1 sales unit = 1 pack of 50 PTFE sealing rings on an adapter tube
(polypropylene) fitting the diameter of the glass joint.
News
Good news: We have our product permanently in stock for delivery to our
distributors. In case your local distributor says that the product is
currently not available, you may buy from another distributor listed in our
table below.
Please contact Dr. Glindemann at
dglinde@aol.com if
you currently experience ordering problems with your distributor.
Worldwide customers:
"GLINDEMANN
PTFE Sealing Rings" are sold by Sigma-Aldrich
(Millipore Sigma).
Search Sigma-Aldrich web-shop for
"glindemann" or enter Sigma-Aldrich catalogue number from the
table below. You may also search Google for a Sigma-Alrich catalogue number,
such as Z502081, and will find a variety distributors who sell the product.
USA customers:
www.labunlimited.co.uk does export worldwide including the USA (most other European
based distributors do not export to the USA). If you are based in the USA and
can not open an account with Sigma-Aldrich (Millipore Sigma) you can order from
www.labunlimited.co.uk.
Prices of
GLINDEMANN
PTFE Sealing Rings
Our recommended list prices for end-users for the most common sizes (for
joint 14 to joint 29) are around 30 € per sales unit (1 sales unit = 1
pack of 50 PTFE rings).
In practice, end-user prices for the most common sizes (for joint 14 to
joint 29) range from 20 € to
60 € per sales unit (1 sales unit = 1 pack of 50 PTFE rings) dependent on distributor and
order quantity. Most distributors offer discounts on bulk quantity orders.
Joint diameter- Do not be confused by joint names
such as "14,5" instead of "14", "18,8" instead of "19", or
"29,2" instead of "29". Glindemann sealing rings fit these joints.
Joint length
- Do not be confused by joint names such as joint 29/32 which means for this
joint 29 the length is 32 mm. Glindemann sealing rings fit joints of all lengths, preferably medium-length
joint and
long-length joint. With short-length joint you may have to
inflate the diameter of a sealing ring by
stretching with little force.
Glindemann
Catalogue No.
K7
K10
K12
K14
K19
K24
K29
K34
K45
K70
Distribution in
Number of Sealing rings / unit
(pck)
50
50
50
50
50
50
50
50
50
50
Distribution worldwide (200 countries) by
SIGMA-ALDRICH (named Millipore Sigma
in USA/Canada).
Search the Sigma-Aldrich shop for "glindemann" or enter Sigma-Aldrich catalogue number below.
Buy with the Sigma-Aldrich product number from your local distributor:
In
North-America (USA,
Canada, Mexico), you can also order from Fisher Scientific, Thomas
Scientific, Krackeler
Scientific, etc., using the Aldrich-catalogue numbers. Please contact Dr. Glindemann
at dglinde@aol.com if
you currently experience ordering problems.
Other worldwide or regional distributors.
USA customers:
If you wish an alternative to Sigma-Aldrich you can order from
www.labunlimited.com
(search for 'glindemann' or click Home > Laboratory > Distillation,
Separation, Filtration > Distillation, Synthesis > NS Joint Accessories >
PTFE sealing rings for jointed glassware. Most other European based distributors do not
export specifically to the USA.
Lab Logistics Group (LLG).
LLG is the central organisation of a cooperative of about 30 privately owned
laboratory dealers in Europe, Asia and Australia.
In case you do not find the product in the web-shop of your dealer, contact
them with the LLG catalogue number and they will order the product from LLG
for you. This network of national
partners distributes in many countries.
Foto:
For sale is 1 pack of 50 PTFE sealing rings on an adapter tube (polypropylene)
fitting the diameter of glass joint 29 mm, Glindemann-product-no. K29.
Instruction where to use and how to use
GLINDEMANN®-sealing rings Application: Laboratory
work with glass equipment and chemical storage containers often demands hermetic and clean sealing of
conical joints and stoppers. Joint grease is often not optimal (dissolution,
contamination, leaking). The
known PTFE-joint sleeves and stoppers are expensive and not very tight. Therefore, a fine
PTFE-ring seal made off PTFE
(known as Teflon) on ground tapered glass joints has been developed.
