Comparative Investigation of Organic Compounds Angelee Noreen Macapagal Macapagal , Martin Raemond Mallabo, Louie Manuel Mallari Re-ann-mae Mendoza, Janine Paula Monta Group 7 2C Pharmacy Organic Chemistry Laboratory
ABSTRACT The experiment’s goal is to differentiate organic compounds. The group performed a solubility test by introducing drops of a sample whether if it’s liquid or solid into clean test tubes and adding solvent drop wise noting the physical and chemical changes. Reaction to litmus paper was observed to determine if the compound is basic or acidic and also determine its solubility in water. The flammability of the organic compounds was tested by placing 3-5 drops of the sample and lighting it with a match, noting if the sample was flammable or not and the color of its flame. In the infrared spectroscopy analysis, the type of principal bond present in the compound is identified using the appendix notes as guide.
INTRODUCTION Organic compounds are the complex compounds of carbon. Because carbon atoms bond to one another easily, hydrogen, nitrogen, and oxygen are the most common atoms that are generally attached to the carbon atoms. Each carbon atom has 4 as its valence number, which increases the complexity of the compounds that are formed. Since carbon atoms are able to create double and triple bonds with other atoms, it further also raises the likelihood for variation in the molecular make-up of organic compounds. Miscibility is the property of liquids to mix in all proportions therefore forming a homogenous solution. Flammability is the measure of the extent to which a material or a substance will support combustion. This is tested through ignition test. Vapor pressure is an important parameter in determining the ease of ignition of a substance or material. Substances are determined by the characteristics of their flame when they burn. Ignition of the compound brings about a chemical change. Some organic compounds decompose and blacken (charring) while others burst into flames. Some compounds produces yellow, sooty flame due to their high carbon content. Some burn with flames that are yellow but produces less soot, while other compounds burn with non-luminous flames. Infrared (IR) spectrometry gives additional information about a compound’s structure. It identifies the type of principal
bond present in the sample compound that may be observed in the IR spectra and give its wave number range. It also identifies the functional group present in the compound. In this experiment, the compounds shall be differentiated in terms of certain intrinsic physical properties, behavior towards ignition, and the infrared spectra of their functional groups. Condensed structural formula of the samples used:
1. Cyclohexane - Cycloalkane
2. DCM – Halogenated CH2Cl2 3.
Ethanol – Alcohol
4. Phenol – Phenol
5. Benzoic Acid – Carboxylic Acid
counted the number of drops of solvent added to a total of 3mL. Any change, warming effects, soluble/insoluble, miscible/immiscible or effervescence was noted. Reaction with Litmus Paper Drops of the sample tested its aqueous solution with red and blue litmus papers. Color changes in both litmus papers were noted. Ignition Test 3-5 drops of the liquid sample and a pinch amount of solid were placed in an evaporating dish and was lighted using a match. Any flame produced and observed was noted.
6. Ethyl Acetate – Ester
7. Ethylamine – Amine
METHODOLOGY A. Compounds Used for Testing: Cyclohexane DCM Ethanol Phenol Benzoic Acid Ethyl Acetate Ethyl Amine B. Procedure
Solubility Properties The sample was introduced in a clean and dry test tube. 4 drops of each sample was added if the sample was a liquid; and 0.1 g of sample was added if the sample was a solid. The solid samples were grinded to increase the surface area. The solvent was added drop wise and
Infrared (IR) Analysis The appendix notes were used to identify the type of principal bond present in the sample compound that may be observed in the IR spectra and its wave number range.
RESULTS AND DISCUSSION Most hydrocarbons tested were colorless. However, many liquid compounds oxidized when stored for a long period of time. Often the oxidized products are intensely colored. The result of the experiment showed that Phenol becomes red orange in color upon oxidation and white crystals for benzoic acid. The odors of the compounds are quite similar but still it has different identity. Solubility properties of organic compounds using H 20 (water), 5% NaOH (Sodium Hydroxide) solution and 5% HCL (Hydrochloric Acid) solution indicates whether the sample is soluble or insoluble and if the sample is miscible and immiscible. Based on the results, Benzoic acid was slightly soluble in H 20; insoluble in 5% NaOH solution and with 5% HCL solution because of the fact that Benzoic acid is a solid matter. While the rest of the compounds that are liquid namely Cyclohexane and DCM were immiscible and immiscible for Phenol when added with 5% HCL soln. As for Ethanol, Ethyl
Acetate and Ethylamine when added with H20,HCL and NaOH it becomes miscible. Reactions with litmus paper indicate the acidity/basicity of the H 20-soluble samples. If it is from Red to Blue the result will be a base indicator and if it is Blue to Red the result will be an Acid indicator. The Litmus paper that retains its color indicates a neutral compound. Solubility of organic compounds in 5% NaOH also reveals the acidity and basicity of the sample. The results of the Ignition test indicate the presence of Unsaturated or high carbon to hydrogen ratio. The degree of luminosity can be assessed by the presence of yellow flame and soot. The Aromatic compounds burn with sooty flame due to the incomplete combustion, which caused the formation of an unburned carbon. In terms of degree of luminosity: aromatic compounds are greater than unsaturated hydrocarbons, which are greater than saturated hydrocarbons.
