Download Macroscale KEM-KIT® Standard Taper 14/20 Kit

Macroscale KEM-KIT® Standard Taper 14/20 Kit
Kontes® Article No. 269320-0000
The purpose of this manual is to give preliminary guidance to students
using research quality jointed glassware in supervised or advanced
organic chemistry experimentation.
The components of the KEM-KIT® were especially chosen for small
scale operation from standard items with careful consideration of the
problems of surface area, versatility and compatibility with existing
semi-micro laboratory manuals.
Each component has been scaled to function with the smaller 14/20
joint size and the smaller quantities used in semi-micro chemistry.
These kits have been student-tested with several semi-micro manuals,
including those of Campbell and Kline, Cheronis, Kline, Sugihari and
Vogel.
The KEM-KIT® is designed for maximum flexibility with standard types
of glassware components that are commonly found in any organic
research laboratory. There are two primary reasons for using standard
taper glassware in an introductory course. First, considerable classroom
time can be saved in the apparatus setup. Second, and perhaps most
important, students gain valuable experience in techniques that are
required in advanced undergraduate projects and research
laboratories. Techniques developed with this apparatus can be directly
applied to advanced work. Future research efforts will therefore be a
realistic extension of academic training.
This manual was written by Dr. Bruce Campbell Jr., MacMurray College,
Jacksonville IL. Dr. Campbell, Dr. William B. Martin, Lake Forest College,
lake Forest, IL: and Dr. Courtney Benedict, Prof. Emeritus, Chico State
College, Chico CA, are to be jointly credited with the original thought
and development of the Kontes Microscale KEM-KIT®.
A thin film of lubricant must be spread or wiped on the surfaces of
ground joints and stopcocks before fitting to prevent freezing. When
joint members are separated, it is generally best to clean and
relubricate the joint before refitting. These joints may be cleaned with
a cloth moistened with acetone, benzene or chloroform. All the joints
in the 269320 kit are 14/20.
Experiments written for other types of equipment and scales of operation can be adapted to this
equipment with creative interpretation of the directions. The procedure is carefully considered to
anticipate how the flask should be equipped to provide for all operations. The flask should be selected
so that the ultimate volume of contents does not exceed 60-75% of the stated capacity.
It will usually be possible to clamp all the apparatus to one ring stand. This will minimize accidental
openings and breakage due to shifting stands. Once the apparatus is completely clamped and after
subsequent changes, the joints should be checked to insure a proper fit. At best, each piece should be
supported by a clamp. Some alternatives for positive attachment may be approved by the instructor.
The kit is equipped with a thermometer/outlet adapter that has many uses. It can support a gas inlet
or dispersion tube for the introduction of a gas, an air bleed for vacuum distillation, or an outlet to a
gas trap. It allows the insertion of inlet and outlet tubes for an inert atmosphere reaction or the
connection of a series of vessels for a gas reaction. With glass rods, they become extra stoppers. They
hold the thermometer in the vapor space or in the reaction mixture, and support the steam inlet for
steam distillation. They may be equipped as drying tubes. A length of glass tube bent at about 75° a
few centimeters from one end with the long arm containing calcium chloride between two wads of
glass wool and the short arm inserted into the outlet adapter will usually provide adequate drying.
The thermometer is inserted upward through the adapter body and rubber fitting where it is friction
held. The thermometer can then be adjusted to the proper height by moving the edges of the tubing.
Use caution to prevent breakage of the thermometer. In a normal distillation the thermometer should
be so located in the distillation head as to be completely bathed in vapor before any passes the
condenser.
Fig. 1
Fig. 2
Fig. 3
Fig. 4
This item is used as a condenser for reactions requiring reflux (figs 1&2). For this purpose, an air
condenser made of a long piece of glass tubing in an outlet adapter may be attached to it. The Liebig
condenser may also be used in series with the condenser of the distillation head. As a fractionation
column (fig 4) it may be used with or without packing. The packing may be a segment of unreactive
metal scouring sponge or a wire spring. The jacket may be partially evacuated. In fractional
distillations, to maximize recovery of the last fraction, it may be advisable to use an mL of chaser or
remove the column before distilling the last fraction (convert to fig 3). The column may also be used in
simultaneous addition and distillation (fig 6, but modified) between the Claisen adapter and the
distillation head. Alternatively, some fractionation may be obtained by using a little packing in the
sidearm of the Claisen or lower body of the distillation head.
The distillation head is a principal component of all distillation setups. It is chosen because it is
designed to give better temperature readings and to minimize holdup beyond the thermometer. For
the distillation of compounds boiling much above 150 °C, no water should flow in the condenser or
reduced pressure should be used.
