Zenon Foltynowicz

Ruthenium and rhodium complex catalysts for metathesis of silicon olefins

Abstract Synthetic, catalytic, kinetic and mechanistic aspects of the olefin metathesis of vinyl (methyl, alkoxy)-substituted silanes, proceeding in the presence of highly active catalytic systems based on complexes of ruthenium and rhodium, as well as those with various hydride-donor cocatalysts and dioxygen activators, are summarized. Divinyldisiloxanes and divinylsilanes gave polymeric products. The experiments have shown some general features of self-metathesis: the requirement of the alkoxy substituent(s) at silicon; the possibility of initiation of the metathesis only by a substrate; the activation of the catalyst by traces of dioxygen and hydride-donor cocatalysts; the inhibition by any solvent as well as the extreme predominance of vinyl-substituted silanes over the higher alkenylsilane. Intermediates isolated from the reaction of RuCl2(PPh3)3 with alkoxy-substituted silanes additionally enabled a discussion of mechanistic pathways for the generation of metal-carbenes responsible for the metathesis of silicon-olefins. The results of preliminary examinations of successful cross-metatheses of vinyltriethoxysilane with 1-alkenes catalyzed by ruthenium complexes are also presented.

Effect of substituents on silicon on cross-metathesis of vinylsilanes with 1-alkenes in the presence of ruthenium complexes

Abstract Cross-metathesis (disproportionation) of vinyl-substituted silicon compounds containing methyl, alkoxyl, phenyl, trimethylsiloxyl and silatranyl groups at silicon with 1-decene occurs effectively in the presence of benzene solutions of RuCl2(PPh3)3 activated by dioxygen. The nature of the substituent had only minor effects on the initial rate of substrate consumption and ethene evolution. The results obtained are discussed in view of two proposed mechanisms involving a ruthenium—carbene intermediate as well as insertion of alkene into the RuSi bond (and vinylsilane into the RuH bond) with elimination of silylalkene from β-alkylsilyl ligands (ethylene from β-ethylsilyl ligands).

Cross-metathesis of vinyltriethoxysilane with olefins catalyzed by ruthenium complexes

Abstract Synthetic and catalytic studies on cross-metathesis of vinyltriethoxysilane with 1-alkenes, 2-alkenes, branched alkenes, cycloalkenes, styrene, vinylcyclohexene and vinyltrimethylsilane and some functionalized alkenes catalyzed by RuCl3·nH2O and RuCl2(PPh3)3 are presented. Some of the efficient reactions examined can be applied as novel methods for the synthesis of new silicon-containing olefins or new synthetic approaches to well-known olefins. A preliminary kinetic and stoichiometric study also aims to elucidate the mechanism of cross-metathesis and its conditions for synthetic application. The catalytic cycle for cross-metathesis occurs competitively with that for self-metathesis of vinylsilane. The formation of complexes of ruthenium relatively strongly bonded with olefins, e.g. Ru-styrene complex, plays a decisive role in the effective cross-metathesis.

Metathesis of silicon-containing olefins X. Metathesis of vinyltrimethylsilane catalysed by ruthenium complexes☆

Abstract Self metathesis of vinyltrimethylsilane in the presence of an oxygenated benzene solution of RuCl2 (PPh3)3 and RuCl2(PPh3)4 follows an unusual course and yields two products, 1,2-bis(silyl)ethene (E) and 1,1-bis(silyl)ethene, with products of dimerization, namely 1,4-bis(silyl)butenes-2 (E + Z) and butenylsilanes as well as hexamethyldisiloxane. Gaseous ethylene and traces of ethane were also detected. It is proposed that vinylsilane is inserted into the RuSi bond (via ortho-metallation of the ruthenium triphenylphosphine complex) in competition with pathways involving metal-carbene species. Complexes of ruthenium containing no phenylphosphine give stereoselectively only the (E)-product of metathesis (even in the absence of oxygen and hydrosilane co-catalysts) accompanied by traces of the same by-products.

Metathesis of vinylsubstituted silanes in the presence of ruthenium complexes

Abstract Novel synthetic application of the versatile reaction, the metathesis of vinyltrisubstituted silanes and their co-metathesis with alkenes, dienes and allylsilanes, has been reported. Metathesis of vinyltrimethylsilane is efficiently catalysed by many ruthenium complexes yielding E-bis(silyl)ethene and, unexpectedly 1,1-bis(silyl)ethene (only in the presence of phenylphosphine ligand at ruthenium) as main products accompanied by products of dimerization and co-dimerization. A sequence of five pathways initiating two essential mechanisms — by metal carbene species and the insertion of vinylsilane into RuSi (RuH) and β-H (β-Si) elimination of products was proposed.