Use for hermetic sealing of equipment and containers without grease. Pressure- and
high-vacuum tight (gas leak rate below 10-6 mBar l /sec). Chemically resistant and tight
(solvent leak rate below 0.2 mg/day). Temperature resistant (-200 to +300oC). No
irreversible jamming of the joint. Useable with all joint clamps. Reusable. Available for
all joint calibres: NS 7, 10, 12, 14, 19, 24, 29, 34, 45, 50, 60, 70.
Procedure:
Slip a sealing ring onto the male part of the joint.
The ring adheres by elastic tension. One ring is normally enough. Two rings with
about 3 mm distance. Make sure that the ring is not twisted.
For sale: 50 sealing rings on a tube,
fitting the diameter of
the male joint part. Be aware that for the application on rarely used short-length joints the
adapter opening can be increased in diameter to fit the joint.
The sealing ring looks on good joints "tightly"
transparent like grease.
Gently press the glass parts together.
The
ring must look transparently "tight" all around. Do not break the joint by
overstressing. For less smooth glass joints a miniscale amount of grease,
solvent or water should be added to the ring as softener.
The glass parts of the joint can also be rotated and rubbed to produce microscopic PTFE-filings
which smooth the glass.
The sealing ring becoming "visibly" tight On the left: Ring before pressing the 2 joint parts together
Centre: Ring after pressing - transparently like grease.
Under pressure the PTFE, although free of grease, flows like grease into the uneven
surface of the ground joint
On the right: Compared to a greased joint, equally transparent.
But grease is not solvent resistant and not very clean.
Disconnect the joint by moving one part of the joint back and forth (do not pull). With 2 rings extra motion
back and forth.
QUESTION: Ordering. Where can I order these PTFE sealing
rings? ANSWER: Search the list of distributors at this homepage. If your home
distributor is not on the list ask it to manage to buy sealing rings from one of the listed
distributors for you.
QUESTION: Sizes. Are sealing rings available for all joint
sizes? ANSWER: Yes. Rings are available for 7...70 mm taper diameter.
QUESTION: How does the PTFE ring seal work?
ANSWER: The plastic PTFE (known as Teflon) of the sealing ring acts similar to joint
grease. But PTFE is much more clean and chemicly inert than joint grease. The PTFE flows
under high pressure slowly like grease or wax into the uneven spots of the ground
glass surface. By this cold flow the free leakage volume between the 2 joint parts is
filled and sealed by PTFE. PTFE is in fact much harder than grease or wax. To make PTFE
flowing like grease it must be under a very high pressure. This pressure is produced by
pressing the 2 glass joint parts together. But the force to produce this pressure is
applied to the PTFE and the glass as well. This force can break the female part of the
glass joint by tensile stress. But the glass is of course not allowed to break ever.
Therefore, the PTFE ring is shaped to contact the surface of the ground joint only at a
very small area (just the area of the 0,6 mm wide ring). If you force the 2 glass joint
part together they contact each other only via the small PTFE ring. This relatively small
force results therefore in a comparatively large deformation pressure on the PTFE. With
this theory on PTFE ring seals in mind you can use the following rules to use these rings
more efficient: Any factor which makes the PTFE more soft makes the seal better (high
temperature, presence of traces of plasticizers, solvents, water, grease). Any factor
which makes the ground glass surface more smooth makes the seal better (polishing of the
glass surface). Any factors which gives the PTFE more time to flow makes the seal better
(usually the final sealing is better a few hours after pressing the joint together).
QUESTION: Joint Clips.
Can I use these PTFE sealing rings with common joint clips? I tried
Keck®-type clips with joint sleeves (PTFE) with sealing ribs and the clip
did not fit.
ANSWER: Glindemann rings are very thin (0,07...0,1 mm) and can therefore
normally be combined with all types of joint clips (clamps), including Keck-type
clips made of plastic or nickel metal or PTFE-coated metal. In
addition, all types of adaptable joint clips with springs and screws can be
used.
