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The concepts of syn and anti addition are used to characterize the different reactions of organic chemistry by reflecting the stereochemistry of the products in a reaction. The type of addition that occurs depends on multiple different factors of a reaction, and is defined by the final orientation of the substituents on the parent molecule.
Fractional crystallisation can be used to obtain pure para product, relying on the principle that it is less soluble than the ortho and thus will crystallise first. Care must be taken to avoid cocrystallisation of the ortho isomer. [2] Many nitro compounds' ortho and para isomers have quite different boiling points. These isomers can often be ...
For example, when 2-iodobutane is treated with alcoholic potassium hydroxide (KOH), but-2-ene is the major product and but-1-ene is the minor product. [ 1 ] More generally, Zaytsev's rule predicts that in an elimination reaction the most substituted product will be the most stable, and therefore the most favored.
The major product of the addition reaction will be the one formed from the more stable intermediate. Therefore, the major product of the addition of HX (where X is some atom more electronegative than H) to an alkene has the hydrogen atom in the less substituted position and X in the more substituted position.
These positions are thus the most reactive towards an electron-poor electrophile. This increased reactivity might be offset by steric hindrance between activating group and electrophile but on the other hand there are two ortho positions for reaction but only one para position. Hence the final outcome of the electrophilic aromatic substitution ...
It also is helpful for optimizing a reaction with regard to variables such as temperature and choice of solvent. A good example of a substitution reaction is halogenation. When chlorine gas (Cl 2) is irradiated, some of the molecules are split into two chlorine radicals (Cl•), whose free electrons are strongly nucleophilic.
p-Xylene (para-xylene) is an aromatic hydrocarbon. It is one of the three isomers of dimethylbenzene known collectively as xylenes . The p- stands for para- , indicating that the two methyl groups in p -xylene occupy the diametrically opposite substituent positions 1 and 4.
The Curtin–Hammett principle is a principle in chemical kinetics proposed by David Yarrow Curtin and Louis Plack Hammett.It states that, for a reaction that has a pair of reactive intermediates or reactants that interconvert rapidly (as is usually the case for conformational isomers), each going irreversibly to a different product, the product ratio will depend both on the difference in ...