Search results
Results From The WOW.Com Content Network
Gas phase ion chemistry is a field of science encompassed within both chemistry and physics. It is the science that studies ions and molecules in the gas phase, most often enabled by some form of mass spectrometry. By far the most important applications for this science is in studying the thermodynamics and kinetics of reactions.
The rate for a bimolecular gas-phase reaction, A + B → product, predicted by collision theory is [6] = = ()where: k is the rate constant in units of (number of molecules) −1 ⋅s −1 ⋅m 3.
The higher the proton affinity, the stronger the base and the weaker the conjugate acid in the gas phase.The (reportedly) strongest known base is the ortho-diethynylbenzene dianion (E pa = 1843 kJ/mol), [3] followed by the methanide anion (E pa = 1743 kJ/mol) and the hydride ion (E pa = 1675 kJ/mol), [4] making methane the weakest proton acid [5] in the gas phase, followed by dihydrogen.
An example of such a reaction is the ring closure of cyclopentane biradicals generated from the gas-phase thermal decomposition of 2,3-diazabicyclo[2.2.1]hept-2-ene. [ 20 ] [ 21 ] Transition state theory is also based on the assumption that atomic nuclei behave according to classical mechanics . [ 22 ]
The crossed molecular beam technique was developed by Dudley Herschbach and Yuan T. Lee, for which they were awarded the 1986 Nobel Prize in Chemistry. [3] While the technique was demonstrated in 1953 by Taylor and Datz of Oak Ridge National Laboratory, [4] Herschbach and Lee refined the apparatus and began probing gas-phase reactions in unprecedented detail.
Benzyl chloride is prepared industrially by the gas-phase photochemical reaction of toluene with chlorine: [3] C 6 H 5 CH 3 + Cl 2 → C 6 H 5 CH 2 Cl + HCl. In this way, approximately 100,000 tonnes are produced annually. The reaction proceeds by the free radical process, involving the intermediacy of free chlorine atoms. [4]
For reactions in the gas phase partial pressure is used in place of concentration and fugacity coefficient in place of activity coefficient. In the real world, for example, when making ammonia in industry, fugacity coefficients must be taken into account.
Usually, this mechanism is used in gas phase decomposition and also in isomerization reactions. An example of isomerization by a Lindemann mechanism is the isomerization of cyclopropane. [11] cyclo−C 3 H 6 → CH 3 −CH=CH 2. Although it seems like a simple reaction, it is actually a multistep reaction: cyclo−C 3 H 6 → CH 2 −CH 2 −CH ...