UNIVERSITI TEKNOLOGI MARAFAKULTI KEJURUTERAAN KIMIAINSTRUMENTAL CHEMISTRY FOR ENGINEERS (CHE515)

NAME: MUHAMMAD EZZAT AMIR B. MOHD FAIZAL (2012289974) MOHAMMAD HAFIZI B. ABDUL HAMID (2012400594) ABDUL HASEEB B. SALLEH (2012683278) AMIRUL FATHIN B. HASNOL AZMI (2012430122) FATEN FADHLIN BT. MOHD SARIPUDIN (2012485602)GROUP: EH241 (4A)DATE OF SUBMISSION: 06 / 04 / 2014SEMESTER: 4PROGRAMME / CODE: CHE 515SUBMIT TO: MDM KAMARIAH

No.TitleAllocated Marks (%)Marks1Abstract/Summary52Introduction53Theory54Methodology/Procedure55Results106Discussion10 7Conclusion5 8Reference / Appendix550

ABSTRACTThe following report presents the results of identification of organic compounds using UV-VIS and IR Spectroscopy. We are provided by six different samples labelled A, C, D, I, J, and K. In order to identify these compounds, we are needed to know its max and its peak of wavelength so that we can know the functional groups in the compounds. After that, we identify the compounds by using the list of possible compounds provided. The results of the compounds are:A = EthanolC = Ethanoic acidD = Ethyl ethanoateI = Benzoic acidJ = BromoethaneK = Diethyl ether

INTRODUCTION

A) UV-Visible SpectroscopyThe discovery of UV radiation was associated with the observation that silver salts darkened when exposed to sunlight. In 1801, a German physicist, Johann Wilhelm Ritter made the hallmark observation that invisible rays just beyond the violet end of the visible spectrum darkened silver chloride-soaked paper more quickly than violet light itself. He called them "oxidizing rays" to emphasize chemical reactivity and to distinguish them from "heat rays", discovered the previous year at the other end of the visible spectrum. The simpler term "chemical rays" was adopted shortly thereafter, and it remained popular throughout the 19th century. The terms chemical and heat rays were eventually dropped in favour of ultraviolet and infrared radiation, respectively. The discovery of the ultraviolet radiation below 200 nm, named vacuum ultraviolet because it is strongly absorbed by air, was made in 1893 by a German physicist Victor Schumann.

A diagram of the components of a typical spectrometer is shown in the following diagram. The functioning of this instrument is relatively straightforward. A beam of light from a visible and/or UV light source (coloured red) is separated into its component wavelengths by a prism or diffraction grating. Each monochromatic (single wavelength) beam in turn is split into two equal intensity beams by a half-mirrored device. One beam, the sample beam (coloured magenta), passes through a small transparent container (cuvette) containing a solution of the compound being studied in a transparent solvent. The other beam, the reference (coloured blue), passes through an identical cuvette containing only the solvent. The intensities of these light beams are then measured by electronic detectors and compared. The ultraviolet (UV) region scanned is normally from 200 to 400 nm, and the visible portion is from 400 to 800 nm.

B) FTIR SpectroscopyThe analysis of infrared light interacting with a molecule is called infrared spectroscopy. Infrared spectroscopy can be analyzed in three ways which is measuring absorption, emission and reflection. IR spectroscopy is mainly used to determine the functional group of molecules. IR spectroscopy measures the vibration of an atom and based on the result, it can classified the atom in its functional group. Generally, stronger bonds and light atoms will vibrate at a high stretching frequency (wave number).A common FTIR spectrometer consists of a source, interferometer, sample compartment, detector, amplifier, A/D convertor, and a computer. The source generates radiation which passes the sample through the interferometer and reaches the detector. Then the signal is amplified and converted to digital signal by the amplifier and analog-to-digital converter, respectively. Eventually, the signal is transferred to a computer in which Fourier transform is carried out. Below is a schematic diagram of an FTIR spectrometer.

THEORYA) Infrared SpectroscopyInfrared light imposed on a molecule will not create electronic transitions but it does contain enough energy to interact with a molecule causing vibrational and rotational changes.For example, the molecule can absorb the energy contained in the incident light and the result is a faster rotation or a more pronounced vibration. The possible rotations are around the axis of symmetry for a given molecule or either of the two perpendicular axis.

