Organosilicon Polymers. III. Infrared Spectra of the Methylpolysiloxanes

Wright, N.; Hunter, M. J.

doi:10.1021/ja01196a018

Cited by 253 publications

(92 citation statements)

References 4 publications

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“…It can be seen in Figure 10 how different the Silopren E 3078 spectra are in comparison with the engine oil used in the engine, except in the 1090 -1020 cm -1 band. The main component of the Silopren E 3078 is the [(CH 3 ) 2 SiO] x which is characterized by two strong bands in different spectral positions of 1090 and 1020 cm -1 with similar absorbance amplitude [23][24][25]. Therefore it can be concluded that the mineral engine oil used was contaminated with the organ-osilicon compound with a polidimetil siloxane structure [(CH 3 ) 2 SiO] x .…”

Section: Figmentioning

confidence: 99%

Analysis of damage caused by siloxanes in stationary reciprocating internal combustion engines operating with landfill gas

Alvarez-Florez

Egusquiza

2015

Engineering Failure Analysis

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Failures in reciprocating internal combustion engines operating with landfill gas are not uncommon. In general, damage is located in the combustion chamber surfaces and in the ring grooves, where a layer of non-volatile combustion products is deposited. These deposits attached to the surfaces reduce heat transfer and increase inner temperature, which produces a knocking phenomena damaging the crank bearings and fusing of the piston head material. Lubrication problems also appear due to the formation of a layer of soft paste silicone deposits in the rings grooves, which increases friction losses and accelerates wear on cylinder and rings. In this paper, some typical examples of damaged engines are presented. The deposits found were analysed using Scanning Electron Microscope and Energy Dispersive X-ray Spectroscopy (SEM-EDX). Additionally, the engine oil used was also analysed by Infra-Red Spectrometry (IR) and the results were compared with known organo-compounds. A method to detect incipient failure caused by organo-compounds contained in landfill gas is introduced. Silica appears in the layers covering the combustion chamber, as well as silicone compound in the top cylinder zone, piston and ring grooves. Damage is associated with siloxanes (organo-silicon compounds) contained in the landfill gas, which decompose in the combustion chamber, generating silicic acid and formaldehyde under the high temperature conditions throughout the combustion processes. Dear EditorThank you for agreeing to review the following manuscript, we would like to thank also the reviewers for the previously received comments. We want to extend our appreciation for taking the time and effort necessary to provide such guidance.As suggested by the editor a throughout revision of the paper has been carried out and the comments of the reviewer has been 100 % included in the current version of the manuscript. All changes on the original version of the manuscript appear in red in the current version.The reviewer commented the first half of manuscript, but his recommendations have been extended to the whole manuscript. Reviewer: 1 ADDITIONAL COMMENTS TO THE AUTHOR:The new Research Highlights according the magazine rules has been uploaded. Yours sincerelyJesus Alvarez-Florez *Detailed Response to Reviewers HighlightsThe main types of damage found in ICE using landfill gas have been studied Combustion of fuel with siloxanes produces two types of residues Residues attach to combustion chamber surfaces reducing the heat transfer Residues also attach to piston ring grooves causing lubrication problems A method to prevent damage based in engine oil IR analysis is presented ABSTRACTFailures in reciprocating internal combustion engines operating with landfill gas are not uncommon. In general, damage is located in the combustion chamber surfaces and in the ring grooves, where a layer of non-volatile combustion products is deposited. These deposits attached to the surfaces reduce heat transfer and increase inner temperature, which produces a k...

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Section: Figmentioning

confidence: 99%

Analysis of damage caused by siloxanes in stationary reciprocating internal combustion engines operating with landfill gas

Alvarez-Florez

Egusquiza

2015

Engineering Failure Analysis

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“…Raman spectra in the 250-1400 cm À1 frequency range The frequency region between about 250 and 1400 cm À1 encompasses that of 1 st -order SiAO Raman scattering. Raman bands assignable to SiAC and SiACH 3 vibrations would also occur in this frequency range (e.g., Wright and Hunter, 1947;Burton et al, 1998).…”

Section: Spectroscopy Of C-bearing Meltsmentioning

confidence: 99%

“…Decreased abundance of Q 4 units is consistent with melt depolymerization. Bonding of Si to C or CH 3 groups would be detectable as bands assignable to SiAC and SiACH 3 stretching in the 800-900 cm À1 and 1250-1300 cm À1 frequency ranges, respectively (Wright and Hunter, 1947;Burton et al, 1998). There is no additional Raman intensity in these frequency regions in any of the Raman spectra of (CH 4 + H 2 )-saturated melts.…”

