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| Matt... |
 Posted: Thu Oct 22, 2009 9:04 am |
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Guest
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Chemistry folks (I am not a chemist),
In doing legal research, I have discovered US patents that describe a
certain procedure to be done "under nitrogen." For example,
"Diphenylphosphine (29.4 g, 158 mmol, 1 eq) was added instantly giving
a red coloration. The solution was heated at reflux under nitrogen for
17 hours."
What is involved in boiling something "under nitrogen" that is
different from simply boiling it?
Thank you, |
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| dlzc... |
| Posted: Thu Oct 22, 2009 9:55 am |
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Guest
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Dear Matt:
On Oct 22, 12:04 pm, Matt <matt.m... at (no spam) gmail.com> wrote:
[quote]Chemistry folks (I am not a chemist),
In doing legal research, I have discovered US
patents that describe a certain procedure to
be done "under nitrogen." For example,
"Diphenylphosphine (29.4 g, 158 mmol, 1 eq)
was added instantly giving a red coloration.
The solution was heated at reflux under nitrogen
for 17 hours."
What is involved in boiling something "under
nitrogen" that is different from simply boiling it?
[/quote]
The operation was performed under a nitrogen blanket, which requires
the environs above the boiling liquid to have nitrogen gas
(exclusively) present. The nitrogen is used as an inexpensive gas
that will displace oxygen, and not take part in contaminating the
target reaction.
Similar techniques are used in welding, keeping oxygen from damaging
the molten metals, while they get a chance to merge and cool. Most
commonly, argon is used in this case, although nitrogen is used if the
"area of work" is large.
In fact, the technique (nitrogen blanket) has been used to keep
chopped lettuce fresh for storage on a refrigerated shelf for long(er)
periods. (Of course the choice of gas may be pure oxygen in this
case.)
Patents can be invalidated by things as simply chosing a non-specified
"shield gas", should there be no disclaimer allowing other choices.
David A. Smith |
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| Bill Penrose... |
| Posted: Thu Oct 22, 2009 11:06 am |
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Guest
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On Oct 22, 12:23 pm, Dirk Bruere at NeoPax <dirk.bru... at (no spam) gmail.com>
wrote:
[quote]...The other joke I heard was that when a tech
kept being asked for "copious water" (as opposed to the normal kind) he
had a big bottle filled with water and a label which read: "Copious
Water - use sparingly".
[/quote]
Isn't that the form of holy water used by Coptic Christians?
DB |
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| Matt... |
| Posted: Thu Oct 22, 2009 11:15 am |
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Guest
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Thank you all for the helpful responses, notwithstanding the "crap
quality" of my question (note from my earlier post that I had this
question doing legal research for a client, and that I am not a
chemist).
If I am to understand fully - chemists will often use a stream of
nitrogen as a "blanket" on top of chemical reactions in order to
displace oxygen in the ambient air. The goal is to avoid an oxygen
reaction on top of whatever is boiling, similar to the ways welders
will manipulate the air around them to avoid problems with the
chemical makeup of the air. I guess my remaining questions, therefore,
are:
1) Is the real goal here to prevent contaminating the finished product
with whatever would result from boiling in an oxidized environment?
and
2) Is this mostly used as a general safety precaution, or is it
absolutely crucial to some procedures that they be done under nitrogen? |
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| Dirk Bruere at NeoPax... |
| Posted: Thu Oct 22, 2009 1:05 pm |
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Guest
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Matt wrote:
[quote]Chemistry folks (I am not a chemist),
In doing legal research, I have discovered US patents that describe a
certain procedure to be done "under nitrogen." For example,
"Diphenylphosphine (29.4 g, 158 mmol, 1 eq) was added instantly giving
a red coloration. The solution was heated at reflux under nitrogen for
17 hours."
What is involved in boiling something "under nitrogen" that is
different from simply boiling it?
Thank you,
[/quote]
Lack of an oxidizing atmosphere.
