1066-42-8Relevant articles and documents
Methods for detecting silicones in biological matrixes
Kennan,Breen,Lane,Taylor
, p. 3054 - 3060 (1999)
Methods for analyzing for silicon and silicone in biological matrixes were developed. A silicone-specific technique involved microwave digestion of samples in acid solution to rapidly break down the biological matrix while hydrolyzing silicones to monomeric species. The resulting monomeric silanol species were then capped with trimethylsilyl groups, extracted into hexamethyldisiloxane, and analyzed by gas chromatography. In serum, positive identification of silicone species with detection limits below 0.5 μg of Si/mL are possible with this technique. The technique is compared with a silicone-specific technique, 29Si NMR, and a non-silicone-specific technique, ICP-AES. 29Si NMR was far less sensitive, with a detection limit of only 64 μg of Si/mL in serum when analyzing for one compound with a single sharp resonance. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) has potentially lower detection limits, but the technique is not silicone-specific and suffers from species-dependent responses.
Effect of Silyl Ether-functinoalized Dimethoxydimethylsilane on Electrochemical Performance of a Ni-rich NCM Cathode
Jang, Seol Heui,Yim, Taeeun
, p. 3402 - 3406 (2017)
Dimethoxydimethylsilane (DODSi) is used as an interface stabilizing additive through a selective HF scavenging reaction for layered Ni-rich oxide cathodes. Ex situ NMR analyses demonstrated that DODSi effectively removes HF from the electrolyte based on the matched chemical reactivity of Si with F? and O with H+. The cells employing DODSi exhibit higher specific capacity with retention than those cycled with a DODSi-free electrolyte even under in situ HF generating conditions. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma-mass spectroscopy (ICP-MS) analyses indicate that DODSi effectively protects the Ni-rich oxide cathodes against HF corrosion, resulting in improved surface stability of Ni-rich cathodes.
METHOD FOR PRODUCING SILANOLS AND NOVEL SILANOLS
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Paragraph 0053-0054; 0057-0058, (2021/08/13)
PROBLEM TO BE SOLVED: To provide a method for efficiently producing silanols useful as functional chemicals, and to provide novel silanols. SOLUTION: There is provided a method for producing silanols including a reaction step of reacting alkoxysilanes having Si-OR bonds (R represents a hydrocarbon group having 1 to 6 carbon atoms) with water or heavy water in the presence of a catalyst, wherein a method for producing silanols having an Si-OR' bond (R' represents a hydrogen atom or a deuterium atom) is characterized in that the catalyst is an inorganic solid acid catalyst having a regular pore structure. There is also provided novel silanols obtained thereby. SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
Silanol Compound, Composition, and Method for Producing Silanol Compound
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Paragraph 0258; 0259, (2017/07/14)
The purpose of the present invention is to provide silanol compounds that can be used as raw materials of siloxane compounds and the like, and a composition of the silanol compounds, as well as to provide a production method that makes it possible to produce silanol compounds at excellent yield. A composition comprising 5 mass % to 100 mass % of a silanol compound represented by Formulas (A) to (C) can be prepared by devising to produce silanol compounds under water-free conditions, to produce silanol compounds in a solvent having the effect of suppressing the condensation of silanol compounds, and to perform other such processes, the composition being able to be used as a raw material or the like of siloxane compounds because the silanol compounds can be stably present in the resulting composition.
Hydrolysis technology and device for concentrated hydrochloric acid
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Paragraph 0017-0018, (2017/07/23)
The invention provides a concentrated-acid hydrolysis technology. The concentrated-acid hydrolysis technology includes the steps that after hydrolysis raw materials of dimethyldichlorosilane and saturated concentrated hydrochloric acid are reacted in a static mixer, the obtained gas-liquid mixture enters a gas-liquid separation tank A, gas recovered out of the top of the gas-liquid separation tank A, carried dimethyldichlorosilane and carried hydrolysate liquid drops enter a venturi mixer from the side face, the gas-liquid mixture deeply mixed in a main concentrated-hydrochloric-acid fluid enters a gas-liquid separation tank B, concentrated hydrochloric acid recovered out of the bottom of the gas-liquid separation tank B is returned to the venturi mixer through a material pump, the gas recovered out of the top sequentially enters a primary condenser and a secondary condenser, gas-liquid mixture condensed by the primary condenser and the secondary condenser enters a collecting device to collect liquid drops, and after the liquid drops are removed through a demister, the product is delivered to a chloromethane synthesis working section through a buffering tank. By means of the concentrated-acid hydrolysis technology, in the concentrated-acid hydrolysis process, the insufficient reacting problem, the low efficiency problem and the like caused when materials are unevenly mixed are solved, and meanwhile the problems that as gas and liquid are carried, a pipe and a device are blocked are solved.
