzoyl peroxide-(p-tolylsulfonyl)methanol-iron triacetylacetonate initiates the telomerization of allyl acetate with carbon tetrachloride at 30–32dg. 3. Dicyclohexyl peroxydicarbonate initiates the addition of carbon tetrachloride to butyl vinyl ether at 30° and the telomerization of allyl acetate, allyl chloride, and 1-octene with carbon tetrachloride at 55–60dg.

Addition of silicon hydrides to unsaturated compounds in presence of nickel carbonyl

1. Nickel tetracarbonyl catalyzes the cyanoethylation of dichloromethylsilane and triethylsilane and also the addition of triethylsilane to acrolein at 110–120° in 60–70% yield. The addition leads to the formation of products containing the silyl group in the α-position to the functional group of the unsaturated compound. 2. A definite correlation was found between the ability of the unsaturated compound to form a π-complex with nickel tetracarbonyl and the tendency for silicon hydrides to undergo addition in presence of nickel tetracarbonyl.

Addition of alkylchlorosilanes to unsaturated compounds in presence of chloroplatinic acid

1. In the competing addition of silanes to ethylene in presence of H2PtCl6 the activity of the silanes is determined both by the inductive effect and the steric effect of the silyl groups, but the influence of the steric factor is greater than when the catalyst is platinum on a support. 2. Substituents have a deactivating influence on the ability of the double bond of an unsaturated compound to add on silanes in presence of H2PtCl6 and supported Pt. This is evidently also associated with the steric and inductive influence of these substituents. 3. The facts now known about the addition of silanes to unsaturated compounds in presence of both H2PtCl6 and supported Pt are better explained by the assumption of a specific radical mechanism rather than an ionic reaction mechanism. The specificity of this process is associated with the role of the catalyst surface or of complex-forming forces. 4. On the basis of the addition of silanes to unsaturated compounds in presence of H2PtCl6 and supported Pt, a convenient and high-yielding method of synthesis of a series of silicoorganic compounds of practical importance was developed.

Addition of silanes containing silicon- attached hydrogen to unsaturated compounds in presence of platinized charcoal

1. It was shown that in the addition reaction between silanes containing silicon-attached hydrogen and unsaturated compounds in presence of platinized charcoal the structures of the reactants greatly affect the course of reaction: the highest yield of addition products is given by silanes of the types RSiHCl2 and R2SiHCl and by unsaturated compounds having “active” double bonds. 2. It was found that the addition of CH3SiHCl2 and of C2H5SiHCl2 to F2C=CF2 is accompanied by a telomerization reaction. 3. It was shown that it is possible to prepare silanes of the type RR'SiHBr by reaction of RSiHCl2 with R'MgBr and to prepare also compounds having a four-membered ring including a silicon atom by the cyclization, with the aid of magnesium, of γ-chloro compounds containing at least one silicon-attached chlorine atom.

Stability of Unsaturated Compounds in Presence of Catalysts.

Stability of Unsaturated Compounds in Presence of Catalysts.

Societies and Academies

Societies and Academies