Saturday, February 23, 2019

Fractional Distillation Essay

AbstractAn equimolar mixture of cyclohexane and toluene was dislocated by simple and separateal distillment, apply an empty newspaper column and a copper wash column respectively. Using helium as the lively phase, the distillate was analyzed through attack chromatography. The calculated HETP for the simple distillation was 8.274 cm/ home office and the 3.332 cm/plate for the fractional distillation.Experimental subprogramA copper packed fractional-distillation column was obtained and an apparatus was assembled for fractional distillation. quartet clean, dry fraction collectors were obtained and labeled HETP, fraction 1, fraction 2, and fraction 3 respectively. A volume of 40.0 mL of an equimolar mixture of cyclohexane and toluene was added to a 100.0-mL lash out bottom flask attached to the end of the distillation column. Heating chips were added to the complete bottom flask in order to speed up the thawing process. The 100.0-mL round bottom flask, along with the distill ation column was attached to a ring stand over a soup up source. The mixture was fine heated to a boil. The first five drops were collected in the vial labeled HETP. The liquid for vial 1 began collecting when the temperature was 60 C and continued until it was 85 C. Vial 2 began collecting when the temperature was 86C and continued until it was 99 C. Vial 3 was collected at mode temperature once the remaining liquid cooled. A volume of 1 micro-liter of sever exclusivelyy fraction, including the HEPT was added to the gas chromatography apparatus separately in order for each fraction to be analyzed. For simple distillation, the similar procedure was followed using an empty, clean, and dry column.selective informationTable 1 Simple Distillation ValuesVariablesHETPFraction 1Fraction 2Pot quietustemporary worker range, C-60-8586-100-Empty Vials & cap, g5.45316.84216.48216.842Vial & contents, g5.57828.32330.21123.311Mass of fraction, g0.12511.48113.7296.469 study GC outpouring for Cy93.9461.2430.430 recounting messiness Cy, g104.2767.97633.7770% mass Cy93.3692.6349.550 developed mass Cy, g0.116710.6356.8030Actual ramparts Cy0.001390.126.08080Area GC peak Tol6.684.8730.9874.33Relative mass Tol, g7.0145.113532.52978.047% mass Toluene6.647.3750.45100Actual mass Tol, g0.008384.6156.9266.469Actual moles Tol0.000090.91770.07510.0702Table 2 Fractional Distillation Values (Copper Sponge newspaper column) VariablesHETPFraction 1Fraction 2Pot ResidueTemp range, C67-7071-8586-100-Empty Vials & cap, g5.30416.52815.73616.031Vial & contents, g5.41227.14725.26026.200Mass of fraction, g0.10810.6199.52410.169Area GC peak for Cy49.4378.2240.000Relative mass Cy, g54.86786.82444.40% mass Cy99.588.7663.560Actual mass Cy, g0.10759.4256.0530Actual moles Cy0.00130.1120.06570Area GC peak Tol0.19.9022.9457.86Relative mass Tol, g0.10510.39524.08760.753% mass Toluene0.511.2436.44100Actual mass Tol, g0.00051.1943.47110.169Actual moles Tol0.0000050.01290.03760.1103DiscussionThe Northe rn Pines chemical substance Company specializes in manufacturing chemicals from forest products such as turpentine. To obtain pure -pinene, it must be separated, using fractional distillation, from the other major(ip) component turpentine, -pinene. This company would like to fuddle to a cheaper and longer-lasting packing literal. The objective of this experiment was to separate an equimolar mixture of cyclohexane and toluene by simple and fractional distillation, using an empty column and a copper sponge column respectively. The distillate was analyzed through gas chromatography, using helium as the mobile phase. Helium is a goodly mobile phase because it acts as an unreactive carrier-gas that pushes the samples through the chromatogram. This information was utilise to determine which packing material is about effective by comparison HETP orders which based on the number of theoretical plates each material provides. Using the copper sponge as packing material in the fractio nal distillation column provided a very effective insulation of cyclohexane and toluene.The calculated HETP for simple distillation was 8.274 cm/plate and 3.332 cm/plate for fractional distillation. The fractional distillation was more effective because it had a lour HETP value which means that it has a higher number of theoretical plates for the same column length as the simple distillation. When comparing the purity of the major cyclohexane-rich fraction with the starting mixture (the equimolar mixture of cyclohexane and toluene) of each distillation the packing material improved efficiency by more than six percent. one(a) way to recover cyclohexane with even greater purity would be to heat the starting mixture slowly and steadily instead of rapidly, allowing better insularism of the components.Another way to improve purity is to make sure the column is properly packed (not too tight) and insulated. Different packing materials will involve diverse efficiency for distillation and therefore takings different HETP values. The most efficient packing material used was rascing rings, which provided an HETP of 2.67 cm/plate. The copper sponge material had an HETP value of 3.3 cm/plate, followed by glass beads and spiral copper with 7.5cm/plate and galvanized steel with 12.5 cm/plate. Packing the Northern Pines Chemical Companys 3ft fractionating column with rascing rings would provide 34.2 plates, which meets the minimum demand for separating - and -pinene.Exercises1) HETP=height/platesPorcelain saddles 5 cm= (15 cm )/(x )=3 platesGlass tubing 15 cm= (15 cm )/x=1 plateVigreux Column 8 cm= (24 cm)/x=3 platesTotal plates= 3+3+1-1(boiling flask) = 6 plates2) The HETP value and efficiency of separation can be bear upon by experimental errors. A) If the HETP sample was collected midway through the distillation, the mole fraction of cyclohexanetoluene would be much lower, which would in turn yield a higher HETP value. B) If all of the liquid distilled within 5 legal proceeding of heating, a higher HETP value would be found again because all of the toluene would be distilled as well. This also means poor separation. C) If deuce packed columns were stacked over the boiling flask instead of one, the HETP value remain the same if the columns were identical because the height and number of plates would be the same.

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.