Bromine test

The bromine test is applied first. The organic compound, if a liquid, is treated with 2-3 drops of liquid bromine or (preferably) a solution of bromine in carbon tetrachloride if the organic compound is a solid, it should first be dissolved in cold carbon tetrachloride or chloroform. The rapid absorption of the bromine (and consequent disappearance of the red colour) is a strong indication that the compound is unsaturated, and is therefore undergoing direct addition of the bromine. 

Since, however, some compounds, such as aniline (p. 164), react very rapidly with bromine by substitution, the bromine test should whenever possible be confirmed by the alkaline permanganate test. 

It is essential to apply both tests, since some symmetrically substituted ethylenic compounds (e.g., ilbene C4H5CH=CHCjHj) react slowly under tbe conditions of the bromine test. With dilute permanganate solution the double bond is readily attacked, probably through the intermediate formation of a cis diol ... 

Bromine test. Dissolve 0 2 g. or 0 2 ml. of the compound in 2 ml. of carbon tetrachloride, and add a 2 per cent, solution of bromine in carbon tetrachloride dropwise until the bromine colour persists for one minute. Blow across the mouth of the tube to detect any hydrogen bromide which may be evolved (compare Sections III,6 and 111,11). 

Bromine test The compound to be tested is treated with a few drops of 1 to 5% Br2/CCl4 solution. A positive test is indicated by decolonization of the bromine color. 

Alkenes Bromine test Permanganate test Solubility in cone, sulfuric acid Positive for all alkenes Positive for all alkenes All alkenes dissolve... 

Alkynes Bromine test Permanganate test Silver nitrate Sodium metal addition Sulfuric acid Positive for all alkynes Positive for all alkynes Positive for all terminal alkynes only Positive for all terminal alkynes only Positive for all alkynes... 

Hydrocarbon Combustion Bromine Test KMn04 Test h2so4 Test... 

The author expresses his sincere thanks to the following persons who have provided data and/or information for this chapter R.E. Hall for solid-state data G. Havner for confirming the bromine test D.D. Taylor for partition coefficients, UV, MS, and NMR data R. Conroe and S. Spruill for the svnthesis and B. Scott and P. Ritter for analytical data on 1-naphthylacetylethylenediamine, all at Alcon Laboratories Professor John Baker, Department of Medicinal Chemistry, University of Mississippi, Oxford, Mississippi for NMR data and interpretation and Professor Hugo Steinfink, Department of Chemical Engineering, University of Texas, Austin, Texas for x-tay powder diffraction and crystallographic information. 

The double bond of tetrachloroethene is undetectable in the bromine test for unsaturation. Give a plausible explanation... 

Transfer the pot residues from the distillation of spearmint and/or caraway oil to the container for nonchlorinated organic wastes. After performing the prescribed tests on your distillate, put the isolated natural products into appropriately labeled containers. Place the dichloromethane solution from the bromine test for unsaturation in a container for halogenated organic liquids put the manganese dioxide from the Baeyer test for unsaturation in a container for heavy metals. Neutralize and then filter any excess 2,4-dinitrophenylhydrazine solution. Put the filter cake in the container for nonhazardous solids. Flush the filtrate as well as filtrates obtained from recrystallization down the drain. 

Neutralize the residue remaining in the stillpot with 10% aqueous hydrochloric acid then flush it down the drain. Place the dichloromethane solution from the bromine test for unsaturation in a container for halogenated organic liquids put the manganese dioxide from the Baeyer test for unsaturation in a container for heavy metals. 

Analysis Weigh the product and calculate the percent yield determine its melting point. The melting point of pure A/-cinnamyl-m-nitroaniline is 106-107 °C. Perform the qualitative test for unsaturation using the bromine test (Sec. 25.8A) on your product, and record your observations. Obtain IR and NMR spectra of your starting materials, the intermediate imine if isolated, and the product, and compare them with those of authentic samples (Figs. 17.3-17.10). 

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