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Schlenk Tube Technique( Supervised by Ph. D. Masato Tanaka )2018 spring edition© : All Rights are Reserved by SUGIYAMA-GEN Co.,Ltd.

Schlenk Tube Technique
Original work and supervision
Masato TANAKA, Ph.D. Professor
Tokyo Institute of Technology
Chemical Resources Laboratory
1. Introduction
Experimental methods in inert atmospheres have become indispensable not only ininorganic and organometallic chemistry, but also in synthetic organic chemistry andmaterials science. The number of glovebox-equipped laboratories has risen in recent years,
allowing experiments using this equipment to be conducted.
The glovebox method is incredibly convenient, as it allows experiments to be conductedunder controlled internal conditions, with inert gases from which oxygen and moisture havebeen removed circulating throughout the box. Frankly however, not only are the proceduresfor introducing reagents and glasswares to the glovebox main body and antechamber, etc.,
complicated, and time-consuming. In addition, the operator’s face can become itchy at a
crucial point in the procedure.
In order to use the glovebox method on a regular basis, laboratories must have as many
gloveboxes as the number of workers and pay high prices for the equipment itself andrunning costs. Furthermore, there is no hope for a sufficient number of the equipment
installed, where the space is highly limited. Under such circumstances, the Schlenktube method remains fundamental in experiments using oxygen- and moisture-sensitive
substances, and especially in experiments handling organometallic compounds.

1

A glass apparatus invented by Dr. W. Schlenk is used for the Schlenk method. Thisapparatus is called the Schlenk tube and has been developed into a wide variety of moreconvenient apparatuses by subsequent researchers and glass craftsmen. To do a good job in
any field, whether it is science, art, or sports, it is essential to select, master the use of, andapply the proper tools.
Likewise, to do a good job using the Schlenk method, it is essential to select, masterthe use of, and apply the proper tools. This manual will explain the manipulation of theSchlenk tube and the basic apparatus that can be used with it.
Note that in the following explanations, all manipulations under inert gas are given with
N2 gas, but argon is used in exactly the same way.

FilterSchlenk Tube
A2 typeU-1012 : 100mL“Non-operational
state”
No color

Schlenk TubeB typeU-1013 : 30mL
U-1014 : 50mL

Schlenk Tube
C typeU-1015 : 30mL
U-1016 : 50mL

“Evacuation State”
Blue“N2 gas filling state”
Orange02
Text will be color-coded in the following way to allow easier understanding:• "Non-operational state” prior to start of the experiment – No color• “Evacuated state” with vacuum pump – Blue
• “N2 gas filled state” – Orange
More comprehensive explanation on manipulations under inert gas is found in thereferences given below. *Procedures are fundamentally identical, but some differences may arise depending on
individual cases (and the researcher’s preferences).
In addition, by understanding, mastering and applying various techniques, readers can
expect to see more efficient progress in research and development.
*Note: D.F Shriver, translated by: Yoshito TAKEUCHI, Hitoshi MIKUNI, and Shūji
TOMODA, “Manipulation of Air Sensitive Compounds", Hirokawa Shoten, 1972. 12;
Akio Yamamoto, “Organometallic Chemistry”, Shoˉkaboˉ Publishing, 1982, p.178.

22. Schlenk Cock
The reader is likely be already familiar with the common Schlenk Tube (referred to below
as Tube ).
The Schlenk Cock (referred to below as Cock ) used here is a Stopcock made of glass andis an indispensable component for simple, rapid, and reliable operations in a perfect inert
atmosphere. The structure and operation of the Stopcocks are described below. In the
Schlenk method, the atmosphere inside the Tube or related vessels is replaced with
N2 gas by repeated evacuation and introduction of N2 gas. The Cock is used to selectbetween the vacuum and N2 gas.Its difference from the T-shaped-3-way Stopcock isdisplayed in 03 and 04 .
aaa
Pocket

03-1

03-2

c

c

b

b

c
a
a
PocketPocket

03-3

03-4

c

b

c

b

03

b

1. As shown in 03-1 , with the T-shaped-3-way Stopcock, all 3 directions (a, b, and c), canbe connected at the same time. In this case, evacuation and N2 gas input can occur at thesame time.
2. Moreover, as shown in 03-2 , when a⇔c is connected and N2 gas is passed through, a
pocket (dead space) arises in the flow path. Because it is impossible to completely remove
the air (oxygen) in the pocket by simply passing N2 gas, air contamination may occur.
3. In contrast, with the Cock, only 2 direction circuits, A⇔C / B⇔C / A⇔B are possible
since the Cock is not a three way Stopcock, but comprises 3 sets of 2-way Stopcocks.
Accordingly, there is no pocket (dead space). Even when the stopper is removed forsampling and addition of chemicals during the reaction. These operations can be carriedout without air contamination by introducing N2 gas through the Cock.

3

Accordingly, use of the Cock is preferable over the T-shaped-3-way Stopcock for the
Schlenk glass apparatus.
It is possible to replace the vacuum and N2 gas lines connected to the branch pipe A andleg pipe B of the Cock depending on the handling and ease of operation of equipment
concurrently in use, but in this manual, the explanations will generally follow theconfiguration illustrated in 04 , where branch pipe A is connected to the vacuum line andleg pipe B to the N2 gas line with branch pipe C fused to the body of the apparatus.
In this case, the connections and functions of each circuit are as follows:
A. Turn the Hollow Glass Plug (reffered to below as HG Plug ) to circuit A⇔C to evacuate
the apparatus.
B. Turn the HG Plug to circuit B⇔C to introduce N2 gas into the apparatus.
C. A
 fter the gas has been displaced completely by alternating between evacuation andintroduction of N2 gas, remove the rubber tube from A and turn HG Plug to circuitA⇔B to isolate it from the outside.*ProtrusionN
HG Plug

To the vacuum
manifold

M

A

M
A

A⇔C circuit

C

C

Q

A⇔C circuit B
N

To the body of
the apparatus

M

B

A

Leg pipe

04

ProtrusionC

HG Plug
M

A

Q

B⇔C circuit

B

Branch pipe
N
M

C

C
To the body of
the apparatus

B

Q

To the N2 gas manifold

4A⇔B circuit BA* When the HG Plug has been turned to circuit B⇔C , the pressure inside the vessel isslightly higher than that outside (vide infra). Hence, when you turn the HG Plug to circuitA⇔B , air does not infiltrate from outside, unless you turn it too slowly. Note that theprocedure mentioned above in A, B and C is not the easiest way to replace air by nitrogen.
The easiest way is shown in 10 ,if the vessel is empty.
3. Transparent and opaque joints
The ground tapered joint of the glass apparatus joins the male joint (referred to below as
the Plug) to the female joint (referred to below as the Socket) 05 . Typically, the joints areopaque, but transparent ones are standard for joints in the Sugiyama-gen glass
apparatus.
(male joint)

Universal ground joint
Diameter

15/25

Specifications

29/32

15：25mm

Diameter : Length

29：32mm

Length(female joint)05

スギヤマゲンTransparent joints are precisely polished and have high airtightness. As such, they canfrequently be used without greasing. However, they do not allow maintenance of a precise
level of pressurization and decompression over an extended time period. Even very fineemery powder is coarser than gas, so gas will leak through the bumps on the groundsurface. To tightly seal the joint portion, the bumps on the ground surface must be filledwith a thin coating of grease, which must stay put.
However, grease tends to be lost from the joints when the vessel is evacuated because theground scratches in transparent joints are very shallow.
So, when putting the Schlenk apparatuses together, using a transparent joint, it isimportant that the other joint must be opaque, and that the opaque joint must be thinly
coated with grease to fill the joint surface scratches, and to ensure the grease be stayed on .
Do not put too much grease; the excess grease oozes out, contaminating the sample, ending
up with unsuccessful recrystallization.
So how do you determine the right amount of grease? To get the right amount of grease,
put Plug and Socket using a very thin layer of grease, then press lightly and turn. If theglass at the jointing portion appears transparent without streaks, it is OK. This is just an
abstract explanation. To gain more realistic explanation, do it yourself.
To become skilled in the procedure, the reader must master this technique through repeated practice.