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show |
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| Mark Thorson... |
| Posted: Thu Oct 22, 2009 1:18 pm |
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Guest
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Dirk Bruere at NeoPax wrote:
[quote]
Matt wrote:
What is involved in boiling something "under nitrogen" that is
different from simply boiling it?
Lack of an oxidizing atmosphere.
[/quote]
If he doesn't understand "under nitrogen",
do you think he'll understand your explanation?
"Under nitrogen" means nitrogen gas is used
to purge the space above the boiling liquid
to exclude oxygen, presumably because some
component of the liquid or the vapor will
react with oxygen. This may done to prevent
a desirable chemical from being degraded,
or it may be done to avoid a fire or
explosion. |
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| Dirk Bruere at NeoPax... |
| Posted: Thu Oct 22, 2009 1:23 pm |
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Guest
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Mark Thorson wrote:
[quote]Dirk Bruere at NeoPax wrote:
Matt wrote:
What is involved in boiling something "under nitrogen" that is
different from simply boiling it?
Lack of an oxidizing atmosphere.
If he doesn't understand "under nitrogen",
do you think he'll understand your explanation?
"Under nitrogen" means nitrogen gas is used
to purge the space above the boiling liquid
to exclude oxygen, presumably because some
component of the liquid or the vapor will
react with oxygen. This may done to prevent
a desirable chemical from being degraded,
or it may be done to avoid a fire or
explosion.
[/quote]
Reminds me of a complaint I heard from a chem dept in the UK bemoaning
the crap quality of the students these days. They did not know what
"aqueous solution" meant. The other joke I heard was that when a tech
kept being asked for "copious water" (as opposed to the normal kind) he
had a big bottle filled with water and a label which read: "Copious
Water - use sparingly".
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show |
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| Dirk Bruere at NeoPax... |
| Posted: Thu Oct 22, 2009 2:24 pm |
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Guest
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dlzc wrote:
[quote]Dear Matt:
On Oct 22, 12:04 pm, Matt <matt.m... at (no spam) gmail.com> wrote:
Chemistry folks (I am not a chemist),
In doing legal research, I have discovered US
patents that describe a certain procedure to
be done "under nitrogen." For example,
"Diphenylphosphine (29.4 g, 158 mmol, 1 eq)
was added instantly giving a red coloration.
The solution was heated at reflux under nitrogen
for 17 hours."
What is involved in boiling something "under
nitrogen" that is different from simply boiling it?
The operation was performed under a nitrogen blanket, which requires
the environs above the boiling liquid to have nitrogen gas
(exclusively) present. The nitrogen is used as an inexpensive gas
that will displace oxygen, and not take part in contaminating the
target reaction.
Similar techniques are used in welding, keeping oxygen from damaging
the molten metals, while they get a chance to merge and cool. Most
commonly, argon is used in this case, although nitrogen is used if the
"area of work" is large.
In fact, the technique (nitrogen blanket) has been used to keep
chopped lettuce fresh for storage on a refrigerated shelf for long(er)
periods. (Of course the choice of gas may be pure oxygen in this
case.)
Patents can be invalidated by things as simply chosing a non-specified
"shield gas", should there be no disclaimer allowing other choices.
David A. Smith
[/quote]
So where does one purchase these blankets, and what are them made from?
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show |
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| Dirk Bruere at NeoPax... |
| Posted: Thu Oct 22, 2009 3:42 pm |
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Guest
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Matt wrote:
[quote]Thank you all for the helpful responses, notwithstanding the "crap
quality" of my question (note from my earlier post that I had this
question doing legal research for a client, and that I am not a
chemist).
If I am to understand fully - chemists will often use a stream of
nitrogen as a "blanket" on top of chemical reactions in order to
displace oxygen in the ambient air. The goal is to avoid an oxygen
reaction on top of whatever is boiling, similar to the ways welders
will manipulate the air around them to avoid problems with the
chemical makeup of the air. I guess my remaining questions, therefore,
are:
1) Is the real goal here to prevent contaminating the finished product
with whatever would result from boiling in an oxidized environment?
and
2) Is this mostly used as a general safety precaution, or is it
absolutely crucial to some procedures that they be done under nitrogen?