Complete combustion is indicated by a blue or non-luminous flame and there is more heat than light, which means that the carbon is completely oxidized.
2 C10H22 + 31 O2 -> 20 CO2 + 22 H2O Incomplete combustion is indicated by a yellow or luminous flame and there is much more light than heat; therefore the carbon is not completely oxidized.
2C2H2 + 5O2 = 4CO2 + 2H2O + heat For IR spectrometry, the position of the band depends upon a number of characteristics of a bond. The higher the bond order, the higher the wave number for the stretching vibration for a bond. The IR spectrum can be broken down into three major regions: 1. The functional group region (16004000 cm-1) is the region in which
where functional groups absorb. Most of these absorptions are at least of moderate intensity, and many are quite strong. It is relatively free from overlap or other interferences. 2. The fingerprint region (1000-1600 cm-1) is often quite complex. It is used for band-by-band comparison of the spectrum of a known compound in order to identify the compound. C-O stretching of alcohols esters are easily assigned. 3. The Aromatic region (675-900 cm 1 ) is used to identify the number and relative positions of groups on a benzene ring. C-H bonds occur in this region. Overall, the experiment succeeded in differentiating the organic compounds tested in terms of certain intrinsic physical and chemical properties, the behavior towards ignition, and the infrared spectra of their functional groups.
REFERENCES From Books:
Bayquen, A.V., Cruz, C.T., et al (2009). Laboratory Manual in Organic Chemistry. Quezon City: C&E Publishing Inc
Lambert, J., Shurvell,H.,Lightner D., Cooks G. (1987) QD. Introduction to Organic Spectres. New York: John Wiley & Sons, Inc. Silverstein, R.M., Webster, F.X., Kiemle, D.J. (2005) Spectrometric Identification of Organic Compounds. USA: John Wiley & Sons, Inc Shriner, R., Hermann, C.K.F., Morrill, Curtin, D.Y. (1998) The Systematic Identification of Organic Compounds. 7th ed. New York: John Wiley & Sons, Inc. University of Santo Tomas Department of Chemistry (ed.). (2000). Organic Chemistry Laboratory Experiments Part 1. (unpublished
manual based by the Department of Chemistry, College of Science, University of Santo Tomas) From the Internet http://www.chemenv.titech.ac.jp http://www.chemistryabout.com Dee, S. Wise Geek http://www.wisegeek.com/what-areorganic-compounds.htm 08/25/10 http://firstyear.chem.usyd.edu.au/prelab/e2 8.shtml http://www.orgchem.colorado.edu http://www.scienceteacherprogram.org/che mistry/Paul00-2.html
APPENDICES Table.1 Comparative Investigation of Organic Compounds
Test Compounds Physical State at RT Color Odor
Cyclohexane Liquid
DCM Liquid
Ethanol Liquid
Phenol Liquid
colorless Acid-like
Colorless Acetone-like Odor
colorless Paste-like odor
Test Compounds Solubilty in H20 5% NaOH soln 5% HCL soln Reactions with Litmus Paper Ignition Test
Cyclohexane
DCM
Colorless Strong, pungent odor Ethanol
Phenol
Immiscible Immiscible Immiscible Not Applicable
Immiscible Immiscible Immiscible Not Applicable
miscible miscible miscible Neutral
miscible miscible Immiscible Acidic
Orange Flame; with soot
Non- Flammable
Yellow Flame; with soot
Flammable
Observed Principal IR Peaks (cm-1)
C-H Stretch 3000-2840 C-H Bond 1475-1350 C-C Stretch 1200-800
C-Cl 580-780
C-O Stretch 1230-1000 C-H Bond 1420-1340 O-H Stretch 3700-3100
C-O Stretch 1230-1000 O-H Bond 1420-1340 O-H Stretch 3700-3100
Table 2. Comparative Investigation of Organic Compounds
Test Compounds Physical State at RT Color Odor
Benzoic Acid Solid White crystals Acid-like odor
Ethylamine Liquid Clear and Colorless Ammonia-Like Odor
Slightly soluble
Ethyl Acetate Liquid Clear and Colorless Plastic balloon-like Odor Miscible
Solubilty in H20 5% NaOH soln 5% HCL soln Reactions with Litmus Paper Ignition Test
Insoluble Insoluble Acidic
Miscible Miscible Neutral
Miscible Miscible Basic
Non-Flammable
Orange Flame; not sooty C=O Stretch 1740-1210 C-O Stretch 1245-1190
Orange Flame; not sooty N-H Stretch 3500-3300 & 34003200 N-H Bond 1640-1560 N-H Bond 900-650 C=N Stretch 1330-1030
Observed Principal IR Peaks (cm-1)
O-H stretch 3300-2500 C-O Stretch 1730-1680 O-H Bond 1440-1390 C-O Stretch 1320-1210
Miscible