5

4. Preventing Grease Contamination
What can be done to prevent contamination of the solution in the Tube with the grease
applied to prevent leaks from the stopper and allow smooth HG Plug rotating operation ?
1. It may be effective, for example, to use a greaseless-type screw valve in place of a Cock
However, because greaseless screw valves can only function as 2-way stopcock, it isnecessary to use a glovebox or attach the Cock separately to the vacuum and N2 gaslines to get a perfect inert atmosphere.
Seal the gap tightly after expelling the air from the gap
where the cap had been suspended with N2 gas flow.
06-1

06-2

When you haveclosed thestopper06

PocketN2

3Way Stopcocked
Connector type B
U-1038

N2

A
C

C

C
B
Schlenk tube B typeU-1013：30mL
U-1014：50mL

A

A

B
Schlenk tube C typeU-1015：30mL
U-1016：50mL

B
Schlenk tube C typeU-1015：30mL
U-1016：50mL

2. Grease enters from the Cock and stopper joint, but contamination from the stopper ismore serious. In order to avoid the contamination from the stopper, use Schlenk tube Ctype with a male joint and female stopper. The point is that, when the stopper is placed,
there can be a pocket, which prevents grease or a solution of grease from flowing down
into the vessel, as shown in 06-2 . In order to allow for pocket formation when the
covering stopper is closed, the Socket of the stopper is made to be slightly shorter thanthe length of the Tube’s Plug . It is also designed to minimize the ceiling space when the
stopper is closed (approximately 2mm).
3. Low boiling solvents in the Tube may condense in the pockets. If this can happen, usea stopper attached with stopcock (⇒U-1038). When condensation has indeed happened,
insert a syringe needle to the pocket to remove the condensate before it overflows into theTube. This requires a high level of skill.

6

5. Points to Consider When Closing the Stopper
1. For the Plug stopper such as those shown in 06-1 Tube, suspend the stopper for sometime with a finger. While allowing the micro pressurized (0.3-0.4atm) N2 gas to escapefrom the small gap thus created, extrude the remaining air, close the stopper when it has
been completely flushed, thus closing the stopper while blocking air contamination.
2. F or the Socket stopper ( lid cover ) such as those shown in the 06-2 Tube, suspend thestopper for some time with a finger. While allowing the micro pressurized (0.3-0.4atm) N2
gas to escape from the small gap thus created, extrude the remaining air from thestopper, flush it out completely, and close the stopper, blocking air contamination.
3. Connect black rubber tube J to the Tube shown in 07 . When black rubber short tube K,
attached to the part H of the U-1003 type Bubbler containing a small amount of liquidparaffin (referred to below as Bubl) is closed with pinchcock L, either the Plug or the
Socket can be used to lightly cover the Tube opening. The stopper will float up due tothe micro pressurized (0.3-0.4atm) N2 gas. Extrude the remaining air from the small gap
created to close the stopper while blocking air contamination.
4. E
 ven when the short rubber tube K attached to the part H is left open, rather than closedwith the pinchcock L, “super” micro pressurization corresponding to the liquid paraffinheight is maintained, allowing the flow of N2 gas through the gap made with fingers.

N2 gas line (approximately 0.3-0.4atm)

V11
Thick rubber tube
Approximately 80mm

N2

Seal the gap tightly after expelling the airfrom the gap where the cap had beensuspended with N2 gas.
M

D

Evacuation

H
K
I
J

A

C

L
Black rubber tube
Approximately 100mm
lengthR
BubblerA⇔C circuit
B

Vacuumrubbertube

Q
Schlenk tube

Black rubber tube: Approximately 600mm length

707

6. How to Avoid Over-greasing
Contamination of the sample with grease must be minimized, especially when
crystallization is desired and when handling silicon compounds.
What is an efficient way to precisely maintain decompression and pressurization without
using any grease ?
In this case, glass apparatuses fitted with finely ground transparent Plugs and Sockets
are used. However, this method does not allow for the maintenance of high air tightness.
Hermetic tightness is maintained by sealing with white Teflon tape instead of using grease.
Specifically, wipe the Plug well, apply the Teflon tape to it, and press on that end with yourleft finger (if right-handed). Wind around once while pulling on the tape with your righthand. Wind around a second time and pull tightly to tear the tape off. *This Plug is fitted to the Socket. Pushing strongly while turning in the direction the tape
was wrapped will result in a hermetic seal.
Do not apply too much force, or you will break the glass. For you safety, work with gloves.
* Do not cut Teflon tape with scissors.
When scissors are used, no matter how hard you push the Plug to the Socket, level
differences in the thickness of the parts where the tape overlaps remain, allowing
leaks from the gaps and inhibiting air tightness.
It is important to wrap the tape around the Plug for about one-and-a-half turns andtear the tape off at an angle as right as possible.
A highly hermetic seal can be obtained by pressing down strongly on the torn portionof the tape which was stretched thin. This allows the level difference to disappear.
It is important to stretch while wrapping to ensure the two ends of the tape ( madefibrous through tearing ) do not overlap. It takes some getting used to, but skill inthese procedures can only be obtained through repeated practices.
This way of sealing is not only limited to the operations of the Tube and Schlenk flask,
but also can be applied to the reflux condenser, dropping funnel, 3-way Stopcock anda variety of other apparatuses (excluding the Stopcock portion). It allows for high air
tightness without the use of grease. Though the Teflon Stopcock-Plug appears useful as
it saves one the trouble of having to wash the grease from the apparatus after use, it does
not allow for high air tightness regardless of how much the inelastic Teflon Cockplug istightened. Accordingly, apart from typical organic synthesis using the Grignard reagent,
Teflon Stopcocks should not be used in procedures using those materials as immediately
decompose in oxygen.

87. Nitrogen Line Layout
Typical lab bench layout when the Schlenk tube technique is frequently used is illustrated
in 09 . For example, in settings such as university laboratories, where a large number ofstudents carry out the similar procedures at the same time, a large number of nitrogen
cylinders cannot be set up at the same time due to High Pressure Gas Safety Act
regulations.
1. T ypically, thick metal piping is laid out across the entire room from a single N 2cylinder. This is divided into a number of N2 gas line series (in the figure, these areseries 1, 2, and 3).
2. The 2nd pressure of nitrogen in the piping depends on the number of series, but thepressure-reducing valve is adjusted to keep the pressure around 5 atm.
3. The following devices are connected to the N2 gas lines of each series in the specified
order: gas pressure regulator⇒flow meter (float-type ones are easier to read) N2 gasoutlet (It is convenient to have around 5-6 outlets every 15-25 cm in each series
although only 3 outlets are shown in 09 ). The gas pressure regulator is adjusted tomaintain a micro pressure of around 0.3-0.4 atm. Do not change this pressure without
permission.
Beware of making the pressure higher: it may make the attached stoppers, dropping
funnels and other glasswares attached may fly off and break.
Series 1N2 gas line
(approximately 5.0atm)

Series 2

Series 3
Metal piping

V11

V12

D

D

Vacuum rubber tube

I

K

K

V13
L

H

I

R2

N2 gas line
(approximately 0.3-0.4atm)

D
R3

09

U-1160N2/Vacuum
selector
Vacuum rubber tube

II

M
A
Q

U-2008trap C typeC
B
A⇔C circuit
VP
Vacuum rubber tube
Vacuum pumpN2 tank

9

Liquid nitrogencold trap

McLeodvacuum gauge

A gas pressure regulator installed before the flow meter is set for each series in 09 , but
installation of one regulator for every 3 or 4 piping series is acceptable. However, it isbest to set a flow meter to each series individually.
4. Typically the N2 gas outlet V12 and V13 (the use of metal valves make it easier toadjust the flow) is connected to Bubl R2, R3, as exemplified by the “Series 3” piping in
09 .
5. Installation of a vacuum pump for each N2 gas line series makes the experimental
operations easier and convenient. But if a number of vacuum sources are often required,install vacuum lines equipped with glass Stopcock or metal valves.
6. In the “series 3” piping example in 09 , outlet V11 on the left end of the N2 gas line isconnected to the N2/vacuum selector (referred to below as “selector”; for details, see 14 .
The upper 3-way Stopcock shown in 09 works as a valve for switching between theevacuation and N2 gas introduction and the lower 2-way Stopcock works as an opening
and closing valve. Figure 10 shows operation tips for the switch. Below is provided an
explanation with reference to the figure. Further procedure that follows is exemplified byusing selector 14R .
N2 gas line (approximately 0.3-0.4atm)
V11

a

10

b

I

a

b

II

Plug

c

c

7. C
 onnect V11 of the nitrogen line
and leg pipe a of the selector using
evacuationpressure resistant rubber
tubing. Likewise the leg pipe b andvacuum valve V21 are connectedusing evacuation-pressure resistantrubber tubing.
8. Then, connect the leg pipe c of theselector and the side pipe A of Tube
with evacuation-pressure resistantrubber tubing.
T u r n t h e H G P l u g M t o wa r d s
circuit A⇔C .
9. T urn the HG Plug of the selector
from pattern I to II to evacuate theTube.
10.T urn the HG Plug of the selector
back to pattern I. Now N 2 gas is
introduced to Tube from V11 .
11.Repeat 9. and 10. several times ; thegas in the Tube will be turned into
pure N2.
Note that you can follow the sameprocedure even when Tube contains
non-volatile solid.
However, you should take account ofM
AA⇔C circuit
C
B
Q

10-1
V21
Vacuum line

cautions given in 15 5.

