N,N-Dibenzoyl­ferrocenecarboxamide

In the title compound, [Fe(C5H5)(C20H14NO3)], the cyclo­penta­dienyl rings deviate by 9.3 (2)° from an eclipsed conformation, defined by C—Cg 1—Cg 2—C pseudo-torsion angles ranging from 8.8 (1) to 9.85 (1)°. The coordination at the N atom is slightly pyramidal, as indicated by the angular sum around it of 352.6°. The amide group is inclined at 17.86 (9) and 27.27 (11)° with respect to the aromatic rings. In the crystal, mol­ecules are linked by one C—H⋯O hydrogen bond and one C—H⋯π inter­action into a two-dimensional framework parallel to the b axis

Adsorption of reactive dye on activated carbon: kinetic study and influence of initial dye concentration

Although many of the dyes used in dyeing process are not toxic, dyed effluents have harmful and negative aesthetic and biological effect on water systems, and therefore dyes should be removed from wastewaters. This paper deals with isothermal adsorption of Reactive Black 5 dye on commercial activated carbon. Batch adsorption study was carried out in different periods, from 30 minutes to 16 hours, when equilibrium was reached. Results show exponential lowering of dye concentration after adsorption, from 500 mg dm-3 to 118 mg dm-3 at equilibrium. In order to investigate the mechanism of adsorption kinetic studies have been performed, and pseudo-second order kinetic model better describes adsorption process of this system. The aim of this work was also to compare influence of initial dye concentration on the adsorption process; percentage of adsorbed dye at equilibrium for initial dye concen-tration c0 = 300 mg dm-3 is for 18 % bigger than that of c0 = 500 mg dm-3

Adsorption of reactive dye on activated carbon: kinetic study and influence of initial dye concentration

Although many of the dyes used in dyeing process are not toxic, dyed effluents have harmful and negative aesthetic and biological effect on water systems, and therefore dyes should be removed from wastewaters. This paper deals with isothermal adsorption of Reactive Black 5 dye on commercial activated carbon. Batch adsorption study was carried out in different periods, from 30 minutes to 16 hours, when equilibrium was reached. Results show exponential lowering of dye concentration after adsorption, from 500 mg dm-3 to 118 mg dm-3 at equilibrium. In order to investigate the mechanism of adsorption kinetic studies have been performed, and pseudo-second order kinetic model better describes adsorption process of this system. The aim of this work was also to compare influence of initial dye concentration on the adsorption process; percentage of adsorbed dye at equilibrium for initial dye concen-tration c0 = 300 mg dm-3 is for 18 % bigger than that of c0 = 500 mg dm-3

An Efficient Synthesis of Pyridoxal Oxime Derivatives under Microwave Irradiation

Quaternary salts of pyridoxal oxime have been synthesized by the quaternization of pyridoxal oxime with substituted phenacyl bromides using microwave heating. Microwave-assisted rapid synthesis was done both in solvent (acetone) and under solvent-free conditions. Good to excellent yields (58%94%) were obtained in acetone in very short reaction times (35 min) as well as in the solvent-free procedure (42%78%) in very short reaction times (710 min) too. Effective metodologies for the preparation of pyridoxal oxime quaternary salts, having the advantagies of being eco-friendly, easy to handle, and performed in shorter reactions time are presented. The structure of compound 7, in which a 4-fluorophenacyl moiety is bonded to the pyridinium ring nitrogen atom, was unequivocally confirmed by the single-crystal X-ray diffraction method

Synthesis and Structural Characterization of the 5-(2- Haloethyl)pyrimidines - Hydrogen-Bonded chains in a-(1- Carbamyliminomethylene)-g-Butyrolactone

