The Baylis-Hillman reactions of various aryl aldehydes with methyl vinyl ketone at temperatures below -20C using Lewis acids such as titanium (IV) chloride, boron (III) chloride or zirconium (IV) chloride in the presence of a catalytic amount of selected amines used as a Lewis bases afford the chlorinated compounds 1 as the major product in very high yields. Acrylonitrile can also undergo the s...

tin(ii)-ion-selective electrode consisting of dibenzo-18-crown-6 (db18c6) as an ionophore inpvc matrix was developed. the influences of membrane composition, selectivity, response time,reversibility and temperature on the electrode performance were investigated. the electrodeshowed a near nernstian response for sn2+ ions over a concentration range from 1.0× 10-6 – 1.0× 10-2 m with a slope of 27...

colloids are small suspended particles in water which can not be settled or removed naturally due to their light weight and stability. these particles pose some degree of stability and cause water turbidity. there are some concerns regarding colloid removal efficiency in water treatment plants of iran. in this study, the effectiveness of aluminium sulfate and poly-aluminum chloride was evaluate...

introduction: colloidal materials and suspended solids cause turbidity in water. to remove turbidity, clarification method is used that includes processes of coagulation, flocculation, and sedimentation. due to the long duration of coagulation process, coagulant aids are applied. despite the favorable efficiency of synthetic polyelectrolytes as a coagulant aid, due to their harmful effects on h...

this paper focuses on the effects of the addition of an ionic liquid, 1-allyl-3-butylimidazilium bis(trifluoromethane sulfonyl)imide ([abim]tfsi), which has a high affinity for benzene, into the poly(vinyl chloride) (pvc) membrane on the pervaporation characteristics of the removal of benzene from aqueous solutions of dilute benzene. when aqueous solutions of 100～500 ppm benzene were permeated ...

Bis(imino)phenoxide complexes of zirconium possess spectacular reactivity towards the solvent-free polymerization of cyclic ester monomers and lactides. Polymerization of lactide is living and the resulting product has exceptionally high number average molecular weights (Mn). Polymerization of β-butyrolactone gives syndiotactic poly(3-hydroxybutyrate) with good Mn and molecular weight distribut...

Rhus laccase was isolated and purified from acetone powder obtained from the exudates of Chinese lacquer trees (Rhus vernicifera) from the Jianshi region, Hubei province of China. There are two blue bands appearing on CM-sephadex C-50 chromatography column, and each band corresponding to Rhus laccase 1 and 2, the former being the major constituent, and each had an average molecular weight of ap...

The monomeric title zirconium(IV) compound, [Zr(C(12)H(21)N(2)Si)(2)Cl(2)], was prepared by the metathetical reaction of [LiN(SiMe(2)NMe(2))(2,6-Me(2)C(6)H(3))](2) with zirconium tetra-chloride. The Zr(IV) atom is N,N'-chelated by the N-silylated anilido ligand. Along with two Cl atoms, the six-coordinated Zr(IV) atom demonstrates a highly distorted octa-hedral geometry. The two ligands around ...

mixing conditions of nbr/pvc nanocomposites such as mixing temperature, rotor speed and mixing time are determining parameters in rheological, mechanical and morphological properties of the compound. three levels were chosen for each parameter using design expert software via box-behnken method. the nanocomposite samples were melt-mixed in brabender internal mixer. the effect of various mixing ...