Journal of vacuum science & technology, May 1, 1989
This paper is part of an ongoing study of the structure sensitivity of ammonia adsorption on plat... more This paper is part of an ongoing study of the structure sensitivity of ammonia adsorption on platinum. In the work here, the adsorption of ammonia on Pt(111) and Pt(210) are compared using temperature programmed desorption (TPD), single-reflection infrared (IR), electron energy-loss spectroscopy (EELS), and molecular-beam techniques. In addition, the adsorption of ammonia on Pt(111), (5×20)Pt(100), (2×1)Pt(110), Pt(210), and Pt(211) are compared with TPD. It is found that the TPD spectrum of ammonia is similar on Pt(111), Pt(100), Pt(110), Pt(210), and Pt(211). There was always a molecular peak between 310 and 370 K, another peak at 170 K, and a multilayer peak at 120 K. The sticking probability was found to vary by a factor of 10 from Pt(210) to Pt(111). However, the infrared spectrum of ammonia adsorbed on Pt(111) is virtually identical to the EELS of ammonia on Pt(210) after accounting for a difference in the sensitivity of IR and EELS. Analysis of the TPD data indicates that the surface concentration of ammonia is a factor of 100–200 higher on Pt(210) than on Pt(111) at 670 K. By comparison, Pt(210) was found to be at least a factor of 100 more active than Pt(111) for ammonia dissociation at 670 K. There is more work to be done. However, the results so far indicate that the vaariations in sticking probability and residence time play an important role in the variations in rate.
Abstract TPD is used to compare the dissociation of NO on Pt(210) and Pt(410). Flash of a NO-satu... more Abstract TPD is used to compare the dissociation of NO on Pt(210) and Pt(410). Flash of a NO-saturated Pt(210) sample produces a single N 2 peak at 500 °K and two NO Peaks at 440 and 485 °K, with about 70% of the NO dissociating. By comparison, flash of an NO-saturated Pt(410) sample yields a single N 2 peak at 440 °K and negligible NO. These results show that Pt(410) is considerably more active than Pt(210) for NO dissociation even though the step geometry is identical on the two surfaces and the step density is higher on Pt(210). Thus it appears that the active site for NO decomposition on platinum consists of a specific arrangement of atoms and is not just a step on the surface.
ChemInform Abstract Das TPD-Spektrum einer NO-gesättigten Pt(2l0)-Probe besitzt einen N2-Peak bei... more ChemInform Abstract Das TPD-Spektrum einer NO-gesättigten Pt(2l0)-Probe besitzt einen N2-Peak bei 500 K und zwei NO-Peaks bei' 440 und 485 K, wobeiüber 70% des NO dissoziiert sind. NO-gesättigtes Pt(4lO) besitzt einen N2-Peak bei 440 K und zu vernachlässigendes NO, was zeigt, dass Pt(4lO) für die NO-Dissoziation" aktiver ist als Pt(2l0), obwohl die stufenförmige Geometrie der beiden Oberflächen identisch ist und Pt(2l0) eine grössere Stufenfolge besitzt.
The complete series of ethoxy and methyl substituted tetra-sulfidosilanes (EtO) 3-x Me x Si(CH2)3... more The complete series of ethoxy and methyl substituted tetra-sulfidosilanes (EtO) 3-x Me x Si(CH2)3-S4-(CH2)3-SiMe,(OEt) 3-x, with x = 0 - 3, has been prepared via economically favourable and environmentally friendly phase transfer catalysis (PTC) process. UV-absorption spectra and 'H, 13 C, and 29 Si Nuclear Magnetic Resonance spectra of these systems, actually mixtures of silanes of various sulfur chain length ranging from disulfane S2 up to dodecylsulfane S12 with an average sulfur value (rank) of about 3.75, are discussed in dependence of the varying substitution pattern. Based on the results, response factors in High Pressure Liquid Chromatography analysis are proposed for each sulfane species per silane reflecting the different weight percentage rates of the sulfur chromophore.
The complete series of ethoxy and methyl substituted tetra-sulfidosilanes (EtO) 3-x Me x Si(CH2)3... more The complete series of ethoxy and methyl substituted tetra-sulfidosilanes (EtO) 3-x Me x Si(CH2)3-S4-(CH2)3-SiMe,(OEt) 3-x, with x = 0 - 3, has been prepared via economically favourable and environmentally friendly phase transfer catalysis (PTC) process. UV-absorption spectra and 'H, 13 C, and 29 Si Nuclear Magnetic Resonance spectra of these systems, actually mixtures of silanes of various sulfur chain length ranging from disulfane S2 up to dodecylsulfane S12 with an average sulfur value (rank) of about 3.75, are discussed in dependence of the varying substitution pattern. Based on the results, response factors in High Pressure Liquid Chromatography analysis are proposed for each sulfane species per silane reflecting the different weight percentage rates of the sulfur chromophore.
