Catalizadores

Ácidos inorgánicos fuertes: HCl, H2SO4, H3PO4

Ácidos orgánicos: AMS, APTS

Ácidos de Lewis: BF3, oxalato de zinc, AlCl3, alcóxidos de titanio, estaño y zirconio

Ácidos heterogéneos: zeolitasnaturales y modificadas, resinas de intercambio catiónico

Zeolitas (Heterogéneo)

Con el fin de expulsar el agua formada, la hidrofobicidad de la red de zeolita se espera que sea un parámetroimportante.

Orden de actividad:
Nb2O5 < H-ZSM-5 < Amberlyst-15 < Cs2:5 ̴ (SO4)2- /ZrO2 ≪ H-Nafion

The high activity of the perfluorosulfonic resin HNafion is striking. The swelling ofthis material, and hence the accessibility of the acid sites, strongly depend on the solvent. Mixtures of water and lower alcohols are almost the only solvents capable of dissolving Nafion pelletsBF3 (boron trifluoride)http://www.inorganics.basf.com/p02/CAPortal/en_GB/portal/Bortrifluorid_und_Bortrifluoridkomplexe/content/Produktgruppen/Borane_und_andere_Borverbindungen/Bortrifluorid_und_Bortrifluoridkomplexe/Bortrifluorid_und_Bortrifluoridkomplexe

Usado principalmente para la alquilación de benceno con cloruro de bencilo. Corrosivo y muy tóxico. Incompatible con agua, ya que produceuna reacción exotérmica.

BF3 can react with common solvents containing atoms of oxygen, sulfur, nitrogen, phosphorus, etc… to form complexes in which the BF3 content is usually between 20 and 65%w/w, depending of the solvent, such as phenol, dihydrate, diethylether, acetic acid, methanol, dioxane…

Boron trifluoride as well as its addition compounds can be employed as catalysts or cocatalystsin numerous syntheses in the most varied fields of organic chemistry, e.g. in reactions such as:
* oligomerization and polymerization (e.g. synthesis of high-grade lubricants and resins) *alkylation * acylation * carbonylation * carboxylation * isomerization * rearrangement * addition and condensation. |
They are also used as:
* doping components for semiconductors and...