[/quote]
Generally nitrogen reacts with nothing. It's cheap and mostly inert.
Very few procedures would require nitrogen, rather than (say) a true
inert gas like Argon. [Which isn't actually totally inert but you need
some real evil stuff like Fluorine to make it do anything]
So generally the nitrogen is just there to fill the space and not do
anything.
BTW, something like Diphenylphosphine sounds like the sort of chemical
that would catch fire in air really easily.
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show |
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| dlzc... |
| Posted: Thu Oct 22, 2009 5:00 pm |
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Guest
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Dear Dirk Bruere at NeoPax:
On Oct 22, 1:24 pm, Dirk Bruere at NeoPax <dirk.bru... at (no spam) gmail.com>
wrote:
[quote]dlzc wrote:
Dear Matt:
On Oct 22, 12:04 pm, Matt <matt.m... at (no spam) gmail.com> wrote:
Chemistry folks (I am not a chemist),
In doing legal research, I have discovered US
patents that describe a certain procedure to
be done "under nitrogen." For example,
"Diphenylphosphine (29.4 g, 158 mmol, 1 eq)
was added instantly giving a red coloration.
The solution was heated at reflux under nitrogen
for 17 hours."
What is involved in boiling something "under
nitrogen" that is different from simply boiling it?
The operation was performed under a nitrogen
blanket, which requires the environs above the
boiling liquid to have nitrogen gas (exclusively)
present. The nitrogen is used as an inexpensive
gas that will displace oxygen, and not take part
in contaminating the target reaction.
Similar techniques are used in welding, keeping
oxygen from damaging the molten metals, while
they get a chance to merge and cool. Most
commonly, argon is used in this case, although
nitrogen is used if the "area of work" is large.
In fact, the technique (nitrogen blanket) has been
used to keep chopped lettuce fresh for storage
on a refrigerated shelf for long(er) periods. (Of
course the choice of gas may be pure oxygen in
this case.)
Patents can be invalidated by things as simply
chosing a non-specified "shield gas", should
there be no disclaimer allowing other choices.
So where does one purchase these blankets, and
what are them made from?
[/quote]
They are made by the Snuggy Corporation, and them's made from moler-
cules.
I just figured someone doing research needed the various inflections
of choosing an atmosphere for an operation other than "air".
David A. Smith |
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| dlzc... |
| Posted: Thu Oct 22, 2009 5:05 pm |
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Guest
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Dear Matt:
On Oct 22, 2:15 pm, Matt <matt.m... at (no spam) gmail.com> wrote:
....
[quote]1) Is the real goal here to prevent contaminating
the finished product with whatever would result
from boiling in an oxidized environment?
and
2) Is this mostly used as a general safety
precaution, or is it absolutely crucial to some
procedures that they be done under nitrogen?
[/quote]
Dirk's answer is not wrong, and it is not incomplete...
You can choose between:
1) yes
2) yes
.... or ...
1) it depends on the constituents, the desired reaction, and the
quality or amount of product desired.
2) it depends on the constituents, and (somewhat) on whether or not
you have other protective devices methods available.
Not that nitrogen blankets are terribly safe. They have killed
workers in the past.
David A. Smith |
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| Bill Penrose... |
| Posted: Thu Oct 22, 2009 7:40 pm |
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Guest
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On Oct 22, 2:15 pm, Matt <matt.m... at (no spam) gmail.com> wrote:
[quote]1) Is the real goal here to prevent contaminating the finished product
with whatever would result from boiling in an oxidized environment?
and
2) Is this mostly used as a general safety precaution, or is it
absolutely crucial to some procedures that they be done under nitrogen?
[/quote]
All of the above, depending on the situation. Also, nitrogen bubbling
is often used to remove gaseous products of a reaction, forcing the
reaction to go to completion.