Formation of silicones mediated by the sponge enzyme silicatein-α
Wolf, Stephan E.,Schlossmacher, Ute,Pietuch, Anna,Mathiasch, Bernd,Schroeder, Heinz-C.,Mueller, Werner E. G.,Tremel, Wolfgang
experimental part, p. 9245 - 9249 (2011/01/11)
The sponge-restricted enzyme silicatein-α catalyzes in vivo silica formation from monomeric silicon compounds from sea water (i.e. silicic acid) and plays the pivotal role during synthesis of the siliceous sponge spicules. Recombinant silicatein-α, which was cloned from the demosponge Suberites domuncula (phylum Porifera), is shown to catalyze in vitro condensation of alkoxy silanes during a phase transfer reaction at neutral pH and ambient temperature to yield silicones like the straight-chained polydimethylsiloxane (PDMS). The reported condensation reaction is considered to be the first description of an enzymatically enhanced organometallic condensation reaction. The Royal Society of Chemistry.
Ammonia catalyzed hydrolysis-condensation kinetics of tetraethoxysilane/ dimethyldiethoxysilane mixtures studied by 29 Si NMR and SAXS
Xu, Yao,Sun, Xianyong,Wu, Dong,Sun, Yuhan,Yang, Yongxia,Yuan, Hanzhen,Deng, Feng,Wu, Zhonghua
, p. 327 - 344 (2007/12/25)
In-situ 29Si liquid-state nuclear magnetic resonance (NMR) was used to investigate the ammonia catalyzed hydrolysis and condensation of the mixed systems of tetraethoxysilane (TEOS) and dimethyldiethoxysilane (DDS) dissolved in methanol. With ammonia catalysis, the hydrolysis reaction orders for TEOS and DDS in the mixed systems remained first order, which is similar to that observed for their corresponding single silane component precursor systems. The hydrolysis rate constant for TEOS in the mixed systems was larger than that of TEOS in the single silane component precursor systems. Meanwhile, the hydrolysis rate constants of DDS in the mixed precursor systems were smaller than those of DDS in the single silane component precursor systems. The hydrolysis and condensation kinetics showed more compatible hydrolysis- condensation relative rates between TEOS and DDS, which remarkably affected the final microstructure of the resulting silica particles. Small angle X-ray scattering (SAXS) experiments showed a typical double fractal structure in the particulate networks. Springer Science+Business Media, LLC 2007.
Atmospheric degradation of volatile methyl-silicon compounds
Tuazon, Ernesto C.,Aschmann, Sara M.,Atkinson, Roger
, p. 1970 - 1976 (2007/10/03)
The current widespread use of poly(dimethylsiloxane)s (PDMS) in a broad range of applications leads to their release into soil environments where they degrade to monomeric products, primarily dimethylsilanediol, most of which enter the atmosphere by volatilization. The major degradation pathway of volatile organosilicon compounds in the atmosphere is expected to be a reaction with hydroxyl (OH) radicals. In this work, the kinetics of the gas- phase reactions of dimethylsilanediol, trimethylsilanol, and tetramethylsilane with the OH radical were measured using a relative rate method which employed the N2H4 + O3 reaction as a nonphotolytic source of OH radicals, with analysis by Fourier transform infrared (FT-IR) spectroscopy in a 5870 L chamber. The measured values of the OH radical reaction rate constants (cm3 molecule-1 s-1) at 298 ± 2 K are as follows: dimethylsilanediol, (8.1 ± 1.0) x 10-13; trimethylsilanol, (7.2 ± 0.8) x 10-13; and tetramethylsilane, (8.5 ± 0.9) x 10-13. These values lead to an estimate of tropospheric lifetimes with respect to reaction with the OH radical of ca. 15 days for these organosilicon compounds. FT-IR spectroscopy and atmospheric pressure ionization mass spectrometry (API-MS) were employed to analyze the products of OH radical- and Cl atom-initiated photooxidations of dimethylsilanediol and trimethylsilanol. Infrared signatures of the probable formate ester intermediate products from both silanols were detected. API-MS analyses indicated the formation of methylsilanetriol from dimethylsilanediol, of both dimethylsilanediol and methylsilanetriol from trimethylsilanol, and of the corresponding intermediate formate esters. Possible reaction mechanisms are discussed. The current widespread use of poly(dimethylsiloxane)s (PDMS) in a broad range of applications leads to their release into soil environments where they degrade to monomeric products, primarily dimethylsilanediol, most