10Nitrogen/Vacuum Line Type I: “Straight bore two way Stopcock type”
This type of single-column glass line is inconvenient, as it can be used only for the vacuum
manifold or the N2 gas manifold , but not both. However, because it is reasonably priced,
it is suitable for student training.
Depending on the purpose, use either the a) single-column line × 1 unit or b) singlecolumn line × 2 units (for nitrogen and vacuum).
Even when you use one unit of the single-column, place a selector as shown in 09 to makethe line more convenient.

N2 gas line (approximately 0.3-0.4atm)
Stopcock
V11

Flowmeter

V12

V13

V14

Nitrogen / Vacuum Line:“Line-cock type”
U-1171 3 tandem typeU-1172 2 tandem type

Regulator
N2 gasLeak cockEvacuation

11-1

U-2008trap C type

VP

N2 tank

11

Vacuum pump

11

Liquid nitrogencold trap

McLeodvacuum gauge

Nitrogen/Vacuum Line Type II: “Three Way Stopcock with Double Oblique Hollow
Glass Plug and Vacuum Chamber type”
With this type of double-column line, one can be used for the vacuum manifold and theother for the N2 gas manifold . With a single manipulation of the Stopcock-Plug,continuous switching between evacuation and N2 gas input can be conducted from any
nozzle.
Do not apply too much grease for smooth operation of Stopcock-Plug.

N2 gas line (approximately 0.3-0.4atm)

V11

V12

V13

V14

Stopper

Nitrogen / Vacuum Line
“Top-joint cock type”
U-1075 3 tandem typeU-1076 5 tandem type

Flowmeter

N2 gasLeak
Regulator

Evacuation

12-1

180º turnU-2008trap C type

VP

Vacuum pumpLiquid nitrogencold trap

McLeodvacuum gauge

1212

N2 tankNitrogen/Vacuum Line Type III: “Greaseless type Screw Valve with PTFE Plug ”
If grease is objectionable at any cost, the greaseless-type Screw Valve can be used, as
shown in 13-1 . However, these valves function only as 2-way Stopcocks. As such, theconvenience of being able to continuously switch between evacuation and N2 gas input
from any nozzle with a single manipulation of the Stopcock, as with the oblique bore
three way Stopcock must be sacrificed.

N2N2 gas line (approximately 0.3-0.4atm)

V11

V12

V13

V14

N2 gasNitrogen / Vacuum Line
“Top-joint cock type”
U-1075 3 tandem typeU-1076 5 tandem type

Flowmeter
Vacuumpump

Regulator

13-1

Evacuation

Leak

U-2008trap C type

VP

13

Vacuum pumpLiquid nitrogencold trap

13

McLeodvacuum gauge

N2 tank

8. Three Types of Selectors
Three types of selectors to displace the atmosphere from air to N2 gas are introduced in
14Q, 14R and 14S . Especially 14R and 14S comprises 3 sets of 2-way Stopcock just like
Cock does shown in 4 . Select one as you like it.

14Q

N2 gas
a

a

a

c

c

c

b

b

b

ClosedEvacuation

EvacuationddEvacuationdTube
N2 gas14Rab

Evacuation

a

a

b

Evacuationb

Closed

c

c

c

Tube

14S

Tube
N2 gasabb

N2 gasaab

Closedccc

Evacuation

149. N2 Gas Substitution in Empty Vessels or Solid-containing Vessels
The method displayed in 10 is commonly used, but the same effect can be obtained bymanipulating the Cock of the Tube. The following is an explanation with reference to 15
and also 07
Repeat about 3 times
Evacuation
M

M

A

C

C

B⇔C circuit
Q

AA⇔C circuit
B

Q

B

N2 g a s
introduction

15

1. Put the evacuation pressure-resistant rubber tube (referred to below as vacuum rubbertube) extended from the vacuum valve to branch pipe A of the Cock of Tube Q. Put on
the black rubber tube from the N2 gas outlet to leg pipe B.
2. Turn Hollow Glass Plug( or HG Plug ) stopper towards circuit A⇔C and evacuate Q.
3. T urn HG Plug M towards circuit B⇔C to introduce N2 gas into Q.
4. By switching between 2.: Evacuation and 3.: N2 gas introduction 3 times, the inside of
Q becomes a near-perfect N2 gas atmosphere.
This takes only 30 seconds at most.
5. I t's OK to follow exactly the same procedures with a solid in the vessel. However,particularly when the solid is a micro-powder, carefully and slowly manipulate the HG
Plug to ensure that the solid is not blown up by the flow of the incoming N2 gas or
sucked into the pump upon evacuation.
…Here, lets return to 07 to explain what happens when the Bubl is used.
6. Put on the vacuum rubber tube extended from vacuum valve V21 on branch pipe Aof the Cock, turn M towards circuit A⇔C , and evacuate Q.
7. The black rubber tube J extended from I of Bubl is connected to branch pipe B of
the Cock. Turn HG Plug M towards circuit B⇔C and introduce N2 gas into Q.
8. By switching between 6.: Evacuation and 7.: N2 gas introduction 3 times, the inside of
Q becomes a near-perfect N2 gas atmosphere.

1510. Bubbler Operation
As an example, we will describe the operation of the bubbler (U-1003) using in
combination with Schlenk round-bottom flasks.
Above all, the most unique feature of this device is that it has a glass disk F, which acts as“valve” or “shutter” to prevent the counterflow of the liquid paraffin.
Operation is straightforward and effective.

N2 gas line (approximately 0.3-0.4atm)
V11
Thick rubber tube
Approximately 80mm
lengthBlack rubber tube
Approximately 100mm
length

K

D

L

H

16

k
lac

bb

ru

e

I

ub

t
er

R

Supply Gas
Pressure adjusting
Bubbler
U-1903U-1003
bubblerC type

B

J

E

E

h

F

F

G
16-1
16-2

Q
Tube

E

f

g

LiquidparaﬃneLiquid paraﬃn

F

Bubbling

d

16-3

Q
Tube

c
Black rubber tubeba

1. Arrangement
1. An N2 gas line gas pressure is set at 0.3 ~ 0.4atm.
2. An N2 gas outlet V11 and Bubl is connected by a short vacuum rubber tube D and a
black rubber tube J (ca. 600 mm) is connected to branch pipe I.

