Analysis of Hydrocarbons 2

Analysis of Hydrocarbons
Myra Gurango, Geneva Guy, Micah Hernandez* and Joyce Lagarde
Department of Chemistry, University of Santo Tomas, Manila, Philippines

Abstract

The organic compounds hexane, toluene, cyclohexene and naphthalene in hexene were subjected to parallel chemical testing to differentiate their intrinsic physical properties in terms of structure and behavior. The physical state and color were noted by simple physical observation. Nitration Testing was conducted for preliminary parallel testing until a positive result of yellow oil was seen. For the second and final testing, oxidation was done through introducing 3 drops of KMnO4 reagent and 2 drops of 10% NaOH solution to 5 drops of the sample organic compound in a test tube. The identity of the hydrocarbon was determined, thus having naphthalene in hexane as the yielded identity of the given sample.

Introduction

Hydrocarbons are compounds that contain only carbon and hydrogen atoms. Hydrocarbons may be divided into two large classes namely: Saturated hydrocarbons and unsaturated hydrocarbons. Saturated hydrocarbons are the simplest type of organic compounds. They are hydrocarbons in which all carbon- carbon bonds are single bonds. An example of a saturated hydrocarbon is an alkane. Unsaturated hydrocarbons are hydrocarbons that contain one or more carbon-carbon multiple bonds like double bonds, triple bonds, or both. Saturated and Unsaturated hydrocarbons have similar physical properties, but their chemical properties are different. Unsaturated hydrocarbons are chemically more reactive than saturated ones. This is because of the presence of carbon-carbon multiple bonds in such compounds and these multiple bonds serve as locations were chemical reactions can occur.

H H H l l l H ---- C ---- H C=C l l l H H H Figure 1. Saturated Hydrocarbon Figure 2. Unsaturated Hydrocarbon

Figure 3. Structure of a cycloalkane Figure 4. Cyclohexene

Cyclohexane is a cycloalkane with the molecular formula C6H12, molar mass of 84.160 g/mol, and boiling point of 80.74°C. It is used as a non-polar solvent and a raw material for the production of adipic acid and caprolactam. Cyclohexane is produced on an industrial scale by reacting benzene with hydrogen.

Cyclohexene is an unsaturated cycloalkene with a chemical formula of C6H10, molar mass of 82.143 g/mol, and a boiling point of 82.98°C. It is not very stable upon long term storage and exposure to light and air should be distilled before use to eliminate peroxides. It has a very sharp smell resembling an oil refinery.

Toluene is an aromatic hydrocarbon without a side chain. It has a molecular formula of C7H8, molar mass of 92.14 g/mol, and a boiling point of 110.6°C. Toluene reacts as a normal aromatic hydrocarbon towards electrophilic aromatic substitution. It is a water-insoluble liquid with a smell of paint thinners, and it is widely used as an industrial feedstock and solvent.

CH3 l

Figure 5. Toluene Figure 6. Naphthalene

Results and Discussion

Experimental

Samples were held in prepared test tubes with their corresponding labels. Before doing any experiment reaction, physical states of toluene, hexane, cyclohexene and naphthalene in hexane were observed under normal room temperature. The color was noted.

Preparation for Reaction 1
(Nitration Test)
5 drops of unknown sample with 8 drops nitrating mixture were mixed and shook well in separate test tubes. Visible changes were noted.

Preparation for Reaction 3
(Basic Oxidation Test)
5 drops of unknown sample, 3 drops of KmnO4 reagent and 2 drops of 10% NaOH were mixed together in separate test tubes. The mixture was placed in a water bath for two minutes. Visible changes were noted.

References
[1] http://www.scribd.com/doc/25377353/Classification-Tests-for-Hydrocarbons

References: [1] http://www.scribd.com/doc/25377353/Classification-Tests-for-Hydrocarbons