of which enter the atmosphere by volatilization. The major degradation pathway of volatile organosilicon compounds in the atmosphere is expected to be a reaction with hydroxyl (OH) radicals. In this work, the kinetics of the gas-phase reactions of dimethylsilanediol, trimethylsilanol, and tetramethylsilane with the OH radical were measured using a relative rate method which employed the N2H4 + O3 reaction as a nonphotolytic source of OH radicals, with analysis by Fourier transform infrared (FT-IR) spectroscopy in a 5870 L chamber. The measured values of the OH radical reaction rate constants (cm3 molecule-1 s-1) at 298 ± 2 K are as follows: dimethylsilanediol, (8.1 ± 1.0) × 10-13; trimethylsilanol, (7.2 ± 0.8) × 1013; and tetramethylsilane, (8.5 ± 0.9) × 10-13. These values lead to an estimate of tropospheric lifetimes with respect to reaction with the OH radical of ca. 15 days for these organosilicon compounds. FT-IR spectroscopy and atmospheric pressure ionization mass spectrometry (API-MS) were employed to analyze the products of OH radical- and Cl atom-initiated photooxidations of dimethylsilanediol and trimethylsilanol. Infrared signatures of the probable formate ester intermediate products from both silanols were detected. API-MS analyses indicated the formation of methylsilanetriol from dimethylsilanediol, of both dimethylsilanediol and methylsilanetriol from trimethylsilanol, and of the corresponding intermediate formate esters. Possible reaction mechanisms are discussed.
Decomposition of Some Organosilicon Compounds under the Action of Concentrated Sulfuric Acid in the Presence of an Oxidant
Varezhkin,Mikhailova,Vokin
, p. 570 - 574 (2007/10/03)
Chemical transformations of some organosilicon compounds of the siloxane and silazane series under the action of concentrated sulfuric acid in the presence of an oxidant were studied, varying the amounts and the order of addition of the reactants. Conditions ensuring the most complete decomposition of the substrates were found. The chemical oxygen demand factors for 21 organosilicon compounds were determined for the first time.
Hydrolysis of oligodimethylsiloxane-α,ω-diols and the position of hydrolytic equilibrium
Spivack,Dorn
, p. 2345 - 2352 (2007/10/03)
The hydrolysis of tetramethyldisiloxane-1,3-diol and hexamethyltrisiloxane-1,5-diol in aqueous solutions has been studied. The position of equilibrium of the system including these compounds, dimethylsilanediol, and water has been determined. Concentrations of these compounds in dilute aqueous solutions were determined by coupling HPLC to ICP analysis for Si and also by extraction into ethyl acetate followed by triethylsilylation and GC analysis. It was found that the siloxanediols hydrolyze to the equilibrium mixture at environmentally significant rates and that dimethylsilanediol dominates the equilibrium in dilute aqueous solution, even at concentrations orders of magnitude above that expected in the environment. The hydrolysis of tetramethyldisiloxane-1,3-diol in water was found to be first order in [H+] and in [phosphate buffer] by studying the rates at pH 3 and 6. The hydrolysis of a mixture of higher oligodimethylsiloxane-α,ω-diols as a suspension in water is also described. The first observation of dimethylsilanediol in an environmental sample is reported. The hydrolysis of tetramethyldisiloxane-1,3-diol and hexamethyltrisiloxane-1,5-diol in aqueous solutions has been studied. The position of equilibrium of the system including these compounds, dimethylsilanediol, and water has been determined. Concentrations of these compounds in dilute aqueous solutions were determined by coupling HPLC to ICP analysis for Si and also by extraction into ethyl acetate followed by triethylsilylation and GC analysis. It was found that the siloxanediols hydrolyze to the equilibrium mixture at environmentally significant rates and that dimethylsilanediol dominates the equilibrium in dilute aqueous solution, even at concentrations orders of magnitude above that expected in the environment. The hydrolysis of tetramethyldisiloxane-1,3-diol in water was found to be first order in [H+] and in [phosphate buffer] by studying the rates at pH 3 and 6. The hydrolysis of a mixture of higher oligodimethylsiloxane-α,ω-diols as a suspension in water is also described. The first observation of dimethylsilanediol in an environmental sample is reported.