16

*Note: When not conducting an experiment or when there is nothing connected to the endof J, outside air can enter into J and result in oxygen adsorption by the inner walls of the
tube. In order to avoid this situation, do not leave the tip of J open.
3. Put a short (100mm) black rubber tube on Bubl branch pipe H. Place pinch cock L
on H, so that it can be immediately opened and closed depending on need.
4. Inject liquid paraffin into Bubl in advance. The right amount to inject is slightly more(≈2ml) than the Inner volume of the inner tube G below E.
5. Evacuate Tube Q.
At this point, sudden decompression of the inside of the flask and bubbler leads
instantaneous movement of the disk F up to the stopper E 16-1 . This movement prevents
the infiltration of liquid paraffin instantaneously, which in turn prevents the influx of
external air from H. Time required for evacuation depends on the size of the vessel, but acouple ~10 seconds is enough. If the need arises, it is advisable to check the pressure by a
McLead vacuum gauge situated between the vacuum line and vacuum pump.
6. Introduce N2 gas into Q. N2 gas is introduced though D→I→J and once the Schlenk
flask is filled, change direction and flow through to depress F 16-2 and flow out from H
with bubbling through the liquid paraffin. Even though L has been removed and K open,
the inside of the apparatus is maintained at the “super” micro pressurization
corresponding to the distance between the bottom of G and the surface of the liquidparaffin (=liquid paraffin column). This helps minimize the influx of external air.
*Note 2: Because the inside of the apparatus is still in a micro pressurized state (0.30.4atm), use a stainless spring or a thick rubber band to tightly shut middle stopper M toprevent it from lifting and flying off.
2. Supply Gas Pressure adjusting Bubbler
Shown in the former page 16-3 is another type of Bubl U-1903, which is utterly different infunction and application from U-1003.
1. It is applicable in case of flowing a certain gas from branch pipe a to b.
By rotating the cap h, restoring strength of the spring g can be adjusted to desired extent,
so as to previously control the supply gas pressure in an expected degrees.
Inject liquid paraffin into the well d in advance. The right amount to inject is slightly
more than the Inner volume of the inner tube. For detail see the illustration of 16-3 .
2. If the supply gas should carelessly rush flowing from the branch pipe a to b, the excessivegas pressure push up the oppressing edge d of the lifter e from the semi-ball type jointc, making gap between c and d. The excessive gas expels through this gap with bubbling
through the liquid paraffin out of the leak pipe f, keeping the previously controlled gas
pressure degrees.
3. In the meantime, you should again check and adjust the Gas Pressure Regulator ⇒the Flow Meter, recovering into normal conditions.

1711. Degassing of Solvents and Reagents
Solvents and reagents used in an N2 gas atmosphere must have been removed dissolved
oxygen beforehand. When using a large amount of reaction solvent, dissolved oxygen isremoved by refluxing under a stream of N2 gas. In a small scale experiment, however,operate in accordance with the figure below for degassing.

Evacuation

Freezing
M

Evacuation

N

M

A

A
C

Q

C

A⇔C circuit

B

Q

SeptumB

A⇔B circuit
SeptumTo evacuate, turn plug M
toward circuit AC in aliquid nitrogen bath.

To freeze, turn plug M
toward circuit AB and
immerse in a liquid
nitrogen bath.

18
Melting

DegassingA⇔B circuitA
M

To melt, turn plug M
toward circuit AB
and remove fromN
liquid nitrogen bath.

B
C
Q

SeptumA⇔B circuit

As the material
melts, the dissolved
oxygen bubbles and N
is transferred into
the gas phase.

M

A

B
C
Q

SeptumAs in the above figure, repeat the Freezing ⇒ Evacuation ⇒ Melting leading to bubbling(Degassing) procedures 3 times. After checking that there is no effervescence at themelting-degassing stage and all dissolved oxygen appears to have been removed, remove thevacuum rubber tube from A, put a black rubber tube from the nitrogen line to A, remove
the septum attached to B, switch HG Plug M to flow N2 gas through circuit A⇔B to I,
and switch M to circuit A⇔C to introduce N2 gas into Q. Note that degassing can be moreeasily carried out by using the selector. 10
A solvent with dissolved oxygen completely removed can be obtained in this way.
*Note: In degassing water, when the water turns to ice, its volume increases. Accordingly it
is safer to use a round-bottom vessel than a cylindrical Tube. Even in this case, it is safer
to freeze onto the vessel wall by agitating its contents all the time. When using a cylindrical
vessel, agitation of the vessel contents while the vessel is immersed in liquid nitrogen mustnot be neglected. Note well that the vessel will break otherwise unless you agitate.

18

12. Evaporation of the Solvent in the Schlenk Reaction Vessel
1. When evaporating solvent in accordance with 10
1. Connect branch pipe A and the selector leg pipe D with the vacuum rubber tube.Turn the
HG Plug M of the Tube’s Cock from A⇔B circuit to A⇔C .
*Note 1: You are going to evaporate a solvent, so ensure that the cold trap is placed before
the vacuum pump.
2. Open vacuum valve V21 and while stirring the reaction solution inside the Tube witha magnetic stirrer, gradually move the switch over to setting II, and evaporate thesolvent under reduced pressure.
*Note 2: When evaporating under a reduced pressure, the temperature of the solution
decreases due to the solvent's latent heat of vaporization. To facilitate the evaporation
process, sustain the temperature through immersion of Tube in a water bath, heatingwith a heater when needed, etc.
*Note 3: By continuing the evaporation of the cold solution without sustaining thetemperature, the solution itself may foam under a reduced pressure and flow out from Q.
To avoid this problem, in addition to sustaining the temperature, adjust the HG Plug M,
the vacuum line metal valve V21, etc., to set the most appropriately reduced pressure,while keeping close watch over the state of evaporation.
3. After the evaporation has progressed to a desired extent, change the switch to setting I
to introduce N2 gas into the Tube from V11.
*Note 4: When the amount of the solution is too large, it may overflow. To prevent such asituation, evaporate after transferring excess solution to a separate tube. After the firstaliquot has been evaporated, add another small aliquot and evaporate it. It is advisable tocarry out this procedure several times.
2. When evaporating solvent in accordance with layout 16 .
1. Put vacuum rubber tube on from vacuum valve V21 to branch pipe A of the Cockof the Schlenk round-bottom flask Q. Also connect branch pipe B of Q’s Cock andbranch pipe I of the Bubl with the black rubber tube.
2. While stirring the solution in Q with a magnetic stirrer, gradually turn the middle
stopper M to circuit A⇔C to evacuate the inside of Q, and evaporate the solvent under
reduced pressure. If the need arises, it is advisable to check the pressure by a MacLeod
type vacuum gauge situated between the vacuum line and vacuum pump.
3. After evaporation has progressed to a desired extent, turn HG Plug M towards circuit
B⇔C and introduce N2 gas into Q.
*Note: Precautions are the same as 1. Notes 1-4 above.

19

13. Method of Transfer Liquid Between Schlenk Tubes
1. Liquid Transfer Methods through Tube Manipulation
In this method, turn the Tube‘s Cock of both the donating and receiving flasks towards
circuit A⇔C , and carry out the transfer procedures under N2 gas flow without the
intrusion of outside air.
The following is an explanation with reference to 20. Although not explicitly illustrated in
the figure, the N2 gas flows though the Bubl for each of Q1 and Q2.
1. U sing a syringe, transfer a liquid sample to Tube Q1, 20-1
2. Connect Q1 and Q2 with a 120º adapter (U-1056), 20-2
3. With the 120º adapter as the axis transfer a liquid sample from Q1 to Q2 while tilting
the entire connected apparatus to the left (this is the way it is displayed below). ⇒ 20-3
N2 gas

N2 gas

M1

B

A

C

A⇔C circuit

Q1

C
CC

20-2

A⇔C circuitS

U-1056120º adapter
C type

A
C

M2

Q2

M2

B

A

B

Inject by tilting
to the left

20-1

M1
A
C

C

B

Q1

Q2

20
2. Methods for Syringe Transfer of Liquid
When using a Syringe, steps to prevent the infiltration of air must be taken in advance.
There are two paths through which air can enter. One is intrusion through the gap between
the Barrel and the Plunger. The other is air infiltration through the tip of the long needle.
The traces of air that infiltrate through these pathways decompose the valuable sample(if not completely, at the very least to some extent). Color change can make it obvious that
decomposition has occurred at a particular part of the sample. To get N2 gas displacementfrom the inside of the Barrel and from the needle while keeping air out, place the tip ofthe needle into N2 gas and pull and push the Plunger several times to introduce andpurge the gas.
These procedures will be described with reference to 21-1 , 21-2 .and 33-A .
Note: It takes time to make a hole through a thick rubber stopper to insert the needle so an
adapter using a commercially available septum is presented.