Temperature programmed desorption (TPD) was used to compare nitric oxide dissociation on Pt(100),... more Temperature programmed desorption (TPD) was used to compare nitric oxide dissociation on Pt(100), Pt(411) and Pt(211). These three faces were chosen for study because they possess sites with nearly the same orbital symmetries. However, the site densities are different on the three faces. It was found that all three faces show nearly identical reactivity for NO dissociation. Measured dissociation fractions were 66, 70 and 66% on the Pt(100), Pt(411) and Pt(211) surfaces respectively. NO dissociation on Pt(100) was inhibited by a (1 x 1)-, (1 x 5) reconstruction, which creates a less active surface during the desorption process. However, the activation energy for N 2 formation was nearly identical (28 kcal/mol) on Pt(211) and Pt(411). Of course many of the features of the TPD spectra varied from face to face. Pt(100) displays a complicated TPD spectrum, due to the presence of surface reconstructions during desorption process. The binding energy of NO on the (100) steps on Pt(211) was found to be unusually strong. However, examination of the data indicates that, except for some minor effects, the variations in reactivity with changing crystal face were as expected from an examination of the symmetries of the orbitals available for reaction, and do not scale with the site density.
The invention relates to an improved production method of the organosilicon compound of the follo... more The invention relates to an improved production method of the organosilicon compound of the following general formula (1). The production method (A) a sulfur, a phase transfer catalyst, a sulfide compound having the formula M (B) to form a mixed product is reacted with a silane compound of the general formula (2) to the intermediate reaction product; And (C) with water or dilute acid solution was added to the mixed product the mixed product organosilicon compound-containing organic phase by phase separation into an aqueous phase and a step of separating the organosilicon compound from the product mixture. Formula 1 Formula 2 Wherein R is independently a monovalent hydrocarbon group of a carbon number of 1 to 12; Alk is a divalent hydrocarbon group having 1 to 18 carbon atoms; m is an integer from 0 to 2, n is a number from 1 to 8; X is Cl, Br or I.
Journal of vacuum science & technology, May 1, 1989
This paper is part of an ongoing study of the structure sensitivity of ammonia adsorption on plat... more This paper is part of an ongoing study of the structure sensitivity of ammonia adsorption on platinum. In the work here, the adsorption of ammonia on Pt(111) and Pt(210) are compared using temperature programmed desorption (TPD), single-reflection infrared (IR), electron energy-loss spectroscopy (EELS), and molecular-beam techniques. In addition, the adsorption of ammonia on Pt(111), (5×20)Pt(100), (2×1)Pt(110), Pt(210), and Pt(211) are compared with TPD. It is found that the TPD spectrum of ammonia is similar on Pt(111), Pt(100), Pt(110), Pt(210), and Pt(211). There was always a molecular peak between 310 and 370 K, another peak at 170 K, and a multilayer peak at 120 K. The sticking probability was found to vary by a factor of 10 from Pt(210) to Pt(111). However, the infrared spectrum of ammonia adsorbed on Pt(111) is virtually identical to the EELS of ammonia on Pt(210) after accounting for a difference in the sensitivity of IR and EELS. Analysis of the TPD data indicates that the surface concentration of ammonia is a factor of 100–200 higher on Pt(210) than on Pt(111) at 670 K. By comparison, Pt(210) was found to be at least a factor of 100 more active than Pt(111) for ammonia dissociation at 670 K. There is more work to be done. However, the results so far indicate that the vaariations in sticking probability and residence time play an important role in the variations in rate.
Abstract TPD is used to compare the dissociation of NO on Pt(210) and Pt(410). Flash of a NO-satu... more Abstract TPD is used to compare the dissociation of NO on Pt(210) and Pt(410). Flash of a NO-saturated Pt(210) sample produces a single N 2 peak at 500 °K and two NO Peaks at 440 and 485 °K, with about 70% of the NO dissociating. By comparison, flash of an NO-saturated Pt(410) sample yields a single N 2 peak at 440 °K and negligible NO. These results show that Pt(410) is considerably more active than Pt(210) for NO dissociation even though the step geometry is identical on the two surfaces and the step density is higher on Pt(210). Thus it appears that the active site for NO decomposition on platinum consists of a specific arrangement of atoms and is not just a step on the surface.
