Propoxide ion

The Williamson ether synthesis is a nucleophilic substitution reaction. It is an Sn2 reaction because it requires a high concentration of a good nucleophile. If you want to synthesize an ether such as butyl propyl ether, you have a choice of starting materials You can use either a propyl halide and butoxide ion or a butyl halide and propoxide ion. 

The indirect deactivation in 2-amino-4-chloroquinoline (187) requires vigorous conditions (potassium hydroxide in hot ethylene glycol, or boiling propanolic propoxide for 16 hr) to displace the chloro group, which is stable to aqueous alkali and to hydriodic acid. The direct deactivation in 5-amino-2-chloro-3-cyano-6-methyl-pyridine (188) prevents reaction with alkoxide ion under conditions which produce smooth reaction of the des-amino analog. 

Aminoporphyrazines can be prepared by cyclization of tetralkylated diami-nomaleonitrile derivatives, either by themselves or in cocyclizations, using Lin-stead s magnesium propoxide method (7). Although DAMN 98 is commercially available, tetraalkylation is necessary because the unprotected amines do not withstand cyclization. The electron-rich amino pzs function as electron donors, bind metal ions, and undergo a variety of other interesting chemical reactions. 

Ion cyclotron resonance was used to show that 2,2-dimethyl-1,3,2-dioxasilacyclopentane in mixture with PrONO and HC02Me interacts under electron impact with the intermediate methanol-propoxide anion [PrO H OMe] to give a mass peak corresponding to (69) analogous products with two OMe or two OPr groups are absent <84JCS(P2)ll67>. 

In zeolites, this barrier is even higher. As discussed in Section II.B, the lower acid strength and the interaction between the zeolitic oxygen atoms and the hydrocarbon fragments lead to the formation of alkoxides rather than carbenium ions. Thus, extra energy is needed to transform these esters into carbonium ionlike transition states. Quantum-chemical calculations of hydride transfer between C2-C4 adsorbed alkenes and free alkanes on clusters representing zeolitic acid sites led to activation energies of approximately 200 kJ/mol for isobutane/tert-butoxide (29), 230-305 kJ/mol for propane/sec-propoxide, and 240 kJ/mol for isobutane/tert-butoxide (32), 130-150 kJ/mol for ethane/ethene (63), 95-105 kJ/mol for propane/propene, 88-109 kJ/mol for isobutane/isobutylene, and... 

The deamination of n-propylamine by nitrous acid and the deoxideation of n-propoxide both give propene and cyclopropane as the elimination products in a ratio of 9 1 (refs. 619, 620). A similar product ratio is obtained from the thermolysis of 1-diazopropane and this raises the possibility that carbenoid intermediates are also involved in the former reactions. However, the products of deoxideation of 1,1-dideuteropropanol are consistent with a carbonium-ion mechanism involving a 1,3-elimination to give the cyclopropane,... 

Alkyl anions have been implicated as intermediates stabilized by a neutral molecule. Alkoxide ions when photolysed in a pulsed ICR spectrometer dissociate into alkanes and enolate anions The intermediate 19 in equation 25 can be represented by two possible extremes. In 19a the alkyl anion R is solvated by a ketone and inl9b the radical anion of the ketone is solvated by the radical R. The structure of this intermediate will then depend on the relative electron affinities of the alkyl group R and the ketone. Brauman and collaborators photolysed a series of 2-substituted-2-propoxides (18 with R = CH3, R" = H and R varied). For substituents R = CF3, H, Ph and H2C=CH, the C—R bond dissociation energies for homolytic fission are larger than the C—CH3 bond energy, i.e. if the intermediate complex has the structure 19b then methane would be expected to be produced. Conversely, since these R groups form more stable anions than CH3, decomposition via 19a should result in RH. The experimental observation that only RH is formed led to the conclusion that 19 is best described by the solvated alkyl anion structure 19a. 

OPr = i-propoxide). While the edges of this structure are vacant, the face occupation clearly defines a tetrahedral topology in which the four vertices are occupied by the metal ions and the... 

Other preparation methods have recently been developed. Sulfated metal oxides have been prepared by a sol-gel method [42,57,58], which involves the formation of a zirconium-sulfate co-gel by adding sulfuric acid to zirconium n-propoxide in isopropyl alcohol. This one step method appears to be simpler than the two step preparation procedures and allows a better control of the variables. It also allows the direct formation of biiunctional catalysts by the addition of chloroplatinic acid to the gel mixture. A new preparation method, named rapid thermal decomposition of precursors in solution (RTDS), which involves the use of hot pressurized water at hydrotheimal conditions to force metal ion precursors to go into phases of oxyhydroxides and oxyhydrosulfates, has been used to produce sulfated zirconia with crystallite sizes below 100 A [59]. 

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