Dehydration of Alcohols Essay

Abstract The desiccation of cyclohexanol to cyclohexene can be done through fractional distillment. Once the fraction has been collected it must so be dried. The dried distillation is eventually tested to find whether or non it has been dehydrated. The three trials used were infrared spectrometry. Bromine chemical trial and Bayer’s chemical trial. The infrared spectrometry showed a big narrow extremum at 3062. 12 ( cm-1 ) and 3020. 71 ( cm-1 ) which indicates that there is a dual bond nowadays. To guarantee the consequences were correct the chemical trials were done.

The Bromine trial was found to be positive for cyclohexene. The OH group was removed from the cyclohexanol and replaced with a dual bond found around 3062. 12 ( cm-1 ) and 3020. 71 ( cm-1 ) and the desiccation was successful. Introduction Fractional distillment can be used when seeking to desiccate intoxicants. Dehydrating an intoxicant consists of taking away an OH group. Fractional distillment separates the initial compound into separate compounds ; depending on what their boiling point is. Cyclohexanol can be dehydrated to organize cyclohexene.

Infrared spectrometry is used to analyse a compound and can give a dislocation of what chemicals the original mixture is composed of. An illustration of this is the long wide extremum around 3200 ( cm-1 ) which signifies an OH group in the compound. This technique is really utile to assist find what a compound is made of and it can besides be used with NMR to give a chemical construction. Since infrared spectrometry can be used to analyse a compound it can besides be used to verify that you have the right compound. Another manner to make this is to utilize a chemical trial.

There are multiple chemical trials that can be used. one of them being the Br trial. A bromine trial is used to verify whether an OH group is present or non. Another trial is used with KMNO4 to prove whether and olefine is present or non. Using both chemical trials and infrared spectrometry to analyse the substance it will be clear if fractional distillment and the drying agent were able to work together in the procedure of desiccating the intoxicant. Materials and Methods For this experiment. 5. 0-mL of cyclohexanol were weighed and placed in a 25-mL recovery flask.

A magnetic splash saloon was added to the flask. 2. 5-mL of 9 M sulphuric acid was added to the same flask and mixture was swirled. The fractional distillment setup was set up with steel wool in the column. A 10-mL receiving flask was placed in an ice-water bath. Fractional distillment was started doing certain to keep the caput temperature between 80 and 85°C. doing certain it did non travel over 90°C. Heating was stopped one time the mixture turned dark brown and a deep green condensate formed. Distillate was so collected and transferred to a 25-mL Erlenmeyer flask.

Anhydrous K carbonate was added with a spatula to the 25-mL Erlenmeyer flask. Flask was swirled on occasion for approximately 15 min while adding more anhydrous K carbonate until liquid no longer looked cloudy. The mixture left that was non distilled was neutralized by adding hydrogen carbonate to the solution. easy. until foam Michigans organizing. Dried liquid was so transferred with a Pasteur pipet into a 10-mL recovery flask incorporating a stir saloon for simple distillment. Another 10-mL recovery flask was used as the receiving system and a Ca chloride drying tubing was connected with a vacuity adapter.

The more pure compound was collected by keeping heat from 80 to 85°C. doing certain it did non travel over 90°C. Distillate was weighed and percent output of cyclohexene was determined. An infrared spectrometry was run on the distillation by taking a bead of distillation and seting it in between two salt home bases. Closed the salt plates with metal holders and so set it into the infrared spectrometry machine. First an infrared spectrometry was run on the cyclohexanol. Then an infrared spectrometry was run on the cyclohexene. The Bromine chemical trial was run by adding 2 beads of distillation to a trial tubing.

