Gheorghe Dehelean

Mixed Quaternary Ammonium and Phosphonium Salts Bound to Macromolecular Supports for Removal Bacteria from Water

This paper deals with synthesis and characterization of mixed quaternary ammonium and phosphonium salts grafted on macromolecular supports by polymer-analogous trans-quaternization reactions. The degrees of functionalization with quaternary mixed ammonium and phosphonium groups are relatively high, ranging from 0.09 to 1.285 mmoles of functional groups/gram of copolymer, ensuring a sufficient concentration of active centers per unit mass of copolymer and being well suited for application as antibacterial agents.

Synthesis of Mixed Alkylphosphites and Alkylphosphates

Some mixed phosphites having two different alkyl chain were obtained as forerunners for mixed phosphates Mixed dialkyl phosphates were obtained in good yields (40-80%) by phase transfer catalysis in liquid-liquid sistem, starting from different dialkyl phosphites and aliphatic alcohols. The reaction conditions were optimized in order to obtain good yields in phosphites and phosphates respectively. Compounds were analyzed by IR, P 31 -NMR.

Wittig and Wittig-Horner reactions under phase transfer catalysis conditions

Wittig and Wittig-Horner reactions are favorite tools in preparative organic chemistry. These olefination methods enjoy widespread and recognition because of their simplicity, convenience, and effciency. Phase transfer catalysis (PTC) is a very important method in synthetic organic chemistry having many advantages over conventional, homogenous reaction procedures. In this paper, we attempt to summarize the aspects concerning Wittig and Wittig-Horner reactions that take place under phase transfer catalysis conditions.

Phosphorus Compounds as Photoinitiators for Radicalic Polymerization

p-Methoxybenzoyldialkylphosphonates, where alkyl = methyl, ethyl andp-methoxy-benzoyldiphenylphosphine oxide were synthesized by Michaelis-Arbuzov reaction. These compounds were used as photoinitiators for radicalic polymerization of acrylic monomers. The photoreactivity parameters were determined by differential photocalorimetry(DPC), in isothermal conditions, using 1,6-hexandioldiacrylate(HDDA)as monomer, in the presence and absence of amine. The influence of concentration on film pendulum hardness was studied.

Chemical Modification of Functionalized Copolymers with Phosphonium Groups by Phase Transfer Catalysed Wittig Reactions

The interest for using polymers in Wittig reactions increased in the last years, because of their major advantages. Phase transfer catalyzed reactions are often more easily and cheaply carried out than conventional methods and they are therefore of particular interest. The phosphonium salts grafted on styrene-7%(5%)divinylbenzene copolymers used in this paper were obtained by quaternization polymer-analogous reaction. The degree of functionalization with quaternary phosphonium groups are relatively high, ranging from 1.84 to 1.98 mmoles/g of polymer. These grafted copolymers were used in liquid-liquid-solid Phase Transfer Catalysis(PTC)Wittig reaction. The yields were ranging from 1.84 to 1.98 mmoles of double bonds/gram of polymer.

Synthesis of Polyphosphates Related to Biopolymers

Polyphosphates were synthesized by base promoted liquid-vapor polycondensation of cyclohexylphosphoric dichloride with bisphenol A. The effects of temperature, reaction time, base concentration and molar ratio of reagents on yield, inherent viscosity and molecular weight of the obtained polymer were studied. A second order, central composite, rotatable experimental design was used to find domain experimental field for optimal yields and high inherent viscosities.

Synthesis of phosphorus derivatives from 1,3-dioxolan-2-one

A new route for the synthesis of some mixed organic phosphorus compounds from 1,3-dioxolan-2-one is reported. By heating a mixture of phosphorus-chlorine derivatives and 1,3-dioxolan-2-one in the presence of a catalyst, mixed phosphorus derivatives having 2-chloroethyl ester groups could be obtained. A wide range of phosphorus derivatives can be obtained using this method.

Synthesis of Phosphorus Containing Polymers by Phase Transfer Catalysis (PTC). II. Experimental Design for Polycondensation in Liquid-Vapor System

Abstract The simultaneous influence of four factors [reaction time (I), temperature (T), base concentration (c). molar ratio of the reagents (r)] on the yield (q) and on the inherent viscosity (qIv) of the product has been studied for the liquid-vapor system pol ycondensation of cyclohexyldichlorophosphonate (CDP) with bisphenol A (BA) by second order central composite circumscribed design. For a reasonable domain of the parameters [t = 30 ÷ 70 min., T = 20 ÷ 60 °C, c = 1 ÷ 5 mol/l, r = 1 ÷ 3.5 mol(CDP)/mol(BA)], designing the experiments, the η and ηiv values where determined in 31 synthesis (7 center points were used). In order to model the response (hyper)surfaces for η and ηiv, second order equations with interaction terms were used. Analyzing these model equations, T and c appear to be the most important factors, but acting in opposite way. Higher T resulted in greater yield and inherent viscosity. In the above defined domain the hypersurface of η presents a saddle point. From the sequential inspecti...

Synthesis of Some Mixed Dialkyl Phosphites and their Use as Forerunners for Potential Chiral Phosphates

Abstract Organophosphorus compounds containing a c h i d ccntrc at the P atom are of considerable interest fiom a stcreochemical point of view. Accordingly, trialkyl phosphates (RO)(RIO)(R20)P(0) (4) were synthesized starting from dialkyl phosphites. Thus: direct hydrolysis of dialkyl phosphites (ROhP(0)H (1) with tetraethylammonium hydroxide (20% aqueous solution), followed by extraction with dichloromethane affords the corresponding tetraethylammonium alkyl hydrogen phosphitcs (2). Good yields (q) of mixed dialkyl phosphites (3) were obtained on heating stoichiometric amounts of (2) and alkyl iodides in acetonitrile solution at 6O°C, for 6 hrs. Mixed dialkyl phosphites (3) were used in synthesis of some trialkyl phosphates (4) by PTC (see scheme).

The vapor-liquid polycondensation of cyclohexylphosphoric dichloride with hydroquinone

The vapor-liquid polycondensation of cyclohexylphosphoric dichloride with hydroquinone was investigated. The influence of the temperature, reaction time, base concentration, and molar ratio of reagents on the yield, inherent viscosity, and molecular weight of the obtained polymer was studied. Second order, central, composite, rotatable experimental design was used in order to carry out this work and to mark limits of the experimental field for optimal yields and high inherent viscosities.