Metathesis of silicon-containing olefins. IV: Synthesis of 1-triethoxysilyl-1-alkenes by cross-metathesis of vinyltriethoxysilane with 1-alkenes

Abstract 1-(Triethoxysilyl)-1-alkenes of the general formula CH 3 (CH 2 ) n CHCHSi(OC 2 H 5 ) 3 (where n = 3–7) have been prepared by a novel method, viz., by a very effective cross-metathesis of vinyltriethoxysilane with 1-alkenes catalyzed by ruthenium trichloride. A fifteenfold excess of 1-alkene in the reaction mixture gave 1-(triethoxysilyl)-1-alkenes in high yields (78–88% in turn of vinylsilane) and no bis(silyl)ethenes as by-products were observed. Two isomers ( E )/( Z ) ≈ 1, (by GLC) were isolated and identified mainly by 1 H and 13 C NMR spectroscopy.

Microwave pyrolysis as a method of recycling glass fibre from used blades of wind turbines

The possibility of recycling glass fibre-reinforced composites by using microwave pyrolysis was examined. A scrap blade from a wind turbine was fragmented and microwave-pyrolysed. The glass fibre recovered after pyrolysis represented 70% of the initial mass of glass fibre-reinforced composites. The tensile strength of the glass fibre recovered was measured after pyrolysis and compared to the tensile strength of untreated glass fibre. The test showed that the fibres lost about 25% of their tenacity. Non-woven fibre mats were prepared from the recovered fibres. Laminates were then prepared from the non-woven mats obtained, together with virgin glass fibre mats. Mechanical testing of the laminates showed that it is possible to prepare composites using 25 wt% of recycled fibres, with relatively good mechanical properties.

Comparative lca of industrial objects part 1: lca data quality assurance — sensitivity analysis and pedigree matrix

Goal, Scope and BackgroundThe main aim of this paper is to present some methodological considerations concerning existing methods used to assess quality of the LCA study. It relates mainly to the quality of data and the uncertainty of the LCA results. The first paper is strictly devoted to methodological aspects whereas, the second is presented in a separate article (Part II) and devoted mainly to a case study.MethodsThe presented analysis is based on two well-known concepts: the Data Quality Indicators (DQIs) and the Pedigree Matrix. In the first phase, the Sensitivity Indicators are created on the basis of the sensitivity analysis and then linked with the DQIs and the Quality Classes. These parameters indicate the relative importance of input data and their theoretical quality levels. Next, the Weidema’s Pedigree Matrix (slightly modified) is used to establish the values of the new parameter called the Data Quality Distance (DQD) and to link them with the DQIs and Quality Classes. This way the information about the “real” quality levels is provided. Further analysis is performed using the probabilistic distributions and Monte Carlo simulations.Results and DiscussionThanks to this approach it is possible to make a comparison between two types of the quality factors. On the one hand, the sensitivity analysis allows one to check the importance of input data and to determine their required quality. It is done according to the following relation: the higher the sensitivity indicator, the higher the importance of input data and the higher quality should be demanded. On the other hand the data have a certain real quality, not always in accord with the demanded one. To make possible a comparison between these two types of quality, it is necessary to find and develop a common denominator for them. Here, for this purpose the DQIs and Quality Classes are used.ConclusionsIn the further stage of the assessment the DQIs are used to perform the uncertainty analysis of the LCA results. The results could be additionally analysed by using other techniques of interpretation: the sensitivity-, the contribution-, the comparative-, the discernability- and the uncertainty analysis.Recommendations and OutlookThe presented approach is put into practice to conduct the comparative LCA study for the industrial pumps by using the Ecoindicator99 method. Thanks to this, complex analysis of the credibility of the results is carried out. As a consequence, uncertainty ranges for the LCA results of every product system can be determined [1].

Metathetical activity of allylsubstituted silanes in the presence of ruthenium catalyst

Abstract Untypical catalysis by ruthenium complexes in metathetical conversion of allylsubstituted silanes has been observed in which allylsilanes first undergo isomerization to 1-propenyl-trisubstituted silanes which is followed by their cross-metathesis with the parent allylsilanes. The allylsilanes cross-metathesis with some vinylsilanes and 1-alkenes has been found to proceed likewise.

Synthesis of new vinylsilanes containing an asymmetric silicon via platinum catalyzed hydrosilylation of acetylene and monosubstituted alkynes

Abstract A series of new racemic vinylsilanes has been obtained by hydrosilylation reaction of acetylene and monosubstituted alkynes with (±)-α-NpPhMeSiH and (±)-N(CH 2 CH 2 O) 3 SiCH 2 PhMeSiH in the presence of platinum-containing catalysts.