0. 1 M of Br in methylene chloride was added to the same trial tubing. Then added beads of methylene chloride until colour appeared if colour disappeared the trial would hold been positive. If the colour did non travel away the trial would hold been negative. Finally a Bayer trial was run by adding 2-mL of 95 % ethyl alcohol to a trial tubing. Two beads of distillation were added to the trial tubing. Then KMnO4 was added bead wise until colour persisted. Consequences Table 1. Mass of get downing solution. sulphuric acid. and stoping merchandise formed. Solution| Mass ( g ) | Cyclohexanol| 4. 512| Sulfuric Acid| 3.

384| Cyclohexene| 1. 217| Table 2. Chemical tests done to find whether or non the merchandise was cyclohexene. Result seen by alterations in colour. Type of Test| Color of Starting Reactant| Color of Reactant plus Product| Bromine| Bromine was red| Mixture went from ruddy to clear | Baeyer| KMnO4 was purple| Mixture went from purple to dark brown | Table 3. Infrared spectroscopy extremum values stand foring different constructions found for cyclohexanol and cyclohexene. Solution| Alcohol| Single Bonds ( sp3 C-H ) | Double Bonds ( sp2 C=C ) | Ringing Structure| Cyclohexanol| Peak 13339.

25 cm-1| Peak 2-32930. 94cm-1. 2854. 63cm-1| N/A| Peak 51450. 92cm-1| Cyclohexene| N/A| Peak 8 and 112923. 83cm-1. 2658. 55cm-1| Peak 6-73062. 12cm-1. 3020. 71cm-1| Peak 281438. 15cm-1| The original weight of the cyclohexanol added was 4. 512 g. The original weight of cyclohexanol with sulphuric acid was 7. 896 g. The original weight of the sulphuric acid entirely was 3. 384 g. The weight for the merchandise. assumed to be cyclohexene. was 1. 217 g. The per centum output for cyclohexene was calculated to be 26. 97 % . Cyclohexanol was distilled fractionally to bring forth 4-mL of cyclohexene at 88?

C. The original cyclohexanol was put through infrared spectrometry and was found to hold a big wide set at 3339. 25 ( cm-1 ) bespeaking the presence of an OH group. big narrow sets at 2930. 94 ( cm-1 ) and 2854. 63 ( cm-1 ) bespeaking individual bonds between C and H. and a big narrow set at 1450. 92 ( cm-1 ) bespeaking a ring. The cyclohexene was put through infrared spectrometry which showed that there was no OH group now. This clip there was a dual bond between Cs at 3062. 12 ( cm-1 ) and 3020. 71 ( cm-1 ) . individual bonds between H and C at 2923.

83 ( cm-1 ) and at 2658. 55 ( cm-1 ) . and a ring at 1438. 15 ( cm-1 ) . The bromine chemical trial gave a positive consequence for cyclohexene after one bead of methylene chloride was added. which changed the liquid from a ruddy colour to a clear colour. The Bayer trial made the substance stay purple after 1 bead demoing it was negative for an olefine. Making the bromine chemical trial and the Bayer trial on cyclohexanol gave negative consequences for both. Discussion The fractional distillment was used to desiccate cyclohexanol collected fraction allowed it to be separated and so was dried.

Merely 4-mL of cyclohexene was collected from the distillment. Infrared spectrometry was so used to find whether the substance retrieved from the distillment was dehydrated and had turned to cyclohexene. Looking at the infrared spectrometry of the distilled substance there was no wide extremum which signifies that there is non an Ohio in the substance any longer and the substance is non cyclohexanol any longer. To do certain the substance was cyclohexene two different chemical trials were given. The bromine trial had a positive consequence after 1 bead. The Bayer trial had a negative consequence after one bead was added.

There was a disagreement between the two trials but by sing the IR we can reason that the substance was no longer cyclohexanol. This could be attributed to error such as the cyclohexanol non being distilled right. go forthing drosss. The fractions may hold been heated excessively rapidly and the fractions may hold mixed. There may non hold been adequate drying agent added to the mixture. Some hereafter possible alterations to the experiment would be to hold more clip to non experience rushed. This manner it would be easier to heat more easy and do certain that everything is clean go forthing small to no drosss.