Bolt - 18-11-2007 at 22:50
I could buy a phase transfer catalyst from a lab supply, but I'd rather not.
I saw references to PTC being in different types of softener and conditioners. So I UTFSE here (with no luck) and at the Household Products Database
(with better luck) and came up with quite a few products that contained some kind of a PTC (often a quaternary ammonium salt, which is what I'd like
for my reaction).
For example:
http://householdproducts.nlm.nih.gov/cgi-bin/household/brand...
Now, I imagine that the amount of PTC in that is very small... even though the MSDS lists it as 50% of the active ingredients.
Does anybody have any guidance about where to look (maybe a specific product or even a different type of product altogether) for a PTC?
It would be even better even somebody could link to / post a write up of isolating or using an OTC PTC... I wouldn't even know how to begin with an
'easy' isolation.
guy - 18-11-2007 at 23:33
Pool algaecide has a lot of quat salts. They also add a dye though.
MagicJigPipe - 19-11-2007 at 18:23
There's lots of products with (it seems) only water and Quat Ammonium salts. I got a whole bunch of 25% QuatAmm? salt solution at a resturant I used
to work at. We used it for sanitizing dishes. I mean, I have gallons of this stuff just sitting around, longing for a purpose.
I do, however, occasionally dilute it with ethanol/water to use as homemade Lysol.
auto115186 - 1-2-2008 at 04:15
Dragging this topic back up from the dead! 
We found a synthesis for tetrabutyl ammonium salt PTCs that only seems to need two reagents, n-butylbromide and tributylamide. We were curious whether
these could be easily found in anything or perhaps synthesized at home.
We know hydrocarbons can be halogenated with UV light, but remember this being a somewhat explosive synthesis when we carried it out. Would it be
possible to bubble butane through HCl / HBr / HI and have it make a single addition to the butane in a safe manner? Perhaps using a catalyst. When we
saw the halogenation being carried out, it was in a sealed plastic bottle for some reason and the bottle popped when illuminated with UV from a
normal, but bright and close by, light source. We're unsure whether or not the reaction had to be contained in this manner or if it was simply a
demonstration of the rapid attack. If it were the latter, would it be feasible to just bubble butane into a flask of the appropriate acid and
illuminate it with UV to catalyse the halogenation? That'd be easy.
Could we;
use a chlorine generator to provide a halide, fit a flask with a reflux condenser, vent the condenser through some alkaline to neutralise any escaping
chlorine, then UV expose the flask as we blow butane and chlorine in and hope the resulting haloalkane rains down from the condenser.
It would be ideal if the subsitution position could be controlled, but expect that it will primarily be on the end carbon anyway, perhaps controllable
by temperature and we can separate the resulting mess with distillation.
The tribuytlamine we're not so sure about. How might one go about making this?
[Edited on 1-2-2008 by auto115186]
[Edited on 1-2-2008 by auto115186]
[Edited on 1-2-2008 by auto115186]
sparkgap - 1-2-2008 at 05:52
"we can separate the resulting mess with distillation."
- not very likely. the halogenation products have close boiling points with each other.
"The tribuytlamine we're not so sure about. How might one go about making this?"
- you essentially end with the problem of making 1-bromobutane.
++++++++++++
A procedure might be to procure 1-butanol and react with hydrogen bromide under acid catalysis. You can search around for details.
Sourcing 1-butanol from common stuff now becomes your problem.
sparky (~_~)
Nerro - 1-2-2008 at 06:25
Just out of curiosity, would soap work?
not_important - 1-2-2008 at 07:00
Ordinary soaps would drag the cations into the organic phase, while normally you want to drag the anions into the organic phase.
Soaps cap help in getting good dispersion of the phases, provided the reactants don't do in the soap itself as acidic reaction conditions would.
Nicodem - 1-2-2008 at 13:54
Quat phase transfer catalysts are available as antiseptics (didecyldimethylammonium chloride is one of the commonest).
Fabric softeners in most cases do not work for PTC use since they are made of very long aliphatic chains and tends to form myceles instead of
transferring anions.
Tetrabutylammonium salts are quite cheap and available. Preparing them from other chemicals would be more costly and time consuming than just buying
them. The only exception is probably benzyltriethylammonium chloride since Et3N and BnCl are ubiquitous, so no need to buy them.
chemrox - 2-2-2008 at 03:36
polypropylene glycol shows up in alot of OTC products ... automotive supplies, etc. not all PTCs are quat salts
auto115186 - 2-2-2008 at 04:54
"- not very likely. the halogenation products have close boiling points with each other."
That puts a crimp on an otherwise damn fine plan! Well maybe not, halogenation
is all coming back to me now, like the way primary carbon products aren't the major output. So it's actually not a particularly great plan, but it was
exciting while it lasted.
Quat phase transfer catalysts are available as antiseptics (didecyldimethylammonium chloride is one of the commonest).
As someone already suggested pool algeacides, I had a look at them and some patents for them and, from memory, I think quite a few of them use
didecyldimethylammonium.
Tetrabutylammonium salts are quite cheap and available. Preparing them from other chemicals would be more costly and time consuming than just
buying them.
Indeed, although I don't have an account with any lab suppliers, so I can't pick any up from there. Have you seen TBA salts anywhere else? I've been
googling and emailing for literally hours so I'm either not hitting on the correct words or it's not there.
polypropylene glycol shows up in alot of OTC products ... automotive supplies, etc. not all PTCs are quat salts
Have you ever experimented with using Polyprop Glycol in place of TBA salts, do they perform similarly?
