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Chloroacetic Acid (chloroacetic + acid)
Selected AbstractsSynthesis of charged ultrafiltration poly(styrene- co -divinyl benzene) composite membraneJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Sonny Sachdeva Abstract A ceramic supported crosslinked polystyrene composite membrane has been prepared from its monomers using a dual initiator system. The nonionic hydrophobic membrane so prepared has been chemically modified by a low temperature (50°C), single step reaction with chloroacetic acid. The carboxylated membrane has acid functional groups on its surface making it negatively charged and highly hydrophilic in nature. The membranes (unmodified and carboxylated) have been used for the separation of hazardous chromium (VI) salt solution where observed and intrinsic rejection has been studied as a function of pressure and concentration of the feed solution. The intrinsic rejection has been determined by calculating the concentration at the membrane surface (Cm) using Speigler-Kedam model and osmotic pressure model. The observed rejection for the chemically modified membrane decreases with increasing pressure but the intrinsic rejection is found to be more than 80% for all concentrations in the range of study. The experimental results have been fitted using Space-Charge model to obtain the membrane wall potential and the membrane surface concentration which are difficult to measure directly. The transport through the membrane capillaries has been described by the two dimensional model using Nernst-Planck equation for ion transport, Navier-Stokes equation and Poisson-Boltzmann equation for the radial distribution of potential. We have then presented a semianalytical series solution to the highly nonlinear Poisson-Boltzmann equation to reduce the computational time required to solve the set of coupled differential equations. The effective wall potential of the carboxylated membrane was found to be ,28.07 mV. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis, characterization and studies of new 3-benzyl-4H -1,2,4-triazole-5-thiol and thiazolo[3,2- b][1,2,4]triazole-5(6H)-one heterocyclesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 3 2008Abdelwareth A. O. Sarhan 3-Benzyl-4-phenyl-1,2,4-triazole-5-thiol (1) was synthesized and used as starting material for preparation of 1,2,4-triazole bearing substituted thiosemicarbazides moiety (4a-d) in high yields. The thiosemicarbazides 4a-d were cyclized in basic medium to give two triazole rings linked by thiomethylene group (5a-d), while cyclization of thiosemicarbazides 4a-d with chloroacetyl chloride in the presence of CHCl3 and K2CO3 afforded the thiazolidinone derivatives 6a-d. The reaction of thiosemicarbazides 4a-c with phenacyl bromide in the presence of EtOH and fused CH3COONa gave the corresponding thiazoline ring systems 7a-c. Condensation of the 3-benzyl-1,2,4-triazole-5(1H)-thiol (1) with chloroacetic acid and aromatic aldehydes (8a- g) in boiling acetic acid/acetic anhydride mixture in the presence of fused sodium acetate gave one single isomer only, which might be 9a-g or 10a-g. Upon application of Micheal addition reaction on compounds 9a-e with cyclic secondary amines such as piperidine or morpholine the 2-benzyl-6-(,-amino-aryl/methyl)-1,3-thiazolo[3,2- b][1,2,4]-triazol-5-ols (11a-j) were obtained in good yields The structure of all new compounds were determined using both spectral and elemental analyses. [source] Synthesis of some thiazolyl and thiadiazolyl derivatives of substituted furan and pyrroleJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 1 2007Seham Y. Hassan Four series of substituted furan and pyrrole have been synthesized. The first series was prepared by cyclization of the key intermediates ethyl 5-[(4-substituted thiosemicarbazido)methyl]-2-methylfuran-3-carboxylates 2a-2d and 1-[(4-acetyl-5-methyl-1H -pyrrol-2-yl)methylene]-4-substituted thiosemicarbazides 8a-8d with chloroacetic acid or (ethyl bromoacetate) to afford the corresponding 4-oxo-3-substituted thiazolidin-2-ylidene 3a-3d or 3-substituted thiazolidin-4-one 9a-9d. On the other hand, heating of the intermediates 2a-2d or 8a-8d with acetic anhydride afforded the corresponding (N -substituted acetylamino)-2,3-dihydro-[1,3,4]thiadiazol-2-yl derivatives 4a-4d and [1,3,4]thiadiazol-2-yl- N -substituted acetamide 10a-10d respectively, while cyclization with p -bromophenacyl bromide gave rise to the corresponding 3-substituted thiazol-2-yl-ylidene 5a-5d and 11a-11d respectively. Furthermore, 4-oxo-3-substituted thioureido-thiazolidin-2-yl 6a-6d or 4-oxo-thiazolidin-3-yl-3-substituted thiourea 12a-12d were obtained by reaction of the intermediates 2a-2d or 8a-8d with thioglycolic acid. Some of the synthesized compounds showed promising antimicrobial activities. [source] Synthesis and reactions of 3-amino-2-methyl-3H -[1,2,4]triazolo[5,1- b]-quinazolin-9-one and 2-hydrazino-3-phenylamino-3H -quinazolin-4-oneJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2003Mohamed A. Saleh The reaction of 3- N -(2-mercapto-4-oxo-4H -quinazolin-3-yl)acetamide (1) with hydrazine hydrate yielded 3-amino-2-methyl-3H -[1,2,4]triazolo[5,1- b]quinazolin-9-one (2). The reaction of 2 with o -chlorobenzaldehyde and 2-hydroxy-naphthaldehyde gave the corresponding 3-arylidene amino derivatives 3 and 4, respectively. Condensation of 2 with 1-nitroso-2-naphthol afforded the corresponding 3-(2-hydroxy-naphthalen-1-yl-diazenyl)-2-methyl-3H -[1,2,4]triazolo[5,1- b]quinazolin-9-one (5), which on subsequent reduction by SnCl2 and HCl gave the hydrazino derivative 6. Reaction of 2 with phenyl isothiocyanate in refluxing ethanol yielded thiourea derivative 7. Ring closure of 7 subsequently cyclized on refluxing with phencyl bromide, oxalyl dichloride and chloroacetic acid afforded the corresponding thiazolidine derivatives 8, 9 and 10, respectively. Reaction of 2-mercapto-3-phenylamino-3H -quinazolin-4-one (11) with hydrazine hydrate afforded 2-hydrazino-3-phenylamino-3H -quinazolin-4-one (12). The reactivity 12 towards carbon disulphide, acetyl acetone and ethyl acetoacetate gave 13, 14 and 15, respectively. Condensation of 12 with isatin afforded 2-[N -(2-oxo-1,2-dihydroindol-3-ylidene)hydrazino]-3-phenylamino-3H -quinazolin-4-one (16). 2-(4-Oxo-3-phenylamino-3,4-dihydroquinazolin-2-ylamino)isoindole-1,3-dione (17) was synthesized by the reaction of 12 with phthalic anhydride. All isolated products were confirmed by their ir, 1H nmr, 13C nmr and mass spectra. [source] On-line solid-phase extraction with a monolithic weak cation-exchange column and simultaneous screening of ,1-adrenergic receptor antagonists in human plasmaJOURNAL OF SEPARATION SCIENCE, JSS, Issue 17 2007Xiaoyi Wei Abstract An on-line SPE,HPLC method, using a monolithic poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) (poly(GMA-EDMA)) based weak cation-exchange (WCX) column, was developed for simultaneous determination of ,1-adrenergic receptor antagonists in human plasma. The monolithic WCX column was prepared by an in-situ polymerization protocol and modified stepwise with ethylenediamine and chloroacetic acid. On connecting this column to an injection valve, an on-line SPE protocol could be established for removal of matrices (mainly proteins and lipids) and preconcentration of four ,1-adrenergic receptor antagonists in human plasma. This method was validated and then used for determination of terazosin, alfuzosin, prazosin, and doxazosin in clinical plasma samples. For all analytes, each calibration curve was found to be linear over a range of 0.005,5 ,g/mL (R >0.997), and the limit of detection for each analyte was 0.5 ng/mL. Recovery (> 80%) and precision (RSD <15%) for inter- and intra-day assay were tested at three concentration levels of each analyte and showed acceptable results for quantitative assay. Real samples from hypertensive patients were monitored and results were in agreement with those of the conventional