Auwers-Skita rule

What is Auwers-Skita rule? Auwers-Skita rule, also called conformational rule, is an empirical rule related to the physical properties of geometrical isomers and their configurations. This rule was initially proposed, in 1920, simultaneously by Karl von Auwers and by A. Skita, and was restated by Norman Allinger in 1956. This rule was extensively applied during the assignment of the structures … Read more

Kucherov reaction

What is Kucherov reaction? The Kucherov reaction, also referred to as the Kucherov coupling or Kucherov condensation, involves the hydration of acetylenic hydrocarbons in the presence of a catalyst, such as mercuric sulfate HgSO4 or boron trifluoride BF3, and dilute sulfuric acid H2SO4, yielding ketones. The Kucherov reaction is not commonly referred to by its … Read more

Norrish type I and type II reactions

What are Norrish type I and type II reactions? Norrish type I and type II reactions are organic chemical reactions in which an alkene is converted into a carbonyl compound through the action of an ultraviolet light source. The reactions were discovered by the British chemist George Norrish in the 1950s and are named after … Read more

Steglich esterification

What is Steglich esterification? The Steglich catalyst, also known as 4-(N,N-dimethylamino)pyridine (DMAP), was first reported by Litvinenko and Kirichenko in 1967, and subsequently by Steglich in 1969. R, R1, R2 = alkyl, aryl R3 = H, alkyl, aryl (see list of acronyms) DMAP has been widely used as a super acylation catalyst for the preparation … Read more

Wagner-Meerwein rearrangement

What is Wagner-Meerwein rearrangement? The Wagner-Meerwein rearrangement, also known as the Wagner-Meerwein migration or Wagner-Meerwein shift. This reaction is a class of 1,2-rearrangement of carbocation intermediates, from which the migratory group (vinyl, phenyl, alkyl, H, …) (see list of acronyms) rearranges from an adjacent carbon atom to the carbocation center to form a more stable carbocation … Read more

Esters analysis

In esters analysis, most esters are low melting point liquids or solids, many with characteristic floral and fruity odors. Their IR spectra show strong carbonyl bands from 1780 to 1720 cm-1 accompanied by two strong C-O absorptions in the region of 1300 to 1050 cm-1. The main method for the characterization of an ester involves … Read more

Analysis of sulfur compounds (thiols)

In the analysis of sulfur compounds (thiols), due to the different oxidation states of sulfur, there are many compounds that contain sulfur: thiols, sulfides, disulfides, sulfoxides, sulfones, sulfenic, sulfinic and sulfonic acids, etc. Their exhaustive study is beyond the limits of this page. Only as an example we will deal with thiols. They have an … Read more

Analysis of quinones

Quinones are colored crystalline compounds (most of them are yellow) with a pungent odor. They show in the IR spectrum a carbonyl band near 1670 cm-1. Iodide test Most quinones release iodine from acidified potassium iodide solutions. Oximes and semicarbazones Quinones often form oximes and semicarbazones that often do not have the usual structure. Reduction … Read more

Analysis of nitro compounds

In the analysis of nitrocompounds, one of the characteristics of these compounds is that most of them are colorless liquids. They turn yellow when stored. They have characteristic odors, are insoluble in water and are denser than water. Most aromatic nitrocompounds are yellow crystalline solids. In the IR spectrum, they show two strong bands at … Read more

Analysis of ethers

In ether analysis, ethers, like hydrocarbons, are not very reactive but can be distinguished from ethers by the iodinecharge transfer test and by solubility in H2SO4 (not diaryl ethers). When ethers are left to stand exposed to air and light they have a tendency to form highly explosive peroxides. Ferrox paper test Procedure: this paper … Read more