Chemada Articles


Influence of ionic liquid content on properties of dense polymer membranes

European Polymer Journal, Volume 45, Issue 3, Pages 813-819
M. Kohoutová, A. Sikora, Š. Hovorka, A. Randová, J. Schauer, M. Tišma, K. Setničková, R. Petričkovič,
S. Guernik, N. Greenspoon and P. Izák
Pervaporation was used for removal of butan-1-ol from its 5 wt.% of aqueous solution, at which the concentration of Clostridium acetobutylicum starts to decrease. The polydimethylsiloxane (PDMS) membrane containing 0, 10, 20 or 30 wt.% of benzyl-3-butylimidazolium tetrafluoroborate ([BBIM][BF4]) ionic liquid was used. Differential scanning calorimetry measurements showed that PDMS-[BBIM][BF4] membranes (though optically homogeneous) contained PDMS and [BBIM][BF4] phases. Pervaporation selectivity increased and total flux through membranes raised moderately with an increased content of [BBIM][BF4] in PDMS-[BBIM][BF4] membranes. Hence, immobilization of a proper ionic liquid in a membrane results in the creation of pervaporation membranes, effective in the removal of alcohol from fermentation broths. ..


CleaR brines as enviroment electrophilic aromatic

Speciality Chemicals Magazine, July/August 2007
Dr Nurit Kornberg of ICL-IP and Dr Noam Greenspoon of Chemada Fine Chemicals

The potential of clear brines as novel and convenient reaction medium for a variety of electrophonic aromatic substitutions has been demonstrated. As described above, aqueous solutions of ZnBr2 have been used successfully for the halogenations of a variety of deactivated aromatics. Selectivities as well as reaction rates were enhanced by the use of appropriate additives.
Similarly, brine-based reaction media were also employed for the alkylation of aromatic rings with aliphatic or aromatic alkenes and for the acylation of aromatic compounds. In all the cases described, dear brines replaced known Lewis acid catalysts, such as AICI3, while functioning as both solvent and catalyst.
Because of their intrinsic recyclability, clear brines have proven to be a selective and environmentally friendly reaction medium; a viable green alternative to harmful wasteful and toxic Lewis acid reagents and organic solvents in a variety of industrially important organic processes..


A novel system consisting of Rh–DuPHOS and ionic liquid for asymmetric hydrogenations

Chem. Commun., 2001, 2314-2315
Silvina Guernik, Adi Wolfson, Moti Herskowitz, Noam Greenspoon and Shimona Geresh
The ionic liquid [bmim][PF6] was found to provide extra stability to the air-sensitive chiral catalyst Rh–MeDuPHOS in asymmetric hydrogenation of enamides ...

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