Abstraction

An equimolar mixture of cyclohexane and methylbenzene was separated by simple and fractional distillment. utilizing an empty column and a Cu sponge column severally. Using He as the nomadic stage. the distillation was analyzed through gas chromatography. The deliberate HETP for the simple distillment was 8. 274 cm/plate and the 3. 332 cm/plate for the fractional distillment.

Experimental Procedure

A Cu packed fractional-distillation column was obtained and an setup was assembled for fractional distillment. Four clean. dry fraction aggregators were obtained and labeled HETP. fraction 1. fraction 2. and fraction 3 severally. A volume of 40. 0 milliliter of an equimolar mixture of cyclohexane and methylbenzene was added to a 100. 0-mL unit of ammunition underside flask attached to the terminal of the distillment column. Heating french friess were added to the unit of ammunition underside flask in order to rush up the warming procedure. The 100. 0-mL unit of ammunition underside flask. along with the distillment column was attached to a ring base over a heat beginning. The mixture was finely heated to a furuncle. The first five beads were collected in the phial labeled HETP. The liquid for vial 1 began roll uping when the temperature was 60 C and continued until it was 85 C. Vial 2 began roll uping when the temperature was 86?C and continued until it was 99 C. Vial 3 was collected at room temperature once the staying liquid cooled. A volume of 1 micro-liter of each fraction. including the HEPT was added to the gas chromatography setup individually in order for each fraction to be analyzed. For simple distillment. the same process was followed utilizing an empty. clean. and dry column.

Datas:

Table 1: Simple Distillation Values
VariablesHETPFraction 1Fraction 2Pot Residue
Temp scope. °C-60-8586-100-
Empty Vials & A ; cap. g5. 45316. 84216. 48216. 842
Vial & A ; contents. g5. 57828. 32330. 21123. 311
Mass of fraction. g0. 12511. 48113. 7296. 469
Area GC extremum for Cy93. 9461. 2430. 430
Relative mass Cy. g104. 2767. 97633. 7770
% mass Cy93. 3692. 6349. 550
Actual mass Cy. g0. 116710. 6356. 8030
Actual moles Cy0. 001390. 126. 08080
Area GC extremum Tol6. 684. 8730. 9874. 33
Relative mass Tol. g7. 0145. 113532. 52978. 047
% mass Toluene6. 647. 3750. 45100
Actual mass Tol. g0. 008384. 6156. 9266. 469
Actual moles Tol0. 000090. 91770. 07510. 0702

Table 2: Fractional Distillation Values ( Copper Sponge Column ) VariablesHETPFraction 1Fraction 2Pot Residue

Temp scope. °C67-7071-8586-100-
Empty Vials & A ; cap. g5. 30416. 52815. 73616. 031
Vial & A ; contents. g5. 41227. 14725. 26026. 200
Mass of fraction. g0. 10810. 6199. 52410. 169
Area GC extremum for Cy49. 4378. 2240. 000
Relative mass Cy. g54. 86786. 82444. 40
% mass Cy99. 588. 7663. 560
Actual mass Cy. g0. 10759. 4256. 0530
Actual moles Cy0. 00130. 1120. 06570
Area GC extremum Tol0. 19. 9022. 9457. 86
Relative mass Tol. g0. 10510. 39524. 08760. 753
% mass Toluene0. 511. 2436. 44100
Actual mass Tol. g0. 00051. 1943. 47110. 169
Actual moles Tol0. 0000050. 01290. 03760. 1103

Discussion

The Northern Pines Chemical Company specializes in fabricating chemicals from wood merchandises such as gum terpentine. To obtain pure ?-pinene. it must be separated. utilizing fractional distillment. from the other major constituent gum terpentine. ?-pinene. This company would wish to exchange to a cheaper and longer-lasting wadding stuff. The aim of this experiment was to divide an equimolar mixture of cyclohexane and methylbenzene by simple and fractional distillment. utilizing an empty column and a Cu sponge column severally. The distillation was analyzed through gas chromatography. utilizing He as the nomadic stage. Helium is a good Mobile stage because it acts as an unreactive carrier-gas that pushes the samples through the chromatogram. This information was used to find which packing stuff is most effectual by comparing HETP values which based on the figure of theoretical home bases each stuff provides. Using the Cu sponge as packing stuff in the fractional distillment column provided a really effectual separation of cyclohexane and methylbenzene.

The deliberate HETP for simple distillment was 8. 274 cm/plate and 3. 332 cm/plate for fractional distillment. The fractional distillment was more effectual because it had a lower HETP value which means that it has a higher figure of theoretical home bases for the same column length as the simple distillment. When comparing the pureness of the major cyclohexane-rich fraction with the starting mixture ( the equimolar mixture of cyclohexane and methylbenzene ) of each distillment the packing stuff improved efficiency by more than six per centum. One manner to retrieve cyclohexane with even greater pureness would be to heat the starting mixture easy and steadily alternatively of quickly. leting better separation of the constituents.

Another manner to better pureness is to do certain the column is decently packed ( non excessively tight ) and insulated. Different packing stuffs will hold diverse efficiency for distillment and hence yield different HETP values. The most efficient packing stuff used was “rascing rings. ” which provided an HETP of 2. 67 cm/plate. The Cu sponge stuff had an HETP value of 3. 3 cm/plate. followed by glass beads and coiled Cu with 7. 5cm/plate and galvanized steel with 12. 5 cm/plate. Packing the Northern Pines Chemical Company’s 3ft fractionating column with rascing rings would supply 34. 2 home bases. which meets the minimal demand for dividing ?- and ?-pinene.

Exercises

1 ) HETP=height/plates
Porcelain saddles: 5 cm= ( 15 centimeter ) / ( x ) =3 home bases
Glass Tube: 15 cm= ( 15 centimeter ) /x=1 home base
Vigreux Column: 8 cm= ( 24 centimeter ) /x=3 home bases
Entire plates= 3+3+1-1 ( boiling flask ) = 6 home bases

2 ) The HETP value and efficiency of separation can be affected by experimental mistakes. A ) If the HETP sample was collected halfway through the distillment. the mole fraction of cyclohexane: methylbenzene would be much lower. which would in bend output a higher HETP value. B ) If all of the liquid distilled within 5 proceedingss of warming. a higher HETP value would be found once more because all of the methylbenzene would be distilled every bit good. This besides means hapless separation. C ) If two packed columns were stacked over the boiling flask alternatively of one. the HETP value remain the same if the columns were indistinguishable because the tallness and figure of home bases would be the same.