Molecular VibrationsThere are two types of molecular vibrations, stretching and bending.Molecules have a bond lengths and angles that represents the average positions about which atoms vibrate.

Stretching VibrationsThe stretching frequency of a bond can be approximated by Hookes Law. In thisapproximation, two atoms and the connecting bond are treated as a simple harmonicoscillator composed of 2 masses (atoms) joined by a spring:

According to Hookes law, the frequency of the vibration of the spring is related tothe mass and the force constant of the spring, k, by the following formula:

Where k is the force constant V is the frequency of the vibration

B) Ultra-violet visible SpectroscopyThe principles is based on the measurement of spectrum of a sample containing atoms or molecules. Spectrum is a graph of intensity of absorbed or emitted radiation by sample verses frequency (v) or wavelength. Spectrometer is an instrument design to measure the spectrum of a compound. There are 2 types of spectroscopy :-

1. Absorption spectroscopy An analytical technique which concerns with the measurement of absorption of electromagnetic radiation. For example, UV (185-400nm) or visible (400-800nm) spectroscopy, IR spectroscopy (0.76-15)

1. Emission spectroscopy An analytical technique in which emission(of particle or radiation) is dispersed according to some property of the emission and the amount of the dispersion is measured. For example, mass spectroscopy.

Lambert-Beer's law The law was first developed by Pierre Bouguer before 1729. It was later attributed to Johann Heinrich Lambert who cited Bouguers findings. The law included path length as a variable that affected absorbance. Later, Beer extended in 1852 the law to include the concentration of solutions, thus giving the law its name Beer-Lambert Law.

Definition and Equation The Beer-Lambert law states that the quantity of light absorbed by a substance dissolved in a fully transmitting solvent is directly proportional to the concentration of the substance and the path length of the light through the solution. The law is written as follows:

I = Power of transmited radiation I0= Initial radiation power

EXPERIMENTAL PROTOCOL

A) Procedure for UV-Visible Spectroscopy

1. A blank is prepared by filling up about of a vial ethanol as a reference. Another blank is filled in another vial up to .2. Both blank are then transferred into two different cuvettes. The cuvettes are handled carefully by holding the translucent sides at all time and never the transparent side to allow the spectrometer to operate smoothly. If there are any fingerprints on the transparent side, simply wipe it with tissue.3. The blanks are then transferred into the UV-Vis Spectrometer. The scanners lid is closed and the machine is left to run.4. When the machine asked for component A, the blank from the sample cuvette is taken out and component A which was filled in a vial up to is inserted into the sample cuvette. The machine is then allowed to run.5. Step 4 is repeated for the compounds C, D, I, J and K.

B) Procedure for FTIR Spectroscopy

1. The software is started by choosing Instrument followed by Scan from the drop-down menu which is on the top of the window. A window will appear which requires the user to name the file. Apply button is clicked after naming the file.2. At the same time, a scan button will appear on the screen. The scan button is clicked while compound A is dropped simultaneously onto the sample plate of the spectrometer. The dropping cannot be stopped until the scanning is finished.3. A spectrum will instantly appear on the computer screen. Accept button is clicked after the computer has completed the spectrum construction. Rescale has to be done to get a clearer spectrum, by choosing a graph format followed by changing the ordinate values of top and bottom. The full graph is the labelled by clicking the label button.4. The labelled spectrum is then copied to excel where the file will be saved.5. Steps 1-4 were repeated by using the compounds C, D, I, J and K. Please note that the sample plate must be cleaned with acetone before dropping the next compound on it.RESULTSA) Sample Ai) UV-Vis Spectroscopy