DB |
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| Anonymous... |
| Posted: Thu Oct 22, 2009 10:46 pm |
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Guest
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[quote]Thank you all for the helpful responses, notwithstanding
the "crap quality" of my question (note from my earlier
post that I had this question doing legal research for a
client, and that I am not a chemist).
If I am to understand fully - chemists will often use a
stream of nitrogen as a "blanket" on top of chemical reactions
in order to displace oxygen in the ambient air. The goal
is to avoid an oxygen reaction on top of whatever is boiling,
[/quote]
1. It is always a stream but can be a static layer (blanket).
(Fill a balloon and connect it to the system.)
2. Modern commercial lab nitrogen is 99.999% pure and is also
very dry. Sometimes the N2 is used to keep moisture (from normal
humid air) out of the reaction.
3. Likewise, trace atmospheric CO2, should that be a problem.
4. It has already been noted by Dirk that N2 is not inert but
only "almost inert". Yep. You need to know your chemistry
to decide if N2 is 'inert enough' under those conditions.
5. Many of you realize that this lawyer guy is probably
charging his client $400-$700 per hour (in 6 minute increments)
to surf the web and pick our brains for an answer while many
of those who KNOW the answers are unemployed or underemployed
and earning squat.
[quote]1) Is the real goal here to prevent contaminating the finished
product with whatever would result from boiling in an oxidized
environment?
[/quote]
Not necessarily. Air (oxygen) or water (humidity) might simply
be destroying a catalyst: the reaction stops, party over,
but no contamination. It could be prematurely stopping
the propagation step in a polymerization reaction. Etc.
What's the reaction? What's the patent number? We'll tear it
apart for you. |
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| George Orwell... |
| Posted: Fri Oct 23, 2009 12:23 am |
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Guest
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Oops. Typos.
[quote]1. It is always a stream but can be a static layer (blanket).
(Fill a balloon and connect it to the system.)
[/quote]
It is NOT always a stream but can be a static layer ...
[quote]What's the reaction?
"Diphenylphosphine (29.4 g, 158 mmol, 1 eq) was added
instantly giving a red coloration. ..."
[/quote]
Although Wikipedia doesn't say so, other sources say that
Ph2PH is pyrophoric = ignites spontaneously in air (due
to the oxygen O2 + Ph2PH ----> Ph2POOH) and I would always
handle Ph2PH under N2 for safety as well as to make sure
it did what it was supposed to do in the reaction and not
just form Ph2POOH.
Il mittente di questo messaggio|The sender address of this
non corrisponde ad un utente |message is not related to a real
reale ma all'indirizzo fittizio|person but to a fake address of an
di un sistema anonimizzatore |anonymous system
Per maggiori informazioni |For more info
https://www.mixmaster.it |
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| Dirk Bruere at NeoPax... |
| Posted: Fri Oct 23, 2009 8:17 am |
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Guest
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dlzc wrote:
[quote]Dear Matt:
On Oct 22, 2:15 pm, Matt <matt.m... at (no spam) gmail.com> wrote:
...
1) Is the real goal here to prevent contaminating
the finished product with whatever would result
from boiling in an oxidized environment?
and
2) Is this mostly used as a general safety
precaution, or is it absolutely crucial to some
procedures that they be done under nitrogen?
Dirk's answer is not wrong, and it is not incomplete...
You can choose between:
1) yes
2) yes
... or ...
1) it depends on the constituents, the desired reaction, and the
quality or amount of product desired.
2) it depends on the constituents, and (somewhat) on whether or not
you have other protective devices methods available.
Not that nitrogen blankets are terribly safe. They have killed
workers in the past.
David A. Smith
[/quote]
That is actually quite interesting.
It is a quick and painless (maybe even enjoyable?) way to die.
Unconsciousness occurs in less than 30 seconds, with no warning signs
apart from muddled thinking and euphoria. You'd be brain dead after
about 3 min.
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show |
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