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The IUPAC acknowledges the three divergent definitions of carbonium ion and urges care in the usage of this term. For the remainder of this article, the term carbonium ion will be used in this latter restricted sense, while non-classical carbocation will be used to refer to any carbocation with C–C and/or C–H σ-bonds delocalized by bridging.
Food grading involves the inspection, assessment and sorting of various foods regarding quality, freshness, legal conformity and market value. [1] [2] Food grading is often done by hand, in which foods are assessed and sorted. [1] [2] Machinery is also used to grade foods, and may involve sorting products by size, shape and quality.
Methylidynetricobaltnonacarbonyl is a molecule that illustrates the kind of reduced carbon species speculated to occur in the Fischer–Tropsch process.. The Fischer–Tropsch process involves a series of chemical reactions that produce a variety of hydrocarbons, ideally having the formula (C n H 2n+2).
The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). [1] Alkylating agents are reagents for effecting alkylation. Alkyl groups can also be removed in a process known as dealkylation. Alkylating agents are often classified according to their nucleophilic or electrophilic ...
This arises from the fact that polar solvents stabilize the formation of the carbocation intermediate to a greater extent than the non-polar-solvent conditions. This is apparent in the ΔE a, ΔΔG ‡ activation. On the right is an S N 2 reaction coordinate diagram. Note the decreased ΔG ‡ activation for the non-polar-solvent reaction ...
It may either destabilize the cation by drawing even more electron density from the carbon or stabilizing by contributing more electron density. The carbocation positive charge can be relieved by an unsaturated carbon-based or heteroatomic substituent through p-donation and/or C-H hyperconjugation by methylene/methyl substituents. In addition ...
The cationic rearrangement contraction proceeds through the loss of a leaving group and the migration of an endocyclic bond to the carbocation. Pinacol type rearrangements are often used for this type of contraction. [20] Like the expansion reaction this proceeds with an electron donating group aiding in the migration.
The mesomeric form of the cyanogroup reacts with the carbocation. The carbocation is attacked by a water, which then loses an hydrogen to form the product. The product then undergoes hydrolysis to form the N-substituted thiocarbamate. The reaction requires the formation of a carbocation and does not work for primary alcohols.