Sciencemadness Discussion Board

OTC PTC?

fusso - 26-10-2019 at 17:20

What phase transfer catalysts are easy to obtain/make?

monolithic - 26-10-2019 at 18:09

TBAB (Tetrabutylammonium Bromide) can be purchased on Amazon.

Corrosive Joeseph - 26-10-2019 at 18:26

https://www.sciencemadness.org/whisper/viewthread.php?tid=73...


/CJ

clearly_not_atara - 26-10-2019 at 19:53

Orgsyn for trimethylamine from ammonium chloride + paraformaldehyde

http://www.orgsyn.org/demo.aspx?prep=CV1P0531

This can react with benzyl chloride (TCCA + toluene) in a suitable polar aprotic solvent such as acetone:

http://www.sciencemadness.org/talk/viewthread.php?tid=9343#p...

Issue is that trimethylammonium is very volatile. But it may react more easily than triethylamine due to lower steric hindreance.


fusso - 27-10-2019 at 15:20

Is choline too small for this?

clearly_not_atara - 27-10-2019 at 16:13

Choline is not a PTC, no. It's not just too small, it has a hydroxyl group which reduces its solubility in nonpolar phases.

wg48temp9 - 28-10-2019 at 04:21

Benzalkonium Chloride (frequently called BAC50), cetyltrimethylammonium bromide (cetrimide) and others is also available on ebay UK. .

I thought some rinse aids for dish washers contain surfactants which we call PTC but I was unable to confirm that from a quick check of a MSDS.

Mush - 29-10-2019 at 11:58

Quaternary Ammonium Compounds in Cleaning Products:Health & Safety Information for Cleaners and Supervisors

https://med.nyu.edu/pophealth/sites/default/files/pophealth/...

Watch out for these words on labels:
Benzalkonium chlorides

Names that end in “ammonium chloride”

Antibacterial
Antimicrobial


https://hpd.nlm.nih.gov/

Search results: Primary record found searching ammonium chloride as Ingredient.

Ammonium chloride

Search results: 49 other record(s) found searching ammonium chloride as chemical name fragment(s).

Dimethyl benzyl ammonium chloride
Alkyl(C12-18)dimethyl ethylbenzyl ammonium chloride
Quaternium-18 hectorite
Mixed dialkyl (C8-C10) dimethyl ammonium chloride
Alkyl(C12-16)dimethylbenzylammonium chloride
Benzethonium Chloride
Dimethyl ditallow ammonium chloride
Quaternium-18 bentonite
Cetrimonium chloride
Stearalkonium chloride
Dicetyldimonium chloride
Tallowtrimonium chloride
Olealkonium chloride
Polyquaternium-6
Soytrimonium chloride
Quaternium-18
Distearyldimonium chloride
Hydroxyethyl cetyldimonium chloride
Quaternium-24
Dioctyl dimethyl ammonium chloride
Didecyl dimethyl ammonium chloride
Alkyl dimethyl benzyl ammonium chloride
Polyoxypropylene methylethyl ammonium chloride
n-Alkyl (C12-C18) dimethyl benzyl ammonium chloride
Myristyl dimethyl benzyl ammonium chloride
Alkyl(C12-C14)dimethyl ethyl benzyl ammonium chlorides
Dodecyl dimethyl ammonium chloride
Alkyl (C10-C14) dimethyl benzyl ammonium chloride
Benzalkonium chloride
Dodecyl dimethyl ethylbenzyl ammonium chloride
Carnitine (L-form) hydrochloride
n-Alkyl(C14, 60%; C16, 30%; C12, 5%; C18, 5%) dimethylbenzyl ammonium chloride
n-Alkyl(C12, 68%, C14, 32%) dimethyl ethylbenzyl ammonium chloride
Alkyl(C12-18)dimethylethylbenzyl ammonium chlorides
Alkyl polyhydroxy-substituted ammonium chloride
Basic brown 16
Steartrimonium chloride
Didodecyldimethylammonium chloride
Quaternary ammonium compounds, cocoalkylbis(hydroxyethyl)methyl, ethoxylated, chlorides
Difethialone
Modified polyacrylate
Acetyl Hexapeptide-8
Panthenyl Triacetate
Acrylic acid, methacrylic acid polymer, sodium salt
Polymeric Terpenes
Prodiamine
Beta-Caryophyllene
C.I. Iron Oxides
Dipropylene glycol monomethyl ether

[Edited on 29-10-2019 by Mush]

fusso - 29-10-2019 at 12:29

Are all PTC surfactants?

clearly_not_atara - 29-10-2019 at 13:21

Yes but no -- a conventional "soapy" surfactant forms micelles, which are oriented nanospheres with a nonpolar interior and a polar exterior. A symmetrical ion like tetrabutylammonium will not form micelles in aqueous solution.

However, the literal definition of "surfactant" is just "reduces surface tension", so under this definition I think nearly all PTC are a little bit surfactant in that they lower surface tension. However, the surfactant property is often undesirable -- it promotes the formation of emulsions and foams -- which is why shorter, more symmetric PTC like TEBAC and TBAB are preferred in chemistry practice, while dimethylbenzyl-long-alkyl quats, with the usual head-tail structure and micelle formation property, are used for detergent purposes.

wg48temp9 - 30-10-2019 at 02:10

Quote: Originally posted by clearly_not_atara  
Yes but no -- a conventional "soapy" surfactant forms micelles, which are oriented nanospheres with a nonpolar interior and a polar exterior. A symmetrical ion like tetrabutylammonium will not form micelles in aqueous solution.

However, the literal definition of "surfactant" is just "reduces surface tension", so under this definition I think nearly all PTC are a little bit surfactant in that they lower surface tension. However, the surfactant property is often undesirable -- it promotes the formation of emulsions and foams -- which is why shorter, more symmetric PTC like TEBAC and TBAB are preferred in chemistry practice, while dimethylbenzyl-long-alkyl quats, with the usual head-tail structure and micelle formation property, are used for detergent purposes.


I think clearly_not_atara is correct there is more to PTCs than my understanding of simply assisting in making an emulsion which may be an incidental effect.

From:Attachment: solubilization-and-micellar-and-phase-transfer-catalysis-2005.pdf (441kB)
This file has been downloaded 337 times

[Edited on 10/30/2019 by wg48temp9]