The production of acrylic acid (CH2CHCO2H) via homogeneous nickel-mediated coupling of ethylene (CH2CH2) and carbon dioxide (CO2) is industrially unattractive at present due to its stoichiometric, rather than catalytic, reaction profile. We utilize density functional theory (DFT) to describe the potential energy surface for both the nickel-mediated coupling reaction and an intramolecular deactivation reaction reported to hinder the desired catalytic activity. The calculated route for the catalytic production of acrylic acid can be divided into three main parts, none of which contain significantly large barriers that would be expected to prohibit the overall catalytic process. Investigation of the catalyst deactivation reaction reveals that the proposed product lies +102.6 kJ mol−1 above the reactants, thereby ruling out this type of pathway as the cause of the noncatalytic activity. Instead, it is far more conceivable that the overall reaction thermodynamics are responsible for the lack of catalytic activity observed, with the solvation -corrected Gibbs free energy of the coupling reaction in question (i.e., CH2CH2 + CO2 → CH2CHCO2H) calculated to be an unfavorable +42.7 kJ mol−1.

The differential cross section for the H + D(2) --> HD + D reaction has been measured using a technique called reaction product imaging. In this experiment, a photolytically produced beam of hydrogen (H) atoms crossed a beam of cold deuterium (D(2)) molecules. Product D atoms were ionized at the intersection of the two particle beams and accelerated toward a position-sensitive detector. The ion images appearing on the detector are two-dimensional projections of the three-dimensional velocity distribution of the D atom products. The reaction was studied at nominal center-of-mass collision energies of 0.54 and 1.29 electron volts. At the lower collision energy, the measured differential cross section for D atom production, summed over all final states of the HD(v,J) product, is in good agreement with recent quasi-classical trajectory calculations. At the higher collision energy, the agreement between the theoretical predictions and experimental results is less favorable.

Ab initio molecular orbital calculations have been performed to explore the reaction potential energy surfaces of singlet silylene and germylene with water, methanol, ethanol, dimethyl ether, and trifluoromethanol. We have identified two new reaction channels on each reaction surface, except for reactions involving dimethyl ether. The previously unreported reaction channels involve H2 elimination following the initial formation of an association complex. For reactions involving singlet silylene and water, a simple activated complex theory (ACT) analysis predicts that these newly identified reaction channels are equally likely to be accessed as the previously identified 1,2 hydrogen atom shift channels. For reactions involving singlet germylene and water, a similar ACT analysis predicts that the H2-elimination channels will occur in preference to the 1,2 hydrogen shift. Indeed, the room-temperature rate constants for H2 elimination from the germanium complex are predicted to be approximately 5 orders of magnitude greater than for the H atom migration channel.

We report on the time evolution of the sodium tetrachloroaurate (NaAuCl(4)) chemical properties as a function of soft X-ray exposure in a dried sample on a silicon surface using X-ray photoelectron spectroscopy (XPS). Our investigations provide mechanistic insight into the photoreduction kinetics from Au(III) to Au(I) and then Au(I) to Au(0). We unambiguously show that XPS photoreduction occurs in stepwise fashion via the Au(I) state. Both photoreduction steps undergo first-order kinetics.