20

N2 gas line (approximately 0.3-0.4atm)
V11
Thick rubber tube
Approximately
80mm length

Pinch cock
L

K
Black rubber tube
Approximately
100mm lengthD
H

U-1097
Septum

M1

I

21-1
21-2
holderCover witha fingerA

Syringe
cuit
C cir

R

A⇔

C

Needle tip
Plunger

B

BarrelQ1
Air passes throughthis gap

Black rubber tube

Syringe

J

J

TF tube21
Syringe

21-5
N2 gasflow“Pressure”
Method21-3
SeptumholderA typeU-1095A⇔C circuit
M2
A

M5
A⇔C circuit
A

C

21-4

B

N2 gas flow

Q5

M3 A⇔C circuit

C
B

A

U-1098
Septum holder

C
Q2

B

M4
A⇔C circuit

N4

A

C

“Pressure” Method

Q3

B

J
Q4

J
J

21

J

1. Push the Plunger to the bottom of the Barrel in advance. Then, pierce the needle
through septum holder connected to the black rubber tube J.
2. Open the N2 gas line valve V11, close rubber tube K connected to Bubl R with pinch
cock L. Then the N2 gas will flow through D→I→J and into the septum holder.
3. Cover the septum holder branch pipe with a finger. Doing this will lead the micropressurized (0.3-0.4atm) N2 gas flow to push back the Plunger, force its way into thespace or gap between the Barrel and Plunger, and remove residual air in this portion.
4. When the Plunger has been pushed back to the upper range of its scale markings,
remove the needle from the septum holder. Stand by after forcing back the Plunger tothe middle range of scale markings, then push the Plunger to the bottom of the Barrel
right before you draw up liquid in the next procedure. In this way, when the Syringe istransferred in the atmosphere, possible air infiltration can be extruded by pushing backthe Plunger even if air may infiltrate through the needle.

There are two liquid transfer methods of using Syringe – “suction” and “pressurization”.
a. “Suction” Method 21-4
1. T
 urn Cock M3 towards circuit A⇔C to release the flow of N2 gas and with the N2 gas
overflowing from the opening of Tube Q3 (stopper removed),
2. g
 et the needle to the bottom of Q3, draw up the liquid sample by suction,
3. a nd gently transfer by inserting the needle into a separate Tube. 21-4
b. “Pressurization” Method 21-3
1. Pierce the needle through septum holder N1 fitted to the opening of Tube Q2 , andturn M2 towards circuit A⇔C to supply the micro pressure of the N2 gas.
2. W hen the needle reaches the bottom of Q2, the surface of the liquid gets pushed down by
the 0.3-0.4atm N2 gas, and the liquid sample is transferred into the Barrel through theneedle.
3. Transfer the syringe to a separate Tube. Gently inject the liquid sample. ⇒ 21-2 , 21-3
4. When applying this method (for example when solvents and reagents that are being
saved or reserved are subdivided in a separate Tube Q5), fit a septum holder on
Schlenk bottle Q4 and insert a TF tube with inner diameter of 2mm into the mounted
septum. When the tip of the TF tube reaches the bottom of Q4 and the other end hasentered Q5, turn Cock M4 to circuit A⇔C . The liquid surface of Q4 will be pushed
down by the 0.3-0.4atm N2 gas and the solvent or reagent pushed out into Q5 throughthe TF tube. 21-5

22

14. Method of Transfer Solids Between Schlenk Tubes
The method for transferring solids from Tube Q1 to Q2 is described hereafter.
1. Tilt the two Tubes connected with a straight-type adaptor or 120º adaptor from rightto left (in the figure) to transfer the solids.

N2 gas

N2 gasB

A
M2

A⇔C circuitA⇔C circuit

A

M1

B

M1

C

A⇔C circuit

S

Q2
Q1

M1

U-1056120º adapter
C type

M2

A
C

B

A
B

C

Q1

Inject by tilting to the left

Q2

Q1
Q2

B
C

A

B
U-1053
Straight adapter
C typeA⇔C circuit
M1

C

A

A⇔C circuit
M1

M2

A
M1
C
B
Q2

A⇔C circuit

A

C

B
Q1

N2 gas23

2. Transfer Using Forked Wide-mouthed Adapter
Cover the opening of the forked wide-mouth adapter with a plastic film such as
Parafilm, and affix it with a rubber band around the adapter. Then, make a small hole byinserting a spatula to simply and precisely transfer a small amount of solid. 24
Do not overstretch the film. Stretch it with enough slack that allows the hole to work as anoutlet through which the N2 gas is overflowing.

23

Turn Cocks Q1 and Q2 to their respective circuits A⇔C to release only a small amount of
N2 gas. With this, the N2 gas will constantly overflow from the small hole that was createdwith spatula insertion, allowing prevention of outside air infiltration into the apparatus.
The following is an explanation with reference to 24. Although not explicitly illustrated in
the figure,the N2 gas flows though the Bubl for each of Q1 and Q2 as in 07.

Forked wide-mouth adapter
X
M2
RubberParafilm
band

C

A⇔

A

Z
Y
N

24-1

it
cu
cir

B

C

N2

Q2
N2

24

X

Parafilm

A⇔C circuit

N2

Rubber
band

M1

C

it
cu
cir

A⇔

A

A

Y

Z
B
C

C

B

24-2
Q1

Q2

N2

A

M1

B

N2
Hole

N2

Y

A⇔C circuit

SpatulaParafilm

C

Rubber band
M2
Z

24-3

A⇔C circuit
A

C

Q1

B

Q2
N2

24

1. Mount Tube Q2 ( receiver of thetransferred solid ), to Z and mountjointed-stopper to Y in advance.
⇒ 24-1
2. Allowing for some slack, cover theupper wide-mouth opening X witha plastic film, such as Parafilm,
and affix it with a rubber bandfrom the top.BC circuit
3. Next, turn HG Plug M2 towards
circuit A⇔C to introduce N2 gas
and then turn the HG Plug tocircuit B⇔C , Repeat the same
operation several times to achieve
pure N2 gas atmosphere in Q2.
4. W ith the N 2 gas overflowing,
remove the stopper that had been
fitted to Y, mount the donating
Tube Q1 (before mounting, turnM1 to circuit A⇔C , and leave theN2 gas overflowing). 24-2
5. Make a small opening by insertinga spatula from the center of thefilm and pry it open so that it
makes the shape of the N 2 gasoutlet. This will allow you to movethe spatula around freely.
6. Insert the spatula into donating
Tube Q1, pull up the scooped solid
sample up inside the adapter totransfer from Q1→Q2.
A ll operations are carried out
under an N 2 gas atmosphereinside the connected vessels.

15. Solid-liquid Separation Method
Filtration is basic in the separation of crystal from a suspended mixture (solid-liquid
separation), but this method is somewhat troublesome.
Use of the so-called “decantation method” circumvents troublesome operations whether
filtrate or solid is desired.
In this method, the mixture reacted in a Tube-type vessel is left to stand without
disturbance. The supernatant liquid is then taken away with care so as not to disturb the
precipitate.
This is an ideal method for recrystallization in which crystals that come out after heating
and cooling operations. Even when the crystal is a micro-powder, solid-liquid separation canbe done with ease, if the mother solution is separated gently.
There are “suction” and “pressurization” methods by using a syringe or Teflon (TF) tube.
1. “Suction” Method
1. When using a syringe, turn M1 to circuit A⇔C and leave the N2 gas overflowing fromthe opening of Q1. After placing a needle with inner diameter 2mm (henceforth referred
to as "needle") into the liquid in Q1, raising the "inner cylinder" will allow the liquidsample to be suctioned gradually into the Barrel. ⇒ 26-1
2. Put a ball filter on one end of a TF tube with a 3mm outer diameter and leave it in theliquid inside Q2. Penetrate the other end of the TF tube through the septum holder N3,
fitted to the opening of Q3, and after it has been inserted into Q3, turn M3 to circuitA⇔C , depressurize Q3 to allow gradual suction of the supernatant liquid. ⇒ 26-2
2. “Pressurization” Method
1. When using a syringe, pierce septum holder N4 fitted to the opening of Q4 with a needle.
Once the needle has reached the bottom of Q4, turn M4 to circuit A⇔C to Introduce N2gas. The surface of the liquid in Q4 will be pushed down by the 0.3-0.4atm N2 gas,leading the liquid sample through the needle into the Barrel. If there is no filter attachedto the tip of the needle, extract only the supernate, taking care not to disturb the
precipitate. Note that you should remove the needle from the septum holder once theliquid sample has been transferred; leaving it as it is can result in the Plunger flying off
due to the pressure of the gas. ⇒ 26-3
2. T
 urn M5 and M6 to circuit B⇔C in advance and leave the N2 gas overflowing from theopening of Q5 and Q6. Next, fit septum holder N5 to the opening of Q5 and insert a TF
tube ( outer diameter of ca. 3 mm ) through N5 Put a glass or other ball filter on one endof the TF tube and leave it in the liquid inside Q5 after inserting the other end into Q6.
The surface of the liquid in Q5 will be pushed down by the 0.3-0.4atm N2 gas, leading theliquid sample to Q6 through the ball filter. ⇒ 26-4

