An experiment was carried out to synthesise cyclohexene by the desiccation of cyclohexanol utilizing concentrated acid as a dehydrating accelerator. Subsequently the merchandise was separated from the reaction mixture ( solution alternatively ) by distillment. Analytic techniques like Infrared Spectroscopy and Gas Chromatography were used for placing and quantifying the different components in the reaction mixture. Procedure: The reaction was carried out by blending 7. 3 milliliter of cyclohexanol and 1. 75 milliliter of 85 % H3PO4 in a 50 milliliter unit of ammunition underside flask.
An setup for desiccation of cyclohexanol was set up. with a fractionating column. a distillment arranger. a thermometer. a capacitor. and a vacuity arranger. A gum elastic septum was used to supply a seal between the thermometer and the glasswork. The mixture was so heated at a soft reflux for 5 min. and so at a much stronger reflux to rush up the distillment procedure. It was distilled till the volume in the distillment flask had been reduced to 1 milliliter. The distillation was so transferred to a separatory funnel. and washed with 5 milliliters of H2O.
The beds are separated and the organic bed transferred in an Erlenmeyer flask. Sodium sulfate anhydrous was added to the solution to cut down the H2O content. The liquid was pipetted out. and placed in a unit of ammunition underside flask for the distillment procedure. The distillment setup was set up the same as the fractional distillment. except for the fractionated Vigreux column. Boling point was so determined during distillment. The distilled merchandise was so transferred to an empty phial. and used for IR ( Infrared Spectroscopy ) & A ; GC ( Gas Chromatography ) .
IR Procedure: In this process the cyclohexanol. cyclohexene. and merchandise was tested. A few beads of each of the solutions was so spread between two Na chloride home bases. and placed in the machine. Sodium chloride was used as it does non absorb strongly in the infrared part whereas glass does. nevertheless it does fade out readily in H2O. A record of the IR was obtained and printed out for analysis. GC Procedure: Gas chromatography involved the distilled merchandise. gasified and injected onto the caput of the chromatographic column.
The sample was so transported through the column by the flow of inert. gaseous nomadic stage. The column itself contains a liquid stationary stage which is adsorbed onto the surface of an inert solid. The start button initiated the process and the information was recorded and printed out. Datas: The information from the Gas Chromatography is presented below: Distilled mass of purified merchandise: 1. 49 gram Final mass of cyclohexene: 2. 02 gm Results & A ; Discussion: The merchandise was a colorless liquid. Mass of the purified merchandise was 1.
49 gm and the concluding mass of cyclohexene was 2. 02 gm. Theoretical output of the merchandise ( cyclohexene ) is 5. 75 gm. Boling point observed during initial distillment was 83. 1 oC. while it was 82. 8 oC during concluding distillment. The value of boiling point during initial distillment is more than the existent boiling point of cyclohexene. This is because of interaction of the solute ( cyclohexene ) with the dissolver ( cyclohexanol ) . H3PO4 i. e. ortho-phosphoric acid used in this experiment was a concentrated strong acid.
A concentrated strong acid is known desiccating agent and really normally used for desiccating intoxicants into quintessences and olefines. Because it was non consumed during the reaction instead was merely assisting the reaction by take parting in its mechanism and acquiring regenerated. hence. its function was that of a accelerator. Infrared ( IR ) spectrum shows characteristic soaking up extremums of different bonds in the molecule ( hypertext transfer protocol: //en. wikipedia. org/wiki/Infrared_Spectroscopy ) . In the IR spectrum of Cyclohexanol. there is a really strong soaking up extremum at 3335 cm-1.
This extremum is characteristic of O-H bond and therefore this is absent in the IR spectrum of Cyclohexene. The soaking up extremum at 1067. 31 cm-1 is characteristic of C-O bond and hence. this is besides absent in the IR spectrum of Cyclohexene. Absorption peaks near 3000 cm-1 are characteristic of C-H bond and hence these extremums are present in the IR spectrum of both Cyclohexanol every bit good as cyclohexene. Similarly. the soaking up peaks matching to C-C bonds in 800 – 1500 cm-1 are present in the IR spectrum of both Cyclohexanol every bit good as Cyclohexene. The soaking up extremum matching to C=C at 1652.
45 cm-1 is present in the IR spectrum of Cyclohexene merely and non in the IR spectrum of Cyclohexanol. Area under Gas Chromatography ( GC ) response curve corresponds to the figure of moles of the species being observing. Therefore spliting the country under Cyclohexene GC curve divided by country under the GC curve of Cyclohexene + Cyclohexanol ; gives the proportion of Cyclohexene in the entire mix. This ratio is ~ 0. 39. This is really near to the existent output of Cyclohexene that was obtained in this experiment. Atom economic system is defined as the molecular weight of the coveted merchandise ( s ) ( here 82.
14 gram per mol for Cyclohexene ) divided by that of the reactant ( s ) ( here 100. 14 gm per mol for Cyclohexanol ) . Therefore. in this experiment the atom economic system is ~82 % . In this experiment. 7. 01 gm Cyclohexanol was used. This corresponds to 0. 07 moles of Cyclohexanol. As one mole of Cyclohexanol can theoretically give 1 mole of Cyclohexene ; hence. in this experiment the theoretical output of Cyclohexene is 0. 07 mole. which is 5. 75 gms. Hence theoretical output of Cyclohexene is 5. 75 gm. Mentions: 1. hypertext transfer protocol: //en. wikipedia. org/wiki/Infrared_Spectroscopy