The Physical and Chemical Properties of Alcohols and Phenols Group of Organic Compounds
The study of a whole organic compound would be impossible if each substance could be separately studied as an entity from other substances. That is to imply, its study could be even more difficult than one might currently perceive it. Fortunately, the whole aspect of organic chemistry can be organized into one concept of the functional group (Vollhardt et al. , pg. In this context, the chemistry of alcohols and phenols family of compounds is comprehensively covered based on some commonly known properties. Alcohol that is denatured contains ethanol at very high concertation levels and added poisonous substances like methanol which is another class of alcohol. The thirdly commonly alcohol that is encountered is isopropyl alcohol (2-propanol or rubbing alcohol). This class of alcohol also happens to be toxic.
It possesses the ability to kill germs and temporary lubricating properties. Isopropyl possesses less of hazard properties because it is absorbed through the skin as compared to methanol. 2H2 (g) + CO (g) - CH3OH (l) Ethyl alcohol constitutes the second alcohol member commonly known as ethanol. This class of alcohol is also called grain alcohol because it can be obtained through fermentation of sugar grains. Alternatively, it can be obtained through petroleum refining where H2O is added to ethene. Generally, the system of naming alcohols follow a pattern f R-OH to even higher series of alcohol molecules like the Propanol, n- butanol, n-hexanol, and among others depending on the carbon chain (Silverstein et al. , pg. Purpose: Determination of the alcohol class through their reaction Five drops of different solutions of alcohols (1-butanol, 1-Hexanol, 2-propanol, 2-methylcyclohexanol, 2-methyl-2propanol, unknown alcohol solution) and a phenol solution were carefully placed on separate test tubes and labelled.
5ml of Lucas reagent was separately added to each of the seven test tubes containing different solutions of alcohol. The shaking of each test tubes was done then the observations were recorded. In the case where there no physical change, immersing of the test tubes in a water bath at 60oC for fifteen minutes was done. Iron chloride test Four drops of 1-butanol, 1-Hexanol, 2-propanol, 2-methylcyclohexanol, 2-methyl-2propanol, and a phenol solution added in separate labelled test tubes that were clean and dried. The steps above were repeated for 1-Hexanol, 2-propanol, 2-methylcyclohexanol, 2-methyl-2propanol, and a phenol solution. Results Solubility Compound Solubility in water 1-butanol Colourless, no separate layers 1-Hexanol Colourless, no separate layers 2-propanol Colourless, no separate layers 2-methylcyclohexanol Partially soluble, thin top layer 2-methyl-2propanol Colourless, no separate layers phenol Colourless, no separate layers Unknown Colourless, no separate layers Lucas test and iron III chloride Compound Iron III chloride test colour Time with Lucas test and observation 1-butanol Light yellow colour No reaction after ten minutes 1o 1-Hexanol Yellow colour No reaction after ten minutes 1o 2-propanol Yellow colour Reaction after five minutes 2o 2-methylcyclohexanol Yellow colour Reaction after five minutes 2o 2-methyl-2propanol Pale yellow Immediate reaction 3o phenol Purple Reaction after five minutes 2o Unknown Yellow colour No reaction after ten minutes 1o 0xidation Compound Classification (primary, secondary and tertiary ) Colour with potassium dichromate 1-butanol Primary brown 1-Hexanol Primary Brown spots 2-propanol Secondary Dark purple 2-methylcyclohexanol Secondary brown 2-methyl-2propanol Tertiary Dark purple phenol Secondary Purplish brown Unknown N/A N/A Discussion Solubility As seen in the results, alcohols dissolve in water.
The reason behind their solubility in water is the presence of the OH functional group which has the capability of forming hydrogen bonds in water molecules. The class of alcohols having smaller carbon chains dissolve in water faster than the ones with longer carbon chain. The hydrocarbons of higher carbon chain have molecules that are closely packed hence more energy is needed for breaking the hydrogen bonds with the hydroxyl group. , pg 145). Oxidation Depending on the reaction conditions, 1o alcohols can be oxidized to either carboxylic acids or aldehydes. The 2o alcohols are normally oxidized to becoming ketones. There is no reaction for the case of 3o alcohols since they are not oxidized to in presence of acidified potassium or sodium dichromate solution (Boccardi et al.
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