25

26

TF tube or plastic tube

Syringe
26-1

26-2
N3

N2 gas flow

Septumholder

M2

N2
gas
flow

M1
A⇔C

A

A⇔

it

circu

B⇔C circuit

A

A
C

irc

Cc

“Suction” Method

M3

uit

C

C

B

B

B

N2
Q2

Q3

Evacuation

N2
Q1

U-1161Glasscylindricalfilter

N5

U-1098
SeptumholderD typeSyringe

M5

TF tube or plastic tube

N2 gas flow

26-4
26-4
C

A⇔

“Pressure” Method

C

A⇔

A
C

B

B

N2
Q5

N4

Septumholder M4

it

Septum holder
U-1095
A typeA
C

U-1096
B type

B

N2
Q4

N2
Q6

0.3-0.4atm

ircu

Cc

A⇔

t
rcui

C ci

uit
circ

A

26-3

M6

U-1097
C type0.3-0.4atm*Note: The TF or plastic tube is not included in our products.

26

U-1098D typeU-1099E type16. Filtration in an N2 Gas Atmosphere
Filtration is conducted when, for example, the removal of micro-powder from a mixture witha micro-powder suspension (solid-liquid separation) is desired. The filtration using U-1012
and U-1015/1016-type Tubes connected through an adapter with reference to the below
diagram is explained hereafter.
Arrangement
1. P ut black rubber tube J1 on fromN2 gas line (approximately 0.3-0.4atm)
V11 via R1 to A1 of Q1.
2. P ut vacuum rubber tube from
V11
Thick rubber
tube
vacuum valve V21 to leg pipe C ofApproximately
D1
the selector.
80mm length
K1
H1
a
b
I1
3. A vacuum rubber tube is put
between side pipe A2 of M2 andL1side pipe a of the selector.
4. After the atmosphere in the wholeR1
system has been changed from air
C
J1
to N 2 gas, inject the suspension
Evacuation
onto the sintered glass filter X in
Q1( How to inject a suspension will
be explained separately.)
The following three methods are
M1
N
used for filtration, depending on
A1
the conditions.
*1 To transfer a suspension using a
C1
B1
Syringe, you have to use a ratherA⇔C circuit
Q1
X
thick needle. Depending on theabcase, cannulae technique usingZ
tubing made of metal, polyethylene,
Teflon , or glass can be easier.
Note, however, that cannulae for
medical use is not appropriate.
C

Ⅱ

Ⅰ

M2
A2
C2

B2
A⇔C circuit

Q2

27
V21
Bacuum line27

1. Gravity Filtration
In gravity filtration, you have to use another bubbler Bubl R2. Connect the black rubber
tubing from R2 to side pipe A2 of Q2. In this method, filtration of the suspension is carriedout with neither pressurization nor evacuation. The only thing you have to do is slowly
introduce N2 gas to Q1 through R1.You need not apply N2 gas from R2. A drawback of thisprocedure is that it takes a rather long time.
2. Pressure Filtration
The procedure is nearly the same as the gravity filtration.
Also in this procedure, you have to use another Bubl R2 and connect its black rubber
tubing to A2 of Q2. The only difference is to close K1 with a pinch cock; then the suspension
in Q1 is pressed out by the pre-adjusted pressure of the nitrogen line (0.3-0.4 atm) throughthe sintered glass filter X into Q2 to obtain a filtrate.
As the progress of the filtration, the pressure in Q2 is released through A2, R2 and H2.
3. Filtration under Reduced Pressure
In this procedure, the receiver Q2 is partially evacuated by a vacuum pump.
Depending on the extent of the evacuation and the vapor pressure of the solvent, thesintered glass filter can get stuck due to vaporization of the solvent.
Accordingly , pressure filtration is preferable.
1. P lace the suspension onto X.
2. Partially evacuate Q2 by manipulating the HG Plug of the selector and then close M2.
If you open the Cockplug Z, filtrate is collected in Q2.
Depending on the case, you may have to evacuate again.
If you do need to further evacuate, do not fail to place a cold trap between the selector
and the vacuum pump.

28

4. Filtration Method through Tube Manipulation● When filtrate is desired
1. Turn M1 to circuit A⇔C to allow N2 gas to go through Q1, remove stopper N while N2
gas is running through Q1. ⇒ 29-1
2. Using 120º adapter with a sintered glass filter, connect the donating Q1 and Q2 (N2gas displacement of Q2 already completed) 29-2 , turn M2 to circuit A⇔C , release thegas, and tilt the Q1⇔S⇔Q2 linked system from right to left to filter by gravity as
shown in 29-2 .

A

M1
M2

N

29

B

S

C

S

M1

Filter

Q1

A

A⇔C circuit

C

FilterB

Syringe

B C
A⇔C circuit

29-2
W

Septum

U-1097AA⇔C circuit
M2
M1
S

B

N2

Septum holder

M1tA⇔C circui

A

A

B

C
C
Q2

29-1

Q1

Q2

29-3

A

Q1

Evacuation

B
Q1

29-4

● When solid is desired
1. When a solid (crystal) is required, tilt the Q1⇔S⇔Q2 linked system to filtrate 29-2 .
While releasing N2 gas from septum holder branch pipe W on branch pipe A of M1,
pierce the needle of the Syringe through the septum and circuit A⇔C of M1. Place it sothat the tip of the needle reaches the inside of Q1 and inject the solvent and shake theapparatus to wash the solid. Then filter the mixture through the sintered glass filter 29-3 .
2. Remove S and Q2 from linked system Q1⇔S⇔Q2 and fix stopper N to Q1 to close it.
Turn M1 to circuit A⇔B . Remove the septum holder from branch pipe A.
After that, turn M1 to circuit A⇔C and apply vacuum through A, to desiccate the solid
to isolate it, as illustrated in 29-4 .

29

17. Distillation Apparatus for dry and N2 -Free Solvents

B

3way Stopcock
U-1037

Convenient distillation apparatus
for dry and N 2 gas free solvents is
illustrated herein.
The condenser is vacuum-jacketed toprevent from bedewing in summer or
wet season.
For details, see illustrations below.

N2 gasVacuumjacketC
Condenser(anti-bedewing)
U-3011：L=250mm
U-3012：L=300mm
U-3013：L=350mm

A
Bubbler type C Stopper
U-1003* For details, see page 53, 54.
Syringe

B
SeptumCylindrical Distilate Receiver
U-3021： 100mL
U-3022： 300mL
U-3023： 500mL
U-3024：1,000mL

C

Distilling Flask
U-3041： 100mL
U-3042： 300mL
U-3043： 500mL
U-3044：1,000mL
U-3045：2,000mLE

J

U-3002

H

SeptumD

Round Bottom Distilate Receiver
U-3031： 100mL
U-3032： 300mL
U-3033： 500mL
U-3034：1,000mL

I
#
A
B
C
D
E
F
G
H
I
J

Name of article
Bubbler type C
3way Stopcock
Vacuum jacketed Condenser(anti-bedewing)Distilate Receiver
Distilling Flask (2 necked)
3way Stopcock
120°bent Adapter
Schlenk Tube
Joint clamp
Support / Heater assembly

Bubblertype C
Stopper
U-1003Syringe

N2 gasSchlenk tube
U-1013：30mL
U-1014：50mL

HeaterA

Condenser(anti-bedewing)
U-3011：L=250mm
U-3012：L=300mm
U-3013：L=350mm

I Joint clamp
G Connecting
Adapter

3way
StopcockU-1037

N2 gasVacuumjacketD

F

3way
StopcockU-1037

Distilling Flask
U-3041： 100mL
U-3042： 300mL
U-3043： 500mL
U-3044：1,000mL
U-3045：2,000mL