Three novel 5-(2-haloethyl)pyrimidine derivatives were synthesized and characterized by 1H-NMR, 13C-NMR, MS, IR spectra and elemental analysis. Iodine and chlorine atoms in the C-5 side chain were introduced by reaction of 5-(2- hydroxyethyl)pyrimidine with hydroiodic acid and phosphoryl chloride, respectively. The structure of the intermediate a-(1-carbamyliminomethylene)-g-butyrolactone was determined by X-ray crystal structure analysis. The molecule deviates very slightly from planarity. Three NHO hydrogen bonds link the molecules into one-dimensional chains of edge-fused rings

Utjecaj kompleksacije piroksikama s ciklodekstrinima na oblikovanje gela

The aim of this work was to evaluate the role of cyclodextrins in topical drug formulations. Solid piroxicam (PX) complexes with beta-cyclodextrin (beta-CD) and randomly methylated beta-cyclodextrin (RAMEB) were prepared by freeze-drying and characterized using differential scanning calorimetry (DSC), X-ray powder diffractometry (XRPD), Fourier transform infrared spectroscopy (FTIR) and near infrared spectroscopy (NIR). A physical mixture of PX and cyclodextrins was characterized by enhanced dissolution properties compared to the dissolution profile of the pure drug due to in situ complex formation. Formation of the PX-cyclodextrin inclusion complex additionally improved the drug dissolution properties. Influence of CDs on drug permeation from the water dispersion and the prepared hydroxypropyl methylcellulose (HPMC) gels was investigated. Permeation of the drug involved three consecutive processes: dissolution of the solid phase, diffusion across the swollen polymer matrix and drug permeation through the membrane. Complexation increased PX diffusion by increasing the amount of diffusible species in the donor phase. Slower drug diffusion through the HPMC matrix was the rate limiting step in the overall diffusion process. Possible interaction between the hydrophilic polymer and cyclodextrin may result in physicochemical changes, especially in a change of rheological parameters.Svrha rada bila je ispitati utjecaj kompleksacije piroksikama s ciklodekstrinima na oblikovanje pripravaka za topičku primjenu lijeka. Kompleksi piroksikama s β- i nasumično metiliranim β-ciklodekstrinom u krutom stanju pripremljeni su metodom sušenja smrzavanjem i karakterizirani su diferencijalnom pretražnom kalorimetrijom, difrakcijom X-zraka na prahu, infracrvenom spektroskopijom s Fourierovim transformacijama, te spektroskopijom u niskom infracrvenom području. Fizička smjesa lijeka s ciklodekstrinima karakterizirana je poboljšanom topljivošću u usporedbi sa čistim lijekom zbog stvaranja kompleksa in situ. Kompleksacija piroksikama sa ciklodekstrinima dodatno je poboljšala topljivost lijeka u liofiliziranom kompleksu. Ispitan je utjecaj ciklodekstrina na permeaciju lijekova iz vodenih disperzija i pripremljenih gelova s hidroksipropil metilcelulozom. Permeacija lijekova uključuje više uzastopnih procesa: otapanje krute faze, difuziju lijeka kroz izbubreni polimerni matriks, te difuziju lijeka kroz polupropusnu membranu. Kompleksacija piroksikama s ciklodekstrinima povećala je difuzibilnost lijeka uslijed porasta količine lijeka raspoloživog za difuziju. Difuzija lijeka kroz izbubreni polimerni matriks hidroksipropil metilceluloze pokazala se ključnim procesom koji određuje ukupnu difuziju lijeka. Interakcija hidrofilnog polimera s ciklodekstrinima utjecala je na fizikalno-kemijska svojstva gela, posebice na reološke parametere