Foto: Glindemann ring combined with Keck® joint clip
Foto:
Glindemann ring combined with Clipox® joint clip
QUESTION: I have doubts that a PTFE ring can seal a glass joint properly. I
used PTFE-sleeves and found they have no sealing properties compared to a bare glass
joint.
ANSWER: The common PTFE sleeves which do not have sealing ribs have in fact no sealing
effect because they do not work like PTFE rings. PTFE sleeves that contact the whole joint
do not allow a sealing pressure high enough to make the PTFE flowing like grease.
PTFE sleeves seal much better if they have sealing ribs (groove, profile)
but the are still not useful for a long static vacuum.
QUESTION: Sealing Containers. Can I use the PTFE sealing
rings to seal containers with glass taper stoppers? (Reagent tubes, flasks, erlenmeyer
flasks, bottles)
ANSWER: Definitely, this works great. You fill find, that the PTFE sealing ring will make
the glass stopper fixed in the container. Therefore, a slight overpressure in the bottle
will not push out the glass stopper. To loosen the glass stopper, do not pull the
joint parts apart because this needs too much strength. Instead, move the stopper to and
from several times or rotate one joint part.
QUESTION: I can not remove the stopper with a sealing ring from the joint or bottle. Why
are the glass joint parts with a sealing ring stuck if I try to pull them apart?
ANSWER: Do not pull the joint parts apart because this needs too much strength.
Instead, move the stopper to and from several times or rotate one joint part.
QUESTION: Can I use the ring more than one time?
ANSWER: Yes. The ring can be removed from one joint and can be transfered to another
joint. But scratches and dirt can make it less tight over the time.
QUESTION: How can I remove the PTFE sealing ring from the glass joint?
ANSWER: Just slip it off. The PTFE rings adheres to the male glass joint just by elastic
tension, which prevents the PTFE ring from falling of the male glass joint.
QUESTION: Extra tight seal. I used a PTFE ring seal and found
the sealing not proper enough.
ANSWER:
Inspect the seal if it looks transparently "tight" all around the joint. If
there are "bad" looking spots (one millimeter is enough to cause leakage) then
the ring is probably scratched or dented.
Some times the surface of the ground joint is simply to rough to fit the PTFE ring seal. There are different possibilities to smooth out the roughness of ground jointed glass
ware. The joint with a PTFE ring seal can be rotated and rubbed to produce
microscopic PTFE-particles which smooth the glass at the PTFE-contact zone forever. This
zone of the joint looks like greased but it is in fact a layer of small PTFE particles
which fill out the uneveness of the ground glass. To make the smooth contact zone broader
move the PTFE ring on the joint and rotate the joint parts again. Remove larger visible
PTFE-fibres after this procedure. The PTFE-ring used for rubbing has to be sacrificed
often because it looses larger PTFE-particles which make the ring uneven.
Foto:
Extra tight seal.
Smooth a 2 mm zone of the male glass joint with PTFE filings from a ring by rubbing.
Sacrifice this ring used for rubbing. Slip a new PTFE Ring onto the smoothed zone. This
extra smoothing will result in an almost hermetic extra tight seal.
But you can of course use PTFE sealing rings without this procedure, for most purposes.
Another possibility is to soften the PTFE sealing ring. This can be performed by
applying a micro scale amount of grease or solvent or water.Do not clean
your jointed glass in Potassium Hydroxide solution which makes ground glass even more
rough. You can also ask your glass blower for slightly polishing the joints. A simple home
made fire polishing procedure is to direct a very hot welding flame (more than 2000oC)
for a few seconds (do not deform the joint) directly around the grounded glass surface. back to the top
QUESTION: Extra clean work: How can I extra clean the PTFE ring for ultra clean
work (biochemical, pharmaceutical, analytical, organometal work) ?
ANSWER: You can either bake the ring or you can extract contamination with solvents.
Baking: The PTFE ring can be baked at 300 oC in an oven. But do NOT put the plastic
storage tube at heat over 100 oC! Slip the PTFE ring on a male glass taper
stopper to prevent it from shrinking .