The vacuum adapter is commonly used during atmospheric distillation to prevent the loss of product
and contamination. When a flask or receiver is used, the sidearm must be open to the atmosphere.
However, the sidearm may be attached to an exit tube to lead vapors safely away when substances
like ether are being distilled. With this adapter in place, it is possible to complete solvent stripping at
reduced pressure, but there is a danger that some product will distill with the solvent.
Many vessels may be used as receivers, including flasks, both round bottom and Erlenmeyer, regular
test tubes and graduated cylinders. The receiver may be cooled in an ice bath for very volatile
solvents. If a product is to be transferred from a receiver by pouring, the joint lubricant should be
removed first.
Hot water, detergent and scrubbing will clean much of the glassware if begun immediately after the
equipment is used. Some tarry deposits yield to solvents such as acetone or ether and the glassware
then can be cleaned as usual. More difficult spots can usually be removed with careful use of small
amounts of hot concentrated sulfuric acid (CAUTION). While cleaning flasks and tubes, scratches
should be avoided as they may lead to cracking and breakage when the piece is heated. Unnecessary
exposure of joints to strong alkali should also be avoided. Glassware may be dried by rinsing with
acetone or alcohol and air. Drying ovens should be used only for glassware cleaned with water.
Experimentation
This experiment uses an assembly for fractional distillation as in figure 4. The vertical condenser may
have in it a loose strand of stainless steel sponge or coil of unreactive wire, although good results are
obtainable without packing the column.
Fig. 5
Fig. 6
Fig. 7
In the 25 mL flask, place 8 mL of methanol and 8 mL of water or 15 mL of a water-methanol mixture
which is at least one-third water. Heat the flask to initiate boiling. When the ring of condensate has
risen to about the halfway point of the vertical condenser, control the heating so that the ring rises
very gradually. Once the condensate reaches the sidearm of the distillation head, supply only
enough heat to continue the distillation without interruption. Keep a record of the temperature as
each 0.5 mL is collected. Record the values of temperature and volume collected more frequently
when the temperature becomes about constant near 100 °C or until there is little measurable volume
left in the graduated receiver. Discontinue the distillation at this point, or supply a new receiver. Do
not allow the flask to go to dryness.
Plot the change in temperature vs. the volume. Determine the amounts of water and methanol and
calculate the apparent percent of methanol in the original mixture. Ethanol or 2-propanol may be
used in place of methanol. A mixture of benzene or carbon tetrachloride may be fractionated in the
same manner.
Place in a 125 mL Erlenmeyer flask about 7 mL of concentrated nitric acid and add cautiously, in
small portions, 7.5 mL of concentrated sulfuric acid. Cool the mixture to a temperature that can be
held in the hand before the benzene is added. Add the 8 mL of benzene with vigorous swirling to
insure reaction before the next addition. When the flask becomes more than moderately warm to
the touch, cool it in an ice bath or cold water bath. Continue this procedure until all the benzene has
been added. When the reaction appears to have subsided, the flask is immersed in a water bath
maintained between 55-60 °C. Should a violent reaction occur, cool the flask again and shake to
complete the reaction. Re-immerse the flask and repeat if necessary. Keep the flask in the
waterbath, carefully maintained between 50-60 °C, for 20-30 minutes after the last signs of violent
reaction. Occasional shaking is useful. Pour the reaction mixture into 70 mL of water in another flask
and, after thorough mixing, decant as much as possible of the aqueous acid layer before transferring
the remaining material to a separatory funnel. Separate the lower, non- aqueous layer into 15 mL of
cold water. Pour the remaining acid out through the top of the funnel. Rinse the funnel and again
separate the nitrobenzene but this time into 10 mL of 5-10% sodium bicarbonate. When it has been
separated again, dry the nitrobenzene in a small Erlenmeyer with 2-3 g of anhydrous calcium
chloride or magnesium sulfate and occasional shaking. Filter or decant the product into a dry 10mL
flask.
Equip the flask for simple distillation as shown in figure 3, but do not run water through the
condenser. Heat the flask and collect the fraction distilling at about 200-210 °C. Do not overheat the
residue or boil the flask to dryness, as the di- and polynitro compounds may decompose explosively.
Do not inhale the toxic nitrobenzene or spill it on your skin. Any spills should be removed with
alcohol and washed immediately with warm water and soap.
Place in the 100 mL flask 3.5 mL of nitrobenzene and 7.5 g of granular tin. Equip the flask with a
condenser as shown in figure 1. Measure 16.5 mL of concentrated hydrochloric acid, which is to be
added in approximately 3 mL portions. Add the first portion of acid through the condenser and swirl
thoroughly until the mixture begins to boil. If the mixture is reluctant to boil, it may be warmed; if it
becomes too vigorous it should be cooled. In a few minutes when the reaction subsides, add another
portion of acid and repeat the procedure. Continue until all the acid has been added.