ChemInform Abstract Das TPD-Spektrum einer NO-gesättigten Pt(2l0)-Probe besitzt einen N2-Peak bei... more ChemInform Abstract Das TPD-Spektrum einer NO-gesättigten Pt(2l0)-Probe besitzt einen N2-Peak bei 500 K und zwei NO-Peaks bei' 440 und 485 K, wobeiüber 70% des NO dissoziiert sind. NO-gesättigtes Pt(4lO) besitzt einen N2-Peak bei 440 K und zu vernachlässigendes NO, was zeigt, dass Pt(4lO) für die NO-Dissoziation" aktiver ist als Pt(2l0), obwohl die stufenförmige Geometrie der beiden Oberflächen identisch ist und Pt(2l0) eine grössere Stufenfolge besitzt.
The complete series of ethoxy and methyl substituted tetra-sulfidosilanes (EtO) 3-x Me x Si(CH2)3... more The complete series of ethoxy and methyl substituted tetra-sulfidosilanes (EtO) 3-x Me x Si(CH2)3-S4-(CH2)3-SiMe,(OEt) 3-x, with x = 0 - 3, has been prepared via economically favourable and environmentally friendly phase transfer catalysis (PTC) process. UV-absorption spectra and 'H, 13 C, and 29 Si Nuclear Magnetic Resonance spectra of these systems, actually mixtures of silanes of various sulfur chain length ranging from disulfane S2 up to dodecylsulfane S12 with an average sulfur value (rank) of about 3.75, are discussed in dependence of the varying substitution pattern. Based on the results, response factors in High Pressure Liquid Chromatography analysis are proposed for each sulfane species per silane reflecting the different weight percentage rates of the sulfur chromophore.
The complete series of ethoxy and methyl substituted tetra-sulfidosilanes (EtO) 3-x Me x Si(CH2)3... more The complete series of ethoxy and methyl substituted tetra-sulfidosilanes (EtO) 3-x Me x Si(CH2)3-S4-(CH2)3-SiMe,(OEt) 3-x, with x = 0 - 3, has been prepared via economically favourable and environmentally friendly phase transfer catalysis (PTC) process. UV-absorption spectra and 'H, 13 C, and 29 Si Nuclear Magnetic Resonance spectra of these systems, actually mixtures of silanes of various sulfur chain length ranging from disulfane S2 up to dodecylsulfane S12 with an average sulfur value (rank) of about 3.75, are discussed in dependence of the varying substitution pattern. Based on the results, response factors in High Pressure Liquid Chromatography analysis are proposed for each sulfane species per silane reflecting the different weight percentage rates of the sulfur chromophore.
Temperature programmed desorption (TPD) was used to compare nitric oxide dissociation on Pt(100),... more Temperature programmed desorption (TPD) was used to compare nitric oxide dissociation on Pt(100), Pt(411) and Pt(211). These three faces were chosen for study because they possess sites with nearly the same orbital symmetries. However, the site densities are different on the three faces. It was found that all three faces show nearly identical reactivity for NO dissociation. Measured dissociation fractions were 66, 70 and 66% on the Pt(100), Pt(411) and Pt(211) surfaces respectively. NO dissociation on Pt(100) was inhibited by a (1 x 1)-, (1 x 5) reconstruction, which creates a less active surface during the desorption process. However, the activation energy for N 2 formation was nearly identical (28 kcal/mol) on Pt(211) and Pt(411). Of course many of the features of the TPD spectra varied from face to face. Pt(100) displays a complicated TPD spectrum, due to the presence of surface reconstructions during desorption process. The binding energy of NO on the (100) steps on Pt(211) was found to be unusually strong. However, examination of the data indicates that, except for some minor effects, the variations in reactivity with changing crystal face were as expected from an examination of the symmetries of the orbitals available for reaction, and do not scale with the site density.
The invention relates to an improved production method of the organosilicon compound of the follo... more The invention relates to an improved production method of the organosilicon compound of the following general formula (1). The production method (A) a sulfur, a phase transfer catalyst, a sulfide compound having the formula M (B) to form a mixed product is reacted with a silane compound of the general formula (2) to the intermediate reaction product; And (C) with water or dilute acid solution was added to the mixed product the mixed product organosilicon compound-containing organic phase by phase separation into an aqueous phase and a step of separating the organosilicon compound from the product mixture. Formula 1 Formula 2 Wherein R is independently a monovalent hydrocarbon group of a carbon number of 1 to 12; Alk is a divalent hydrocarbon group having 1 to 18 carbon atoms; m is an integer from 0 to 2, n is a number from 1 to 8; X is Cl, Br or I.
Uploads
Papers by John Gohndrone