112-52-7Relevant articles and documents
Mechanism of dichlorination of n-dodecane and chlorination of 1-chlorododecane adsorbed on ZSM-5 zeolite molecular sieves. A supramolecular structural interpretation
Turro, Nicholas J.,Han, Nianhe,Lei, Xue-Gong,Fehlner, James R.,Abrams, Lloyd
, p. 4881 - 4893 (1995)
The product distributions produced by the photoinduced dichlorination of n-dodecane (nD) and the photoinduced monochlorination of 1-chlorododecane (1CD) adsorbed on two pentasil zeolites (silicalite and LZ-105) have been investigated. The results are explained in terms of a supramolecular model for which the mobile and diffusing chlorination reagents (Cl?/Cl2) enter the zeolite particle from the external surface and diffuse preferentially along the linear channels of the zeolite internal surface that contain immobile adsorbed nD (or 1CD) molecules. The model assumes that the outermost layer of adsorbed substrates is attacked preferentially, that the attack occurs at the proximal end of adsorbed nD molecules closest to the external surface, and that, after the first chlorination, the substrate molecules in an inner layer are protected from chlorination by "blocking" molecules parked in the outer layer. The model describes each substrate molecule adsorbed on the internal surface in terms of supramolecular isomeric structures that are capable of characterizing the specific void space sites occupied by the substrate. A detailed analysis of the results allows the conclusion that the compensating cations tend to be preferentially located in the zigzag channels rather than in the linear channels or intersections and that the variation of selectivity of chlorination with experimental conditions results from redistribution of the isomeric supramolecular structures.
-
Varma,Grover
, p. 2515 (1974)
-
Formamide-Catalyzed Nucleophilic Substitutions: Mechanistic Insight and Rationalization of Catalytic Activity
Hilt, Gerhard,Huy, Peter H.,Kohlmeyer, Corinna,Sch?fer, André
, p. 11567 - 11577 (2020/11/17)
Herein, detailed mechanistic investigations into formamide-catalyzed nucleophilic substitution (SN) of alcohols are reported. Alkoxyiminium chlorides and hexafluorophosphates were synthesized and characterized as a key intermediate of the catalytic cycle. The determination of reaction orders and control experiments indicated that the nucleophilic attack of the formamide catalyst onto the reagent BzCl is the rate-determining step. Linear free energy relationship revealed a correlation between the quantified Lewis basicity strength of formamides by means of 11B NMR spectroscopy and their catalytic activity in SN-transformations. The observed difference in catalytic ability was attributed to the natural bond order charge, dipole moment, and Sterimol parameter B5. Importantly, this rationalization enables the prediction of the capacity of formamides to promote SN-type transformations in general.
Systematic Evaluation of Sulfoxides as Catalysts in Nucleophilic Substitutions of Alcohols
Motsch, Sebastian,Schütz, Christian,Huy, Peter H.
supporting information, p. 4541 - 4547 (2018/09/13)
Herein, a method for the nucleophilic substitution (SN) of benzyl alcohols yielding chloro alkanes is introduced that relies on aromatic sulfoxides as Lewis base catalysts (down to 1.5 mol-%) and benzoyl chloride (BzCl) as reagent. A systematic screening of various sulfoxides and other sulfinyl containing Lewis bases afforded (2-methoxyphenyl)methyl sulfoxide as optimal catalyst. In contrast to reported formamide catalysts, sulfoxides also enable the application of plain acetyl chloride (AcCl) as reagent. In addition, it was demonstrated that weakly electrophilic carboxylic acid chlorides like BzCl promote Pummerer rearrangement of sulfoxides already at room temperature. This side-reaction also provided the explanation, why sulfoxide catalyzed SN-reactions of alcohols do not allow the effective production of aliphatic and electron deficient chloro alkanes. Comparison experiments provided further insight into the reaction mechanism.
