Halide Elimination
Halide Elimination - Related Videos
02:45
Alkyl Halides
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2023
Structural Properties Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape. Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
01:12
Acid Halides to Esters: Alcoholysis
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2025
Alcoholysis is a nucleophilic acyl substitution reaction in which an alcohol functions as a nucleophile. Acid halides react with alcohol to produce esters. The mechanism proceeds in three steps: First, the alcohol acts as a nucleophile and attacks the acyl carbon to form a tetrahedral intermediate. Next, the carbonyl re-forms with the loss of a chloride ion. Lastly, the positively charged intermediate loses a proton to give an ester as the final product along with H3O+, making HCl an...
08:12
Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films
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Cited by 2 •
2017
Here, we present a protocol for the synthesis of CH3NH3I and CH3NH3Br precursors and the subsequent formation of pinhole-free, continuous CH3NH3PbI3-xBrx thin films for the application in high efficiency solar cells and other optoelectronic devices.
01:26
Enhanced Elimination of Poison
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2023
Poison can be effectively removed from the gastrointestinal (GI) tract through various decontamination procedures. Antidotes serve a crucial role in counteracting the effects of poison by inhibiting enzymes responsible for producing harmful drug metabolites. In some cases, these toxic metabolites can be neutralized by endogenous cosubstrates, which are maintained at specific concentrations to prevent interaction with cellular macromolecules and subsequent cell death. Renal excretion is the...
00:51
Radical Formation: Elimination
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2023
Another method of radical formation is the elimination process. It is the opposite of the addition route and is driven by the instability of the radical. For example, as depicted in Figure 1, dibenzoyl peroxide yields a pair of unstable radicals upon homolysis. Given its instability, this radical spontaneously undergoes elimination via a C–C bond cleavage to form a relatively more stable phenyl radical. The mechanism involves cleavage of the bond between the α and β positions with respect to...
FAQs
E2 elimination proceeds through a single concerted step: a strong base removes a hydrogen from the carbon adjacent to the one bearing the halide, while the carbon–halogen bond breaks and the alkene forms. Because these changes occur together, the substrate structure and the reacting base jointly influence which alkene and stereochemical outcome result.
E1 elimination first generates a carbocation, so conditions that stabilize this intermediate favor the pathway. The subsequent loss of a hydrogen produces the alkene. This stepwise sequence differs from E2 elimination because carbocation formation becomes a central mechanistic feature, making substrate structure and the surrounding reaction conditions especially important to the observed outcome.
Regioselectivity, the preference for forming one alkene location over another, depends on substrate structure, base, solvent, and temperature. These variables can change which adjacent hydrogen is removed and therefore which carbon–carbon double bond forms. Examining the possible alkene products helps chemists connect reaction conditions with the distribution of products.
The key distinction is the timing of bond changes. E2 elimination combines base removal of a β-hydrogen, C–X bond cleavage, and alkene formation in one concerted event. E1 elimination separates these events through carbocation formation. Comparing the pathways helps explain why different substrates and conditions can favor different mechanisms and products.
Condition selection begins with the factors identified as influential in the reaction: substrate structure, base, solvent, and temperature. Chemists consider how these variables affect the relative likelihood of E2 or E1 behavior and the alkene outcome. Adjusting the conditions provides a way to study or guide regioselectivity, stereochemistry, and mechanism.
The alkene product provides evidence about both reaction outcome and mechanism. Its position reveals regioselectivity, while its arrangement reflects stereochemical effects associated with the elimination. Comparing products under different conditions can show how substrate structure, base, solvent, and temperature influence the reaction, making product analysis useful in synthetic planning and mechanistic studies.