Solvent extraction: You can bathe, purge or rinse the PTFE rings with any useful solvent
(PTFE takes any organic solvent). You can also put many PTFE sealing rings alltogether in
a Soxhlet Extractor and rinse them with the solvent, which has a boiling temperature below
70 oC (at higher temperature, the rings will start to shrink).
Take care, that this cleaning (baking or solvent rinsing) will make the PTFE less soft and
reduce the sealing power slightly. If you want to soften the PTFE ring again, you can add
a micro amount of any greasy, oily or slippery chemical which does not harm your
laboratory work.
QUESTION: How can I prevent that the sealing ring teared up and fell off the joint
after baking/heating over 200 oC?
ANSWER: Slip the ring before heating on the thinner part of the taper joint.
QUESTION: I took the ring off the joint and it contracted to be too
small to install it again on a taper joint.
ANSWER: You can inflate the ring to fit again the joint. Inflate the ring with
the plastic adapter which you bought together with the rings from your trader. You can also use
two fingers, sticks, nails etc. Foto:
Sealing ring contracts (shrinks)
if removed from the joint.
QUESTION: The sealing ring became to large in diameter and fell off the
joint.
ANSWER: The diameter of the ring can be decreased by use of high temperature of 100...300
oC (oven, lighter, Bunsen burner).
back to the top
Chemists' user opinions, test reports
and literature about GLINDEMANN rings
1. Test report
of GLINDEMANN-PTFE-sealing rings for ground tapered joints
from: Dr. Andreas Bolte, Group Prof. Dr. Borislav Bogdanivic,
Max-Planck-Institute of Coal-Research, Germany Dear Dr. Glindemann:
Our inorganic and organometallic laboratory research needs often absolute clean and tight
sealing of tapered joints on glass equipment.
Your PTFE-sealing rings proved to be a success while:
long term sealing of high vacuum equipment,
long term sealing of inert equipment until 200oC,
sealing of equipment and containers for synthesis and storage of dangerous (inflammable in
air), oxygen sensitive and moisture sensitive chemicals,
sealing of equipment where contamination of reaction mixtures by joint grease has to be
avoided.
Our group has gone over to use Glindemann-sealing rings instead of joint grease or
PTFE-sleeves because of the amazing sealing properties and the advantages of working with
greaseless joints.
(some extended information in the German version is not translated here)
We consider your PTFE-sealing rings as the present most advantageous way to work with
greaseless and tight joints.
(signed by Andreas Bolte, 1997)
2. Test report of
GLINDEMANN-PTFE-sealing rings for ground tapered joints
from: Professor Michael D. Fryzuk, Department of Chemistry, University
of British Columbia, Canada Dear Dr. Glindemann:
Thank you for the sample of your amazing o-ring seals. We have used Teflon sleeves in the
past for certain situations but we have discontinued this practice because they are too
expensive and not particularly effective. We have tested your o-ring seals using an
extremely air-sensitive solution of {Co2TiCl}2ZnCl2 in
toluene. This material is our indicator for O2 in our inert-atmosphere glove
boxes since it goes from deep blue green to bright orange in the presence of 5 ppm of O2.
A tube with 3 mL of this deep blue green solution was sealed with a stopper that had one
of your seals and no grease inside an inert atmospheres glove box; the tube was then
removed to the outside and inverted so that the solution was on top of the stopper. The
colour could be seen to penetrate to the o-ring seal and no further. And amazingly, the
solution remained blue green for many days. This tells me convincingly that this seal is
airtight and robust. I would buy such a product because it is ideal for our research on
air- and moisture-sensitive organometallic complex compounds.
Sincerely,
M. D. Fryzuk
for <dglinde@chem.ubc.ca>; Tue, 10 Mar 1998 08:47:40 -0800
3. Test report of
GLINDEMANN-PTFE-sealing rings. from: Fan Ouyang, Beijing
University of Aeronautics and Astronautics, April 24, 2003 My name is Fan Ouyang. I am a senior undergraduate at Beijing University of
Aeronautics and Astronautics. I am now engaging in a new compound synthesis.