ii) FTIR Spectroscopy

B) Sample Ci) UV-Vis Spectroscopy

ii) FTIR Spectroscopy

C) Sample Di) UV-Vis Spectroscopy

ii) FTIR Spectroscopy

D) Sample Ii) UV-Vis Spectroscopy

ii) FTIR Spectroscopy

E) Sample Ji) UV-Vis Spectroscopy

ii) FTIR Spectroscopy

F) Sample Ki) UV-Vis Spectroscopy

ii) FTIR Spectroscopy

DISCUSSION1. Compound ABased on the data in the result section, when compound A is analyzed by the UV-Vis, the peak of the wavelength is 210.02 nm and the absorbance value is 1.073. Therefore, when it is compared to the UV-Vis Absorption Maxima Table, the possible functional group of the compound is aromatic alcohol. But UV-Vis spectrometer does not give the specific compound. Thus, the result from FTIR must be considered. When compound A is tested by using the IR spectrometer, the data show two peaks of wavelength. The first peak is at 2973.44 and the second peak is at 3323.74 . Based on the Infrared Correlations Table, the possible functional group for the first peak is Carboxylic Acid O-H Stretch, while the possible functional group for the second peak is Alcohol/Phenol O-H Stretch. Thus, if the results are compared, compound A can be determined as alcohol and based on the question given, compound A can be more accurately determined which is ethanol.

2. Compound B

By using UV-Vis spectrometer, compound B gives the peak at 289 nm and the log molar extinction of the compound is 1.19. When it is compared to the UV-Vis Absorption Maxima Table, the possible functional group of the compound is aromatic amine. The peak given by the FTIR is at 1730 . Based on the Infrared Correlations Table, the possible functional group for the peak is aldehyde and ketone. Next, look at the equation given. When compound A which is ethanol, a 1o alcohol reacts with PCC and used in methylene chloride solution, it became an aldehyde which is in this case is ethanal.

3. Compound CIn the result section, UV-Vis shows that compound C has a peak of 210.19 and the absorbance value is recorded at 1.651. The possible functional group of the compound is carboxyl given by the UV-Vis Absorption Maxima Table. When compound C is tested by using the IR spectrometer, it gives two peaks which is at 1704.71 and 3015.78 . Based on the Infrared Correlations Table, the possible functional group for both peaks are aldehyde/ ketone and carboxylic acid respectively. Compare both spectrometer results with the equation given and the compound can be determined as ethanoic acid.

4. Compound DCompound D gives a peak of wavelength, max at 210.09 nm and absorbance, A = 1.434 when tested by UV-Vis spectrometer. While, by using FTIR, the value of the first peak is at 2984.48 cm-1 and the second peak is 1736.45 cm-1. Based on the UV-Vis Absorption Maxima Table, the functional group is given as aldehyde, aromatic alcohol, carboxyl and ester. UV-Vis spectrometer does not give an accurate reading. The first peak for the FTIR gives a possible functional group of carboxylic acid, while the second peak state that the possible functional group is aldehyde, ketone or ester. FTIR also does not give a specific answer. Based on the equation given, compound D is created when compound A react with compound C. Thus, compound D can be determines as an ester which is ethyl ethanoate.

5. Compound E

By using UV-Vis spectrometer, compound B gives the peak at 210, 220 and 273 nm and the log molar extinction of the compound is 4, 3.86 and 2.86. When it is compared to the UV-Vis Absorption Maxima Table, the possible functional group of the compound is carboxyl and aromatic. The peak given by the FTIR is at 2950 and 1685 . Based on the Infrared Correlations Table, the possible functional group for the first peak is carboxylic acid and the second peak is aromatic C=C bending and alkenyl C=C stretch. Based on both results, it can be concluded that compound E can be determined as citric acid.

6. Compound F

UV-Vis shows that compound F has a peak of below 220 and the log molar extinction, e is recorded at 3.2 and above. The possible functional group of the compound is amine and aldehyde given by the UV-Vis Absorption Maxima Table. When compound F is tested by using the IR spectrometer, it gives two peaks which is at 3430 and 1592 . Based on the Infrared Correlations Table, the possible functional group for both peaks are amine/ alcohol and aromatic respectively. Compare both spectrometer results with the equation given and the compound can be determined as amine which in this case is urea or carbamide.

7. Compound G

UV-Vis shows that compound G has a peak of 178 nm and the log molar extinction is 4.84.. The possible functional group of the compound is acetylide given by the UV-Vis Absorption Maxima Table. When compound G is tested by using the IR spectrometer, it gives two peaks which is at 3037 and 1480 . Based on the Infrared Correlations Table, the possible functional group for both peaks are alkenyl C-H stretch and alkyl respectively. Compare both spectrometer results with the equation given and the compound can be determined as benzene ring.

