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Title: Reactions of small organic molecules on silver(110)

Abstract

The interaction of two pairs of molecules (1) acetone (CH[sub 3])[sub 2]C=O and isobutylene (CH[sub 3])[sub 2] C=CH[sub 2] and (2) 1,2-propanediol CH[sub 3] CH (OH)CH[sub 2]OH and 1,3-propanediol HOCH[sub 2]CH[sub 2]CH[sub 2]OH with clean and oxygen-activated Ag(110) has been explored to investigate the effects of molecular structure on reactivity. Experimental techniques employed include temperature programmed reaction spectroscopy, isotopic labelling, surface displacement reactions, and electron energy loss spectroscopy. Acetone and isobutylene were studied to explore the relative importance of C=O and C=C bonds in governing the reactivity of structurally similar compounds. Nucleophilic attack by oxygen at the electron-deficient carbonyl carbon in acetone results in reversible formation of the metallacycle (CH[sub 3])[sub 2]COO[sub (a)] at 110 K. Upon heating C-H bond activation by O[sub (a)] occurs near 215 K to yield acetone enolate CH[sub 2]=C(CH[sub 3])O[sub (a)] and evolve H[sub 2]O[sub (g)]. Atomic oxygen activates methyl C-H bonds in isobutylene via an acid-base mechanism. Although the major products are CO[sub 2(g)] and H[sub 2]O[sub (g)], a small amount of (CH[sub 3])[sub 2]C=CH[sub 2(g)] evolves near 310 K. Evidence for the formation of [pi]-2-methylallyl CH[sub 3]C(CH[sub 2])[sub 2(a)] and trimethylenementhane C(CH[sub 2])[sub 3(a)] is presented. The reaction of 1,2-propanediol CH[sub 3] CH(OH)CH[submore » 2] OH with oxygen-activated Ag(110) has been compared with that of 1,3-propanediol HOCH[sub 2]CH[sub 2]CH[sub 2]OH to evaluate the effects of varying the position of O-H bonds in both diols to produce the corresponding dialkoxides.« less

Authors:
Publication Date:
Research Org.:
Stanford Univ., CA (United States)
OSTI Identifier:
6980999
Alternate Identifier(s):
OSTI ID: 6980999
Resource Type:
Miscellaneous
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 2-METHYLPROPENE; CHEMICAL REACTIONS; ACETONE; GLYCOLS; SILVER; ACTIVATION ENERGY; CHEMICAL BONDS; CHEMICAL REACTION KINETICS; MOLECULAR STRUCTURE; TEMPERATURE DEPENDENCE; ALCOHOLS; ALKENES; ELEMENTS; ENERGY; HYDROCARBONS; HYDROXY COMPOUNDS; KETONES; KINETICS; METALS; ORGANIC COMPOUNDS; REACTION KINETICS; TRANSITION ELEMENTS 400201* -- Chemical & Physicochemical Properties

Citation Formats

Ayre, C.R. Reactions of small organic molecules on silver(110). United States: N. p., 1992. Web.
Ayre, C.R. Reactions of small organic molecules on silver(110). United States.
Ayre, C.R. Wed . "Reactions of small organic molecules on silver(110)". United States. doi:.
@article{osti_6980999,
title = {Reactions of small organic molecules on silver(110)},
author = {Ayre, C.R.},
abstractNote = {The interaction of two pairs of molecules (1) acetone (CH[sub 3])[sub 2]C=O and isobutylene (CH[sub 3])[sub 2] C=CH[sub 2] and (2) 1,2-propanediol CH[sub 3] CH (OH)CH[sub 2]OH and 1,3-propanediol HOCH[sub 2]CH[sub 2]CH[sub 2]OH with clean and oxygen-activated Ag(110) has been explored to investigate the effects of molecular structure on reactivity. Experimental techniques employed include temperature programmed reaction spectroscopy, isotopic labelling, surface displacement reactions, and electron energy loss spectroscopy. Acetone and isobutylene were studied to explore the relative importance of C=O and C=C bonds in governing the reactivity of structurally similar compounds. Nucleophilic attack by oxygen at the electron-deficient carbonyl carbon in acetone results in reversible formation of the metallacycle (CH[sub 3])[sub 2]COO[sub (a)] at 110 K. Upon heating C-H bond activation by O[sub (a)] occurs near 215 K to yield acetone enolate CH[sub 2]=C(CH[sub 3])O[sub (a)] and evolve H[sub 2]O[sub (g)]. Atomic oxygen activates methyl C-H bonds in isobutylene via an acid-base mechanism. Although the major products are CO[sub 2(g)] and H[sub 2]O[sub (g)], a small amount of (CH[sub 3])[sub 2]C=CH[sub 2(g)] evolves near 310 K. Evidence for the formation of [pi]-2-methylallyl CH[sub 3]C(CH[sub 2])[sub 2(a)] and trimethylenementhane C(CH[sub 2])[sub 3(a)] is presented. The reaction of 1,2-propanediol CH[sub 3] CH(OH)CH[sub 2] OH with oxygen-activated Ag(110) has been compared with that of 1,3-propanediol HOCH[sub 2]CH[sub 2]CH[sub 2]OH to evaluate the effects of varying the position of O-H bonds in both diols to produce the corresponding dialkoxides.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1992},
month = {Wed Jan 01 00:00:00 EST 1992}
}