In our synthetic chain, there was a key link that should be reacted at high
temperature (>110℃)
and high pressure (>8 Bar) for 12 hours. To realize the condition, we designed
thick-wall glass tube to bear the high pressure, but in practice, we found the
standard conical joints could not meet our hermetic requirement that a
low-boiling-point reagent (5 ml) leaked completely in less than one hour.
Fortunately, in a journal, we saw the Glindemann-Sealing Ring. These sealing
rings were designed for standarded conical joints that they are available for
all joint calibers: NS 7,10,12,14,19,24,29,34,45,50,60,70.
We used the 19-sized sealing-ring. As it was described at the references, the
sealing ring was very effective. Not only could it be used under high
temperature, but also after 12 hours reaction with the high air pressure, the
low-boiling-point reagent leakage rate was less than 10% (0.5ml/5ml).
Thanks to the Glindemann sealing-ring, our experiment finally got a complete
success.
So I am glad to introduce this effective and convenient ring to my dear
colleagues in China. Besides their excellent hermetic and vast application
conditions, they can conveniently change a common joint into a hermetic joint
so that it can save the investment on specialized equipment.
我叫欧阳凡，现在是北京航空航天大学大四学生。我现在正在合成一种新型化合物。在我们的合成路线中，有一个非常关键的步骤，需要在高温（>110℃）高压（>8个大气压）条件下反应12小时。
为达到这一目的，我们设计了厚壁的玻璃仪器来承受高压，
但是在实际操作中，我们发现标准磨口在我们的实验条件下不能达到要求的密封程度，一种低沸点的反应物（5ml）会在不到一小时完全泄漏。很幸运，在一本杂志上，我们发现了Glindemann密封环的广告。这种密封环是专门为标准磨口设计，型号有7、10、12、14、19、24、29、34、45、50、60、70，可以应用于各种磨口。抱着试一试的心态，我们使用了19口的密封环。正如其产品说明中介绍的一样，这种密封环非常有效。其不但可以在高温下使用，而且在>
8个大气压的气压下反应十二小时后，低沸点的反应物泄漏不超过10%（0.5ml/5ml）。在这种密封环的帮助下，我们的实验最终取得了成功。因此我很乐意向大家推荐这种密封环。
除了其优异的密封性能和广泛的使用条件，其最大的优点就是可以方便的使普通标准磨口达到很好的密封性，可以节约专门的密封设备的投资。这尤其适合中国的国情。
4.
Test report of
GLINDEMANN-PTFE-sealing rings. from: Dr. Konstantin Chernichenko,
University of Helsinki, Department of Chemistry, August 3, 2016 Dear Dr. GLINDEMANN,
...I would like to express my gratitude to you for invention and
commercialization of the rings. I hardly imagine my lab work without
Glindemann rings, I use them not only for gas-tight reaction like
hydrogenations, but for all the synthetic work I do and encourage students
and colleagues to do same. In fact, I haven't been using any grease since I
found out about the rings from a colleague some 7 years ago.
5. Opinion on
GLINDEMANN-PTFE-sealing rings in the blogosphere.
from: an unknown user "mrj" at
http://blogs.sciencemag.org/pipeline/archives/2008/05/30/ah_glassware
"...21. mrj on May 31, 2008 10:53 PM writes... ... Glindemann sealing rings (www.glindemann.net)
... are just so
superior to grease or teflon sleeves, there is no comparison. I don't use
anything else for high vacuum work ... ."
6.
Opinion on
GLINDEMANN-PTFE-sealing rings by glassblower and author Gary S. Coyne.
Gary has been impressed by the ring as soon as he saw it back at the 2001 ASGS
(American Scientific Glassblowers Society) symposium at Colorado Springs where we had a chance
to meet personally after my oral lecture and presentation of my rings.