Reflux the mixture for 40 minutes to complete the reaction. Cool the flask to below room
temperature by immersion in an ice bath. With the ice bath in place, add 12.5 g of sodium hydroxide
dissolved in 25 mL of water, a few mL at a time, with thorough mixing to avoid localized
superheating. Remove the condenser and equip the flask for steam distillation as shown in figure 5,
but with a stopper in place of the thermometer. Begin the generation or admission of steam when
the reaction mixture is at a steady boil. Collect 20-30 mL of the distillate. This should represent an
excess of water collected beyond the point of disappearance of turbidity.
Saturate the aqueous layer by shaking with 6 g of salt. Extract the aniline from the mixture with three
successive 10 ml portions of ether. Dry the combined ether extracts with 3-4 g of solid sodium
hydroxide or anhydrous potassium carbonate.
Assemble the apparatus for simultaneous addition and distillation (figure 6) with the cleaned and
dried separatory funnel, a 10 mL distillation flask, and the 50 mL flask as the receiver in a cold bath.
Place a rubber tube which will reach to the floor on the outlet arm of the vacuum adapter. Decant or
filter the dry ether solution into the separatory funnel. Also rinse the drying agent with a small
portion of ether and add this ether to the funnel. Close the funnel with a drying tube or stopper
slightly ajar. Place a boiling stone in the distillation flask, and add 4-6 mL of the ether solution.
Carefully distill the ether using a boiling water bath. The ether solution is added to the distillation
flask at such a rate that the original volume is approximately maintained. When no more material
distills under 100 °C, the apparatus is allowed to drain and cool to approximately room temperature.
Then add a new boiling stone and rearrange the apparatus for simple distillation (figure 3) but with a
standard taper flask as the receiver. The fraction distilling between 176-186 °C is collected in the
receiver. No water is needed in the condenser for this distillation.
Place 12 mL of water and a boiling stone into a 50 mL flask. Add (caution!) with cooling, 6 mL of
concentrated sulfuric acid. When the flask no longer feels warm, cautiously add 6 mL of 1-propanol.
The apparatus is assembled as shown in figure 6 except that the condenser-fractionating column is
placed between the Claisen adapter and the distillation head and that the receiver, surrounded by an
ice water bath, is used to collect the product. In the separatory funnel is placed 8.5 g of sodium
dichromate dihydrate dissolved in 10 mL of water.
Heat the mixture in the flask until the condensate reaches well into the vertical condenser. Then
remove from the heat source and add the dichromate solution at a moderate rate. Control the rate so
that, with only occasional heating, the reaction is maintained and presently propanal (b.p. 49-50 °C)
will distill. Collect the product in the range of 40-70 °C. If the temperature rises above 65 °C, reduce
the rate of addition and heating so that distillation is just barely continued. Once the addition is
completed and the reaction subsides, heat the mixture cautiously to distill any remaining aldehyde. If
the aldehyde is distilled as it is formed and fractionated carefully as it is distilled, a good yield of
relatively pure product may be obtained.
Redistill the product if there is doubt as to its purity.
Place 1.2 g of red phosphorous and 7.2 mL of 1-propanol in a 25 mL flask and equip as in figure 1, but
with an outlet adapter at the top of the condenser. Attach in this adapter a piece of 6 mm tubing
with two right angle bends. Place a test tube containing water around the outside end of this tube so
that the water almost touches the tube. This will serve as a trap for hydrogen iodide. Sodium
carbonate solution may be used in place of the water.
Divide 12 g of iodine into five to eight portions and roll a paper powder funnel. Add one portion by
briefly replacing the outlet adapter with the paper funnel and then return the adapter. Warm and
swirl to start the reaction. Continue with the addition in this manner, allowing 2-3 minutes between
each portion. When the addition is complete, gradually bring the mixture to a boil and reflux for 3545 minutes.
Rearrange the apparatus as shown in figure 3 but for the receiver use a test tube containing 6 ml of
2% sodium hydroxide. Put a boiling stone in the flask and distill all the iodide into this receiver, but
do not boil to dryness. Mix, then decant, some of the aqueous layer from the receiver, add 5 mL of
water, and separate in the funnel. Thoroughly dry the iodide (anhydrous calcium chloride is good)
and redistill the iodide in the apparatus shown in figure 3 with a 10mL distillation flask. Collect the
n-propyl iodide between 95-105 °C in a receiver. The glassware may be cleaned with sulfite or bisulfite
solution.
Place in a 50 mL round bottom flask 7g of adipic acid, 12 mL of ethanol (95%, density = .8025g/mL), 15
mL of benzene or toluene, and 5-8 drops of concentrated sulfuric acid. Before assembling the
apparatus shown in figure 7, prepare the special distillation receiver. Close the small tube with a piece
of rubber and a clamp. Determine the amount of water which should be collected from all sources.