[Edited on 2-2-2008 by auto115186]
LSD25 - 2-2-2008 at 15:37
Some of the more interesting PTC's are available in OTC guises, top of this list would have to be quinine which is indicated for
stereo/enantiospecific PTC type alkylation reactions (with benzylation of course). Quinine sulfate is the active ingredient in tonic water, and upon
basification forms an insoluble freebase.
Certain members of the Aliquat series are found used in sterilization for industrial/agricultural use - also look for didecyl dimethyl ammonium
halide(x) - which is indicated as a water soluble replacement PTC for Aliquat 336 by this site {http://www.phasetransfer.com/suppliers/dec2me2ncl.htm}
and which is extremely widely used in Agriculture (30% solution x hundreds of liters).
Finally, look at soap/shampoo suppliers (the ones who supply home industry), they often have useful things like triethanolamine, EDTA,
n,n-dimethylethanolamine, malic acid (in large quantities), boric acid, KOH, glycols (pure) and normally a range of cationic/anionic/etc. surfactants
and solubilisers. They also provide a range of clear & amber glass bottles which come in useful.
Some of them are very expensive so shop around.
not_important - 3-2-2008 at 01:46
Poly----ene oxides/glycols function closer to crown ethers than quat salts. They are non-ionic, and mostly interact with cations.
They useful in their own right, as they can function both as co-solvents and may serve to keep metallic catalysts from clumping into larger, less
active, conglomerates.
Nicodem - 3-2-2008 at 02:57
I think this thread is already loosing its point. The concept of "phase transfer catalyst" is too wide to treat it the way it is done here. We can not
talk about the interchangeability of PTC's since they are generally not particularly interchangeable. The choice depends on the system on which they
are to be applied. In this thread nobody ever described any system on which they are to be applied, so all the guessing which of the many PTCs
available in the commercial products is suitable, is completely pointless. To reiterate:
If someone needs tetrabutylammonium bromide he can buy it from the chemical suppliers – it's not labeled "T", "T+" nor is it
regulated by any law and regulation, so any private citizen can just order it from the local representative of his favorite chemical suppliers.
Benzyltriethylammonium chloride is easily prepared from available chemicals (I think Garage chemist once posted its preparation).
Didecyldimethylammonium chloride works great as PTC in certain applications, like alkylations of phenols and similar (as far as I
know, it is available as antiseptic in just about every country of the world).
The benzyltrimethylammonium chloride available in pool algaecides is a bit less efficient for liquid/liquid interphase anion transfer
since less soluble in nonpolar phases, but I guess it would work to some extent for solid/liquid systems.
Fabric softeners are pretty much useless (except for the systems where their emulsion forming ability is of advantage). But like
mentioned, efficiency depends on the system used. Just consider that, for example 3 mol% of a fabric softener, can easily weight more than the organic
substrate (thanks a lot for such "catalytic amounts"!). They also have this annoying tendency to get "poisoned" by forming insoluble crap with certain
ions and insolubles.
Polyethylene glycols (PEG) are not phase transfer catalysts! I know they are often propagandized that way, but they are just
cosolvents, very efficient at solvating both the potassium salts and the organic substrate (sodium and other salts can also be used, but potassium
salts work best). They do not transfer anions from one phase to the other, but promote the reaction by making it homogenous. As such, they can only be
applied to appropriate systems.
Crown ethers can be considered PTCs on the condition that a potassium salt of the nucleophile is used. They can indirectly
carry the anion from the solid phase to the nonpolar phase. They do this by chelating the K<sup>+</sup> cation and carrying it into the
nonpolar phase, thus a counterion (anion) is also forced into the nonpolar phase by means of electrostatic force. Crown ethers can however only be
used in the absence of aqueous phase (the solid potassium salt is generally stirred in the acetonitrile or other solvent in the presence of the crown
ether and the organic substrate). They are extremely inefficient at dealing with water solvated ions. They are thus catalysts for solid/liquid
interfaces – unlike quat type PTCs which work for both solid/liquid and liquid/liquid interphase anion transfer.
Quinine is not a PTC - only its N-alkyl derived quats are!
Anionic soaps are not PTCs, they can not carry the anionic nucleophiles into the nonpolar phase!
[Edited on 3/2/2008 by Nicodem]
chemrox - 3-2-2008 at 11:59
Last time I looked the only criterion for a PTC was that it facilitated reaction between materials in two diferent phases. From what I've read
polyethylene glycols, crown ethers and quat salts all achieve this under certain circumstances. I think the misconception this thread has labored
under, and that Nicdem has correctly pointed to, is the idea that PTC's are interhcangeable. They are not. Some quat salts may be, for some
purposes; some crown ethers may be interchangeable for some purposes and sometimes these may interchange with PPG's. It's all very system specific so
you can't go out looking in the pool supplies and auto parts stores for a generic PTC. This is one more case where lack of specifics has lead to
wasted bandwidth and maybe this is the worthwhile lesson here so thanks to Nicodem for pointing it out. I suggest we terminate it.
auto115186 - 6-2-2008 at 04:13
Thanks for all the replies, interesting read.
I was reading a patent that was describing how it's easier to make TBAI than TBAB, and I think TBAC is more expensive than both from memory. The
patent mentioned how it used to be normal to make TBAI first and then convert it to TBAB.
Would it be possible to easily strip the bromide and produce TBAI? I have some TBAB and iodine spare, but the supplier doesn't carry any small amounts
of the TBA iodide salt.
[Edited on 6-2-2008 by auto115186]