See
Glassblower
Gary Coyne's joint-grease advices (download here), the now expired
source link of which I made this copy was
http://www.sas.org/E-Bulletin/2002-09-20/labNotesCoyne/body.html. This note
compares fluorinated greases such as Krytox®), Silicon greases and
Hydrocarbon greases (such as Apiazon®). The author states
"An alternative to stopcock greases is Teflon stopcocks, Teflon rotary
valves (for high vacuum) and Teflon sleeves. If you need high vacuum and
cannot use a standard Teflon sleeve, you may want to check out Teflon
rings http://www.glindemann.net/.
"
See also Gary's helpful book, written with the skills of a glassblower and with
writing skills like a professor:
Gary S. Coyne. The Laboratory Companion: A Practical Guide to Materials,
Equipment, and Technique. Wiley-Interscience; Revised (18. November
2005) ISBN-10: 0471780863 ISBN-13: 978-0471780861. This book contains a chapter on the problems of jamming,
leaking and sealing of glass joints of laboratory glassware. The book also
compares all types of joint greases, and the tradeoff between typical
problems of joint grease (high-vacuum, but only to the point ofleaching,
contamination, degradation, aging) and of PTFE sleeves (Gary appreciates
their chemical inertness but does not recommend sleeves for static vacuum).
This tradeoff between disadvantages of joint grease and PTFE sleeves can be
overcome by Glindemann-PTFE-sealing rings, that are both chemically
inert and useful for high vacuum and static vacuum.
7. Opinion on
GLINDEMANN-PTFE-sealing rings by Jim J. Brien, Business Development and
Product Manager at Sigma-Aldrich company.
As a visitor at the 222nd ACS (American Chemical Society) National Meeting,
Chicago, in 2001, I saw a person walking on the floor with a Sigma-Aldrich
exhibitor badge, Mr. Jim Brien. I approached him and he tested my
product sample, a conical joint glass stopper with my PTFE sealing ring, in a
reagent tube with joint 14 mm. He noted, with surprise, that under amazingly
little sealing force, and with an "nice elastic" feeling, this PTFE ring becomes
transparent and visibly tight as if it was made of some soft material like grease. On the spot, Jim informed me
about his managerial function and decided to add my product to the Aldrich
catalogue.
Picture
extracted from the Kimble/Kontes Website in the year 2001 showing Kontes
product manager Mr. David Fenili promoting Glindemann rings on a pedestal.
Originally, his predecessor Mr. Al Grubert introduced the rings into the
Kontes catalogue after I demonstrated my product to him in 1998 during my
work at the University of British Columbia in Vancouver, Canada. I met David
Fenili and Al Grubert several times at exhibitions (ACS-Meetings and PITTCON
2001) were we distributed my product samples with great success at the
Kimble-Kontes booth. I sold the product to Kontes, and they sold it to
Aldrich from 2001 to 2009. Than we agreed that I sell the product directly
to Sigma-Aldrich.
I was glad to meet these influential and technically informed persons.
8. Handbook of Solvents, Volume 1.
George Wypych, ChemTec Publishing - William Andrew Publishing,
Toronto - New York - 2001. Chapter 4.4.3.1.1 Experimental equipment and
procedures for VLE-measurements (Vapor Liquid Equilibrium measurements).
Page 160 "(...)The following problems have to be solved during the
experiment: The equilibrium cell has to be sealed carefully to avoid any air
leakage over the complete duration of the measurements (to measure one
isotherm lasts about 14 days). Specially developed thin Teflon sealing
rings were preferred to grease. (...)".
Under these problematic
conditions, sealing the glass taper joint with joint grease was no optimal option because
absorbing solvent vapor would liquify the grease, resulting
in glass contamination by leached grease, and the risk of a large gas leak. Using PTFE sleeves (which are chemically inert
compared to grease) was no option, because no type of common PTFE sleeves
can prevent air leakage and hold static vacuum constant with an error of less than 1 mbar for
14 days. This problem was solved by using Glindemann PTFE sealing rings
that overcame the tradeoff between joint grease and PTFE sleeves.
9. Teaching book "Arbeitsmethoden in der Organischen
Chemie",
S. Hünig, G. Märkl, J. Sauer, P. Kreitmeier, A. Ledermann, 3.
Auflage, Lehmanns Media, 2014 (Seite 39), Citation: "...