Using this volume, calibrate the phase separator approximately and then drain it thoroughly.
Assemble the apparatus and reflux the mixture briskly, draining water into a graduate if necessary.
Discontinue the reflux when no more water appears to be collected or after the phase separator has
been functioning for an hour or more. Decant the cooled mixture into 25 mL of 10% sodium
carbonate and a drop of Congo Red and separate the layers. Shake the non-aqueous layer with a little
drying agent and filter this layer into a 25 mL flask containing a boiling stone. If the volume exceeds
18-20 mL, use the technique of simultaneous addition and distillation as illustrated in the preparation
of aniline. Distill all the material boiling under 110 °C (figure 3 or 4). Remove the source of heat and
attach the outlet of the vacuum adapter to a backup trap and thence to a water aspirator. Introduce a
fresh boiling stone and assemble the apparatus shown in figure 3 or figure 5 with a flask or a
graduated receiver to collect the product. The product should be collected in the range 120-140 °C at
reduced pressure. Many acids, propionic acid and higher homologs, may be used though fractional
distillation may be required. A variety of alcohol may be used, but if the alcohol is not appreciably
soluble in water, just less than the stoichiometric amount of alcohol should be used.
Caution: There should be no flames on the benches or in the working area where this experiment is
performed. It is essential that the equipment be scrupulously dry and the reagents for the reactions be
pure and dried.
Place a small crystal of iodine and 2 g of magnesium turnings in a 100 mL flask. Brush the flask with a
low flame to just barely volatilize a little iodine. When the flask has cooled (no flames beyond this
point), add 5 mL of absolute ether and assemble the apparatus shown in figure 2. In the funnel, place
a mixture of 9 mL of pure n-butyl-bromide and 20 mL of absolute ether. The funnel and the
condenser should be closed with drying tubes. Prepare a hot water bath (heated elsewhere) and a
cold water bath to be used as needed in controlling the reaction. Run in 2-5 mL of the halide ether
mixture, and if the reaction does not start in a few moments, heat the mixture to a boil with the hot
water bath. Withdraw the bath and determine if the reaction has begun. This process may be
repeated. If after five minutes there is no sign of reaction, add another crystal of iodine or gently
crush some of the turnings with a dry stirring rod or add a little Grignard reagent from an external
preparation. When the reaction is definitely started, add the rest of the halide-ether mixture, slowly
with swirling so as to maintain a moderate rate of reaction. Complete the reaction by refluxing the
mixture 15-20 minutes after the addition is complete.
Cool the mixture as completely as possible by placing an ice bath around the flask, and place a
mixture of 6.2 mL of dry acetone and 10 mL of absolute ether in a separatory funnel. Add the mixture
very gradually with swirling and cooling. Allow the mixture to come to room temperature and stand
for 15-30 minutes (or overnight) with occasional swirling. Pour the contents of the flask into a mixture
of 14 mL of dilute hydrochloric acid and 20 g of cracked ice in a 250 mL beaker located in a hood.
Wash the contents of the flask into the beaker with the resulting aqueous layer with three 10 mL
portions of ordinary ether which have been used to rinse the flask and beaker. Combine the ether
extracts and the ether layer and wash this with a mixture of 5 mL of 5% sodium bisulfite and 15 mL of
10% sodium carbonate. Then wash the ether solution with 10 mL of water or saturated salt solution.
Dry the ether solution in a clean dry Erlenmeyer flask with 2-4 g of anhydrous potassium carbonate or
magnesium sulfate. Allow the drying process to continue for at least 2 hours, or preferably overnight,
after some initial swirling. Follow the directions for the distillation of an ether mixture given in the
preparation of aniline. However, collect the product of this experiment in the range 135-145 °C. If a
sizable fraction collects at a temperature intermediate between the ether and the alcohol, dry this
fraction and redistill or mix it with 2-3 mL of benzene and fractionate.
Components for 14/20 KEM-KIT®
ItemNumber
Des cription
Kit Qty .
273410-0000
Bleed Adapter
1
273750-0000
Claisen Adapter
1
274950-0000
Connecting Adapter
1
275410-1420
Outlet Adapter
1
276400-0000
Vacuum Adapter
1
282550-0000
Condenser, West
1
286820-0110
Distillation Column
1
294000-0025
Flask, 25 mL
1
294000-0050
Flask, 50 mL
1
294000-0100
Flask, 100 mL
1
294000-0250
Flask, 250 mL
1
294000-0500
Flask, 500 mL
1
298281-0125
Funnel, 125 mL, PTFE
1
850500-1420
Stopper
1
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