F
3way
StopcockU-1037

E
J
Heater30

G

Connecting
Adapter
U-3002N2 gasH
Schlenk tube
U-1013：30mL
U-1014：50mL

18. Example Operations in Synthesis Reaction
With the synthesis of Pt(PEt3)4 as an example, we will explain operation procedures insynthesis reactions.
K2PtCl4 + 4PEt3 + 2KOH + C2H5OH ⎯⎯⎯→ Pt(PEt3)4 + 4KCl + CH3CHO + 2H2O
Reactant PEt3 and product Pt(PEt3)4 are both highly sensitive to oxygen. The former not
only gives off a strongly offensive odor, but is also a poison. Thus, it is necessary to use
it in an N2 gas atmosphere under a fume hood. For this, the N2 gas line fitted with
Bubl must be installed under a fume hood as well. The PEt3 will certainly be stored inan N2 gas atmosphere, but generally, the solvents, reagents, etc., used for the reaction,
recrystallization, extraction, and washing, must have oxygen removed through distillation
under a stream of N2 gas, vacuum distillation, degassing, etc.
Operation Procedure
1. S
 et up two 100 mL-Tubes Q1 and Q2 with a magnetic stirring bar as follows (illustrated
in 31).

N2 gas line (approximately 0.3-0.4atm)
V11

V12

D1
H1

Thick rubber tube
Approximately
80mm length

K1
L1

R1

D2
H2

K2
L2

M1
N1
C1

Black rubber tube
Approximately
100mm length
M2
N2
C2

A1

A2

R2

B1

B2

B⇔C circuit

B⇔C circuit

Q1

Q2
J1

J2
Stirring bar

Stirring bar
V21

V22

Vacuum line31
2. Place KOH (0.7 g, 12.5 mmol) to Q1, replace the air in it by N2 gas as explained in 10,
and connect black rubber tube J1 from R1 to the branch pipe A1. Open the valve V11,
then N2 gas flows out through J1, A1 and B1. Turn M1 to circuit A⇔C and remove thestopper N1. N2 gas through J1 is now flowing out from the opening of Q1, through which
you can introduce water (1 mL; degassed and stored in a separate Tube under N2 gas)31and EtOH (30 mL; degassed and stored in another separate Tube under N2 gas) bymeans of Syringes. Stir the mixture until a homogeneous solution is obtained and thenadd PEt3 (3.0 mL, 20mmol;stored in a separate Tube under nitrogen). Put the stopper N1back to the opening this operation makes N2 gas flow out through R1 and H1; you may
leave the N2 gas flowing out
3. To the other 100 mL-Tube Q2, place K2PtCl4 (1.5 g, 3.6 mmol; this is air stable and noneed to store under N2 gas) and replace the air in Q2 as explained in 10, and connect
black rubber tube J2 from R2 to the branch pipe A2. Open the valve V12, then N2 gas
flows out through J2, A2 and B2. Turn M2 to circuit A⇔C and remove the stopper N2.
N2 gas is now flowing out through J2 and the opening of Q2, through which degassed
water (10 mL) is added to dissolve K2PtCl4. Withdraw the resulting solution by means ofa Syringe, put the stopper N2 back to the opening and close V12
4. N ow you add the solution taken in the Syringe obtained in the previous operation to thesolution in Q1 as follows. Open the stopper N1; N2 gas is now flowing out through J1 andthe opening of Q1. Insert the needle of the Syringe and add the solution in the Syringe
to the solution in Q1 slowly (over some five min). During this operation, N2 gas is flowing
out from the opening. There is no need to flow rapidly, but if the flow rate is too low, air
may come in through the opening. You can check the flow rate by inspecting the bubbling
through R1 simply by covering the opening with your finger; if the rate is too rapid or
slow, control by manipulating V11.
5. A fter the solution has been added after some five min, close N1 and stir at room
temperature for 1 h, then at 60 oC for 3 h. Then, cool the solution to room temperatureand the resulting mixture is concentrated as follows. Connect the vacuum rubber tube
(fitted to V21) to pipe A1 and turn M1 of Q1 slowly to circuit A⇔C to evaporate thesolvent and volatiles under reduced pressure. An orange oil containing a solid is obtained
after the evaporation.
6. Turn M1 of Q1 to circuit A⇔B and connect A1 to the black rubber tube J1 to flow N2
gas through J1, A1 and B1, then turn M1 to circuit A⇔C to introduce N2 gas into Q1.
Take away the stopper N1 to allow N2 gas to overflow from the opening of Q1. Add
degassed hexane (15 mL) from the opening by means of a Syringe and stir the mixture
thoroughly to extract the product.
7. The extract taken out by a Syringe is a suspension, which can be filtered as described in
27(Note that the whole glassware must be assembled under N2 gas).
8. Thus, the suspension is placed onto the sintered glass filter fitted to a Tube at the top of
the setup to allow the extract is filtered into the bottom Tube. Repeat the extraction andfiltration using the same apparatus to collect the second filtrate also in the same Tube.
9. Remove the top part of the assembly (i.e. Tube fitted with a sintered glass filter) andevaporate the combined filtrate under vacuum as described in 5. until the volume is
reduced to 7~8 mL and N2 gas is introduced by manipulating M. Open the stopper N toallow N2 gas to overflow, add PEt3 (0.5 mL, 3.4 mmol) to the residue, close N and cool theTube to -78°C to precipitate colorless solid product.
10.Remove the supernatant liquid using a Syringe as illustrated in 26-1 . Wash the solidwith 3mL of degassed hexane that has been cooled to -78ºC. Remove the washing using a
Syringe. Repeat the same washing procedure, connect the pipe A to a vacuum pump andapply vacuum at -40 ºC to dry the solid. By manipulating M, introduce N 2 gas. In
general, 2.0-2.2 g of the product can be obtained in this way.

32

19. Introducing a Sample into the NMR Tube
1. Pierce NMR tube S through the hole in the lower screw cap of “NMR tube holder”(U-2001) and tighten securely. In this way, the rubber seal fitted inside the screw cap willhermetically seal and tightly fix S., thus, the whole apparatus assembled is turned into a“Schlenk tube with an NMR tube”.
2. Next, turn the Cock to carry out the operation shown in 10 to replace the air with N2 gas.
3. Remove the stopper from the socket on top. Turn M to circuitA⇔C and leave the N2

gas overflowing from the opening top of Q , using a Syringe, inject the sample into S as
illustrated in 33-A.
4. When the plastic stopper to shut S is male, pick it up with tweezers and put it to the
opening of S to close it tightly. Loosen and uncap the lower screw cap of the “NMR
tube holder” and pull S out. Just in case, stretch and wrap Parafilm over the point ofconnection between the stopper and S opening, to ensure hermeticity, and measure NMR.
5. When the plastic stopper to shut S is female, displace the air with the stopper inserted
into the interior of the “NMR tube holder” in advance. After removing the air inside thestopper as well, pick it up with tweezers to place it over the opening of S. Close tightly
and follow the same procedure as in 4.
6. H
 ermeticity of the connecting point between the opening of S and the stopper after the“NMR tube holder” has been removed is not maintained perfect, so be careful whenmeasurements take a long time to carry out.
U-2001
NMR tube holder
A typeSyringe

33-A
N2
gas
flow

StopperA⇔C circuit

Stopper

M
CAS

U-2002
NMR tube holder
B type

B
S

Q

33-B

N2 gas7. In view of the comment in 6., it is necessary to take more secure procedure, for instance,
when the time course of the reaction is followed and the temperature is changed during
the reaction.
In such cases, custom-made NMR tube holder with a leg made of the same material,
thickness, and diameter as S (“NMR tube holder” should be used. After connecting S

33

to this leg by glassblowing technique and introducing the sample according to the tips
described in 2. and 3., melt and seal off S from the leg by gas flame. Note that S must
be symmetrical in all directions; you need some technique of glassblowing. The tube S
obtained in this way is completely airtight.
20. Melting Point Measurements in Inert Gases
When you are preparing organometalic complexes, you may have to measure their melting
points of air sensitive complexes. The technique is somewhat similar to that of transfer ofsolid materials shown in 24, which you should keep in mind.
You should select an appropriate folked adapter, Q1 where a sample is stored under N2 andempty Tube Q2.
1. The sample in Q1 must be crushed

U-1163
Pestle rod

into fine powder in advance bymeans of a glass pestle.