Teflonhülsen ergeben mässig dichte Schliffverbindungen, die für einfache
Apparaturen ausreichend sind. Für höhere Ansprüche empfehlen sich dünne PTFE-Ringe (Glindemann-Ringe):
Diese Dichtringe werden auf den Kernschliff aufgezogen in die Schliffhülse
gesetzt und etwas angepresst. Wegen der kleinen Auflagefläche entsteht am
Dichtring ein hoher Druck, der das PTFE fließen lässt. Die Stelle mit dem
Dichtring erscheint bei richtiger Montage klar (wie bei einem gefetteten
Schliff). Die so gedichteten Schliffverbindungen besitzen eine hervorragende
Gas- und Vakuumdichtigkeit, lassen sich dabei aber leicht wieder trennen.
Sie haben sich insbesondere bei Reaktionen mit sehr luft- und
feuchtigkeitsempflindlichen Substanzen bewährt."
Translated: "Teflon sleeves result in moderately tight ground joints,
which are sufficient for simple apparatus. Thin PTFE rings (Glindemann rings) are recommended for higher demands:
These sealing rings are pulled onto the ground joint, placed in the ground
sleeve and pressed on slightly. Due to the small contact surface, high
pressure is generated on the sealing ring, which allows the PTFE to flow.
The spot with the sealing ring appears clear when installed correctly (like
a greased section). The ground joints sealed in this way have excellent gas
and vacuum tightness, but can be easily separated again. They have proven
particularly effective in reactions with substances that are very sensitive
to air and moisture."
Publications
citing Glindemann-rings (use for Schlenk
techniques)
- Example uses of
Glindemann-ring (PTFE sealing ring) for conical joint of Schlenk-flask with
air- and moisture-sensitive chemicals, to exclude grease and improve
cristallinization. Literature:
Chernichenko, K.
et al. Hydrogen activation by 2-boryl-N,N-dialkylanilines: a revision of
Piers’ ansa-aminoborane. Dalton Trans., 2012, 41, 9029-9032, DOI:
10.1039/C2DT30926B, see Electronic Supplementary Material file:
http://www.rsc.org/suppdata/dt/c2/c2dt30926b/c2dt30926b.pdf.
Chernichenko, K. et al. A frustrated-Lewis-pair approach to catalytic
reduction of alkynes to cis-alkenes. Nature Chemistry 5, 718–723 (2013),
doi:10.1038/nchem.1693, see Electronic Supplementary Material file:
http://www.nature.com/nchem/journal/v5/n8/extref/nchem.1693-s1.pdf.
Scott E. Denmark, Christopher R. Butler.
Vinylation with Inexpensive Silicon-Based Reagents: Preparation of
3-Vinyl-quinoline and 4-Vinylbenzophenone. Organic Syntheses, Vol. 86 (2009)
274-286.
Saleh et al. Chlorination of 1‑Carba-closo-dodecaborate and
1‑Ammonio-closo-dodecaborate Anions. Inorg. Chem. 2016, 55, 20, 10617-10627.
%20+Schliff%20Dichtring%20%20%20%20%20%20%20%20%20%2096%20dpi.JPG)
made off PTFE
(known as Teflon) on ground tapered glass joints has been developed.
Foto: Glindemann ring combined with Keck® joint clip
Foto:
Glindemann ring combined with Clipox® joint clip
Foto: 
Picture
extracted from the Kimble/Kontes Website in the year 2001 showing Kontes
product manager Mr. David Fenili promoting Glindemann rings on a pedestal.
Originally, his predecessor Mr. Al Grubert introduced the rings into the
Kontes catalogue after I demonstrated my product to him in 1998 during my
work at the University of British Columbia in Vancouver, Canada. I met David
Fenili and Al Grubert several times at exhibitions (ACS-Meetings and PITTCON
2001) were we distributed my product samples with great success at the
Kimble-Kontes booth. I sold the product to Kontes, and they sold it to
Aldrich from 2001 to 2009. Than we agreed that I sell the product directly
to Sigma-Aldrich.