Section: Raman Spectroscopymentioning

confidence: 99%

Solution behavior of reduced COH volatiles in silicate melts at high pressure and temperature

Mysen

Fogel

Morrill

et al. 2009

Geochimica et Cosmochimica Acta

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The solubility and solution mechanisms of reduced CAOAH volatiles in Na 2 OASiO 2 melts in equilibrium with a (H 2 + CH 4 ) fluid at the hydrogen fugacity defined by the iron-wü stite + H 2 O buffer [f H2 (IW)] have been determined as a function of pressure (1-2.5 GPa) and silicate melt polymerization (NBO/Si: nonbridging oxygen per silicon) at 1400°C. The solubility, calculated as CH 4 , increases from $0.2 wt% to $0.5 wt% in the melt NBO/Si-range $0.4 to $1.0. The solubility is not significantly pressure-dependent, probably because f H2 (IW) in the 1-2.5 GPa range does not vary greatly with pressure. Carbon isotope fractionation between methane-saturated melts and (H 2 + CH 4 ) fluid varied by $14& in the NBO/Si-range of these melts. The (C..H) and (O..H) speciation in the quenched melts was determined with Raman and 1 H MAS NMR spectroscopy. The dominant (C..H)-bearing complexes are molecular methane, CH 4 , and a complex or functional group that includes entities with C"CAH bonding. Minor abundance of complexes that include SiAOACH 3 bonding is tentatively identified in some melts. There is no spectroscopic evidence for SiAC or SiACH 3 . Raman spectra indicate silicate melt depolymerization (increasing NBO/Si). The [CH 4 /C"CAH] melt abundance ratio is positively correlated with NBO/Si, which is interpreted to suggest that the (C"CAH)-containing structural entity is bonded to the silicate melt network structure via its nonbridging oxygen. The $14& carbon isotope fractionation change between fluid and melt is because of the speciation changes of carbon in the melt.

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“…The resulting difference spectra were shown in Fig. 1 B (curves b and c), compared with the spectrum of US liquid [8,9]. The difference spectrum c obtained after light irradiation for 10 h almost coincided with the spectrum of US liquid except that the bands were splitted into several bands, and the band at 900 cm' was shifted to higher frequency.…”

Section: Resultsmentioning

confidence: 71%

Photochemical Surface Modification of Polyacrolein Particles by Gaseous Tetramethylcyclotetrasiloxane.

Morita

Tonooka

2001

J. Photopol. Sci. Technol.

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The surface of sedimentary aerosol particles of polyacrolein (polyAC) was chemically modified by 1,3,5,7-tetramethylcyclotetrasiloxane (ITS) vapor under light irradiation with a low pressure mercury lamp and with N2 laser. FT-IR spectra measured with the surfacemodified polyAC particles strongly suggested that Si-0 bond of electronically excited TTS molecule was cleaved and the resulting active end groups produced silacyclobutane structure at one end or Si0-C bond at the other end on the surface of polyAC particles. Prolonged light irradiation with a low pressure mercury lamp produced poly(methylsiloxane) as the major product. From a gaseous mixture of TI'S and AC, composite aerosol particles were produced under irradiation with a medium pressure mercury lamp through a UV31 and a UVD33S filters. Aerosol particle formation process of the gaseous mixture was monitored by measuring monitor (He-Ne laser) light intensity scattered by the aerosol particles which were produced under light irradiation. With increasing partial pressure of TTS, induction period to detect scattered light became longer and the scattered light intensity became weaker. These results strongly suggested that electronically excitedAC molecules were consumed by the chemical reaction with TTS to induce polymerization reaction of US.

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Organosilicon Polymers. III. Infrared Spectra of the Methylpolysiloxanes

Cited by 253 publications

References 4 publications

Analysis of damage caused by siloxanes in stationary reciprocating internal combustion engines operating with landfill gas

Analysis of damage caused by siloxanes in stationary reciprocating internal combustion engines operating with landfill gas

Solution behavior of reduced COH volatiles in silicate melts at high pressure and temperature

Photochemical Surface Modification of Polyacrolein Particles by Gaseous Tetramethylcyclotetrasiloxane.

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