N2
M1

A

2. An empty capillary tube T, one end

Xof which is sealed, is placed into Q2

M2
A

B

with the open end facing down.

Z

YC

Then, replace air with N 2 gas inC

Q2 containing T by manipulating

B

Cock M2.

34-3
Q1

Q2

3. Q1 and Q2 thus prepared are
Tweezers

set to the legs of an appropriate

Capillary tube

forked adapter, while N 2 gas

34-1
T

N2

N2

is overflowing from the forked

N2

X
Parafilm

adapter through its top opening.
Rubberband

M2
U-1093Forkedadapter

M1

The opening is then covered with aplastic film (Parafilm) and make asmall hole to insert tweezers.

Z
B⇔C circuit

B⇔C circuit

4. While N2 gas is overflowing fromthe forked adapter through thesmall hole, pick T up with tweezers

Yand transport it to Q1. The open
end of T is pushed to the powder
34-4

T

34-2
Q1

sample at the bottom several
times to stuff the sample into thecapillary.

Q2

These consecutive operations areT

34

illustrated in 34-2 , 34-3 , and 34-4 .
Read the following procedures whilereferring to 35.

34Capillary tube

35-2

T

N2

N2

X

Parafilm

U-1093Forked adapter

Rubberband

ZYB⇔C circuit

B⇔C circuit
T

T

35-1

35-3

N2

no risk to be exposed to externalair.
6. F i n a l l y, Q 2 i s t u r n e d t o ahorizontal position, pull
capillary T out a little more withtweezers and seal quickly with agas flame at the middle partabout 20mm down from the open

X

Forked adapter
N2

N2

Y
Z
Q1

35-4

C
Q2

Q2

end. ⇒ 35-6

N2

35-5

All the operations have now been
completed.

N2
N2

illustrated in 35-1 , 35-2 , and35-3 .
6. Remove Q1 and Q2 from theforked adapter. Q1 is not needed
anymore; put a stopper on it andstore safely.
5. Q2 is then turned upside down
and shake or vibrate thecapillary to get the sample to go
towards the bottom of T. ⇒ 35-5
During the operation, the open
end of T is located in the streamof N2 gas through Q2. There is

Q2

Q1

5. The following is just the opposite
to 4. The capillary tube T isreturned back to Q2 by means oftweezers.
These consecutive operations are

N2

T

A

35-6

N2

B

U-1031B⇔C circuit
Q2

C

T

U-1034

N2

35B

35

Illustrated for 21 on the next page.

35

21. Thin Blade Adapter
Apart from liquids, using standard adapters for transfer of solid samples between Tubes
can cause the solid to jam at the thick joint tip, preventing smooth transfer.
For example, as in 30, when the reaction is carried out in Q1, with a Socket opening, some
sort of adapter is required to transfer the solid sample obtained to another vessel. If a
standard straight-type adaptor (U-1053) is used in this situation, the thickness of the joint
portion acts as a barrier. The valuable solid and crystal gets jammed and cannot betransfered smoothly. In such cases, it is convenient to use a custom-made thin blade adapter(Custom order), with the tip of its joint portion as thin as a blade, such as the one shownin 36. It is necessary to carefully remove the grease from the opening of Q1 with a tissue
prior to attaching this adapter. The blade can be nicked easily, so while it is not in use, cover
it with a stopper to protect it.

Ⅰ

Ⅱ

Causing thesolid to jamat the joint tip

The solid canbe smoothly
dropped down

Q1

Thin Blade Adapter
U-1253Customorder

U-1053Customorder

U-1062Cap ♀・15/20

U-1064Cap ♀・29/32

Q2

36

22. To Transform the Flask Into a Schlenk Tube-Type Reaction Vessel
In some cases, one may want to have another Cock during a procedure, or to use a large
3-necked flask as a Tube-type 3-necked flask during the experiment. The above illustrated
adapter with a Cock (U-1031,U-1034) will come in handy in such cases. This adapter isvery convenient as it allows you to add another Cock without reducing the number of flask
openings.
*Due to editing reasons, the cock (U-1031,U-1034) is illustrated in the former page. 35-B

36

23. Solvent Container to avoid frequent distillation
Many research labs use distillation apparatuses to dry or distill common solvents under N2gas. However, there are approximately 10-20 common solvents, including those used only
occasionally, thus it doesn’t make sense to reflux and distill every time. Also, for operations
like recrystallization, one may encounter a sudden need for a solvent not frequently used.
Apart from the case in which only a small quantity, readily available by simple degassing, isneeded, doing reflux and distillation at that time would cause a large loss of time. By having
many different kinds of solvents and water saved and reserved in Schlenk bottles 37 for use
at a time like this, you can avoid the troublesome procedures for degassing and drying ofsolvents and reagents described in 09. This allows experiments to proceed simply, reliably,
and rapidly.
The solvents stored in Schlenk bottles can be used without a time limit if you operate
carefully as you treat the Tube. When you close the stopper after taking the needed amountof solvent, thoroughly carry out the procedures required not to allow air to infiltrate into
the bottle as explained in 07

Schlenk bottle
A typeSchlenk bottle
B typeU-1020:100ml
U-1021:
250ml
U-1022:500ml
U-1023: 1,000ml
U-1024: 2,000ml

Solid tube

U-1025:100ml
U-1026:250ml
U-1027:500ml
U-1028: 1,000ml
U-1029: 2,000ml

U-1042
5ml

37

Trust in the group is indispensable for shared use of solvents stored in Schlenk bottles.
Absolutely avoid sharing with individuals who tend to skip over the operating tips or thosewith a weak sense of responsibility. Schlenk bottles U-1020~1024 have Socket opening
with a slightly shorter Socket on the cap. In this design, care has been taken to strictly
prevent the grease from coming into the bottle. ⇒06
Some bottles like U-1120~1124 have greaseless valves. Because the Schlenk bottle is a large
flat-bottomed glass vessel, take into account the possibility of rupturing when evacuated.
Just in case, it is recommended to evacuate after putting the bottle into a cloth bag with astring tying the opening.

3724. Storage Vessels for Solids
Solid tube (U-1042) illustrated in 37 is a storage vessel for samples that decompose byoxygen or moisture. This vessel has a simple structure that allows switching the flow of N2
gas simply by turning the Cockplug that also serves as a stopper.
If the sample sticks to the female joint when transferring from this vessel into another bymeans of spatula, wipe the joint with a paper-tissue. Thoroughly carry out the evacuationnitrogen introduction procedures and ensure the complete displacement with N2 gas inside
the solid tube. When storing the sample, turn the stopper from the position shown in 37
180º to shut it tightly and isolate the interior from outside air.
If you make large crystals of compounds
like Pd(PPh3)4, the vessel can be used tostore them for a number of years. However,this vessel is unsuitable for compounds that
require strict exclusion of air or moisture,and use Tube like U-1015 with Cock.
25. Separating Funnel
The separating funnel shown in 38 is onlyused for large-volume extraction or washing.
For small-volume extraction and washing,
add extraction solvent or water to the Tubeor Schlenk flask that contains a sample
solution. Consecutively shake or stir andthen leave it to stand. It is much easier toremove upper or lower layer with a syringe
after that. Also, this ensures the strictness.

Schlenk separating funnel
U-2121:
500ml
U-2122: 1,000ml

38

26. Handling Silica Gel etc. Used as a Desiccant and in Column Chromatography
In extraction and washing described one of the in aqueous in most cases. If you need toget an organic layer, you must desiccate with a drying agent, which contains oxygen. The
silica gel and alumina for the column chromatography also contain oxygen. So adding themas such would lead to oxygen contamination. Thus, prior to use, you must insert the silica
gel and alumna into a Tube-type vessel, heat at a temperature of about 100-150ºC, andevacuate for several hours to deoxygenate them (do not forget to set up a cold trap). You
must only use the silica gel or aluminum after carrying out these procedures, cooling toroom temperature and introducing N2 gas. Because moisture is also removed during theprocedure, the silica and alumina for the column chromatography become highly active (theadsorptive power increases); you must add an appropriate amount of water to reduce theiractivity after the procedure.

( 2018 Spring )38

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