Utjecaj kompleksacije piroksikama s ciklodekstrinima na oblikovanje gela

The aim of this work was to evaluate the role of cyclodextrins in topical drug formulations. Solid piroxicam (PX) complexes with beta-cyclodextrin (beta-CD) and randomly methylated beta-cyclodextrin (RAMEB) were prepared by freeze-drying and characterized using differential scanning calorimetry (DSC), X-ray powder diffractometry (XRPD), Fourier transform infrared spectroscopy (FTIR) and near infrared spectroscopy (NIR). A physical mixture of PX and cyclodextrins was characterized by enhanced dissolution properties compared to the dissolution profile of the pure drug due to in situ complex formation. Formation of the PX-cyclodextrin inclusion complex additionally improved the drug dissolution properties. Influence of CDs on drug permeation from the water dispersion and the prepared hydroxypropyl methylcellulose (HPMC) gels was investigated. Permeation of the drug involved three consecutive processes: dissolution of the solid phase, diffusion across the swollen polymer matrix and drug permeation through the membrane. Complexation increased PX diffusion by increasing the amount of diffusible species in the donor phase. Slower drug diffusion through the HPMC matrix was the rate limiting step in the overall diffusion process. Possible interaction between the hydrophilic polymer and cyclodextrin may result in physicochemical changes, especially in a change of rheological parameters.Svrha rada bila je ispitati utjecaj kompleksacije piroksikama s ciklodekstrinima na oblikovanje pripravaka za topičku primjenu lijeka. Kompleksi piroksikama s β- i nasumično metiliranim β-ciklodekstrinom u krutom stanju pripremljeni su metodom sušenja smrzavanjem i karakterizirani su diferencijalnom pretražnom kalorimetrijom, difrakcijom X-zraka na prahu, infracrvenom spektroskopijom s Fourierovim transformacijama, te spektroskopijom u niskom infracrvenom području. Fizička smjesa lijeka s ciklodekstrinima karakterizirana je poboljšanom topljivošću u usporedbi sa čistim lijekom zbog stvaranja kompleksa in situ. Kompleksacija piroksikama sa ciklodekstrinima dodatno je poboljšala topljivost lijeka u liofiliziranom kompleksu. Ispitan je utjecaj ciklodekstrina na permeaciju lijekova iz vodenih disperzija i pripremljenih gelova s hidroksipropil metilcelulozom. Permeacija lijekova uključuje više uzastopnih procesa: otapanje krute faze, difuziju lijeka kroz izbubreni polimerni matriks, te difuziju lijeka kroz polupropusnu membranu. Kompleksacija piroksikama s ciklodekstrinima povećala je difuzibilnost lijeka uslijed porasta količine lijeka raspoloživog za difuziju. Difuzija lijeka kroz izbubreni polimerni matriks hidroksipropil metilceluloze pokazala se ključnim procesom koji određuje ukupnu difuziju lijeka. Interakcija hidrofilnog polimera s ciklodekstrinima utjecala je na fizikalno-kemijska svojstva gela, posebice na reološke parametere

Adsorpcija reaktivnog bojila na aktivnom ugljenu: kinetika i utjecaj početne koncentracije bojila

Iako mnoga bojila koja se koriste u procesu bojadisanja tekstila nisu toksična, obojene otpadne vode imaju štetan i negativan estetski i biološki učinak na vodene sustave, pa se zbog toga bojila trebaju ukloniti iz otpadnih voda. U ovom radu provedena je izotermna adsorpcija bojila Reactive Black 5 na komercijalnom aktivnom ugljenu. Adsorpcija je provedena šaržnim postup-kom u vremenskom razdoblju od 30 minuta do 16 sati, kada je postignuta ravnoteža. Rezultati pokazuju eksponencijalno smanjenje koncentracije bojila nakon adsorpcije, od 500 mg dm-3 do 118 mg dm-3 u stanju ravnoteže. Kako bi se istražio mehanizam kinetike adsorpcije provedene su kinetičke studije koje su pokazale da kinetički model pseudo-drugog reda bolje opisuje proces adsorpcije ovog sustava. Cilj ovog rada bio je također i usporediti utjecaj početne koncentracije bojila na proces adsorpcije; postotak adsorbiranog bojila u stanju ravnoteže za početnu koncentraciju bojila c0 = 300 mg dm-3 je za 18 % veći od onog za c0 = 500 mg dm-3