8. Compound H

By using UV-Vis spectrometer, compound H gives the peak at 260 nm and the log molar extinction of the compound is 243. When it is compared to the UV-Vis Absorption Maxima Table, the possible functional group of the compound is benzene and aromatic amine. The peak given by the FTIR is at 3033 , 1501 and 730 . Based on the Infrared Correlations Table, the possible functional group for the first peak are carboxylic acid and aromatic C-H and the second peak is aromatic C=C bending and the third peak are aromatic C-H bending . Based on both results and the equation given, it can be concluded that compound H can be determined as toluene.

9. Compound I

Compound I gives a peak of wavelength, max at 272.02 and 227 nm and absorbance are, A = 0.4259 and 10 when tested by UV-Vis spectrometer. While, by using FTIR, the value of the first peak is at 2825.56 cm-1, the second peak is 2553.67 cm-1 the last strong peak is at 1678.71 cm-1. Based on the UV-Vis Absorption Maxima Table, the functional group is given as nitrate and aromatic benzene. UV-Vis spectrometer does not give an accurate reading. The first and second peak for the FTIR gives a possible functional group of carboxylic acid, while the third peak state that the possible functional group are alkenyl C=C, aromatic C=C and amide C=0 stretch. FTIR also does not give a specific answer. Based on the equation given, compound I is created when compound G react with compound H. Thus, compound I can be determines as benzoic acid.

10. Compound J

In the result section, UV-Vis shows that compound J has a peak of 210.23 nm and the absorbance value is recorded at 1.854. The possible functional group of the compound are aldehyde , aromatic alcohol, bromide and nitro given by the UV-Vis Absorption Maxima Table. When compound J is tested by using the IR spectrometer, it gives one peak which is at 2979.69 . Based on the Infrared Correlations Table, the possible functional group are carboxylic acid and alkyl C-H stretch. Compare both spectrometer results with the equation given and the compound can be determined as bromoethane.

11. Compound K

Based on the data in the result section, when compound K is analyzed by the UV-Vis, the peak of the wavelength is 254.98 and 210.03 nm and the absorbance value are 0.1564 and 1.21. Therefore, when it is compared to the UV-Vis Absorption Maxima Table, the possible functional group of the compound are aldehyde, aromatic alcohol, bromide ester and nitro. But UV-Vis spectrometer does not give the specific compound. Thus, the result from FTIR must be considered. When compound K is tested by using the IR spectrometer, the data show two peaks of wavelength. The first peak is at 2976.48 and the second peakis at 2859.44 . Based on the Infrared Correlations Table, the possible functional group for the peak is Carboxylic Acid O-H Stretch and alkyl C-H stretch. Thus, if the results are compared, compound K can be determined as diethyl ether and based on the question given.

12. Compound L

For the compound L, UV vis does not give any result because there is no chromophore to be detected. If there is no chromophore, it means that the compound does not contain any double bond. Compound L gives a peak by using FTIR, the value of the first peak is at 2900 cm-1 and the second peak is 1463 cm-1. The first peak for the FTIR gives a possible functional group of alkyl C-H and carboxylic acid while the second peak state that the possible functional group is alkyl C-H stretch. Hence, compound L can be determined as hexane.

CONCLUSIONBased on the discussion and result obtained, it can be concluded that compound A to L is as follows :Compound A = EthanolCompound B = EthanalCompound C = Ethanoic AcidCompound D = Ethyl Ethanoate / AcetateCompound E = Citric AcidCompound F = UreaCompound G = Benzene RingCompound H = TolueneCompoundI = Benzoic AcidCompound J = BromoethaneCompound K = Diethyl EtherCompound L = HexaneTo compare the two spectrometer that were used to obtain the result, Infrared spectrometer yield more accurate result compare to Uv-visible spectrometer. Based on the equation given in the question, it can be assumed that all the listed compound is correct.

REFERENCES

1. D. A. Skoog, F. J. Holler, S. R. Crouch. Principles of Instrumental Analysis, 6th ed. Belmont, CA. Thomson Higher Education. 2007.2. Infrared Spectroscopy, 2010. Available from . [10 March 2014].3. Oliver Thomas, Christopher Burgess, April 2007, UV-visible Spectrophotometry of Water and Wastewater, Kingston, London.4. Uv-visible spectroscopy 2009. Available from: [15 March 2014]