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  • Guided-ion beam mass spectrometry techniques are used to study reactions of first row transition metal ions with NH[sub 3], H[sub 2]O, CO, and NO[sub 2]. Other work probes the reactivity of MO[sup +] ions and measures the ionization energy of NO[sub 2]. Reactions of Sc[sup +], Ti[sup +], V[sup +], Co[sup +], Ni[sup +], and Cu[sup +] with ammonia are proposed to proceed via a H-M[sup +]-NH[sub 2] intermediate. Whenever possible state-specific reaction cross sections are derived and lifetimes for M[sup +]..NH[sub 3] collision adducts measured and compared to values calculated from RRKM theory. In the reaction of V[sup +]more » with water a mechanism that involves formation of V[sup +]-OH by decomposition of a H-V[sup +]-OH intermediate, and direct decomposition of the V[sup +]..OH[sub 2] adduct is proposed. Formation of MC[sup +] and MO[sup +], from reaction of Sc[sup +], Ti[sup +], and V[sup +] with CO is rationalized by a direct abstraction mechanism. Reactions of ScO[sup +], TiO[sup +], and VO[sup +] with D[sub 2] lead to M[sup +], MD[sup +] and MOD[sup +] formation. M[sup +] is predominantly formed in an excited low-spin state. Qualitative potential energy surfaces that explain this behavior are given. The 298 K bond energies (in eV) derived from this study are D[sup [degrees]] (Sc[sup +]-OD) = 5.28 [+-] 0.13, D[sup [degrees]](Ti[sup +]-OD) = 4.93 [+-] 0.12, and D[sup [degrees]](V[sup +]-OD) = 4.62 [+-] 0.15. Reaction of Zn[sup +] + NO[sub 2] also forms NO[sub 2][sup +]. This reaction, and other charge transfer reactions give the adiabatic ionization energy, IE(NO[sub 2]) = 9.60 [+-] 0.03 eV.« less
  • In this study, the electron stimulated desorption-ion angular distribution method (ESDIAD) in combination with temperature programmed desorption (TPD), Auger electron spectroscopy (AES) and low energy electron diffraction (LEED) has been used to study dynamical properties of atoms and small molecules adsorbed on single crystal surfaces. Particles desorbed in electrons stimulated desorption (ESD) often show angular distributions peaked about the directions near the chemical bond directions that were ruptured in the ESD process. Using the ESDIAD method the adsorption geometries of CO on the close packed Pt(111) and CO and NO on the stepped Pt(112) single crystal surfaces were studied. Themore » distribution of particles desorbed in ESD about the center of the beam is related to the vibrational motion of the adsorbed particles parallel to the surface. In the present work, vibration of CO on Pt(111) and modification of the vibrational state of CO adsorbed on Pt(111) due to coadsorbed sulfur and selenium, and anisotropic vibration of NO on Pt(112) were studied. A model calculation of ESDIAD patterns quantitatively comparable to the experimental results is also presented. The desorption cross section of a given ESD product is related to the dynamics of the adsorbed and desorbing particles. In the present work isotopic substitution is used to modify the dynamics of CO adsorbed on Pt(111). With increasingly severe regulations on the composition of automotive exhaust gases, oxidation of carbon monoxide on catalytic surfaces is an increasingly important issue for the automative catalysis industry. One of the important questions concerning CO oxidation is whether the reaction is sensitive to the surface structure or not. In the present dissertation, interaction of CO(a) + O(a) on Pt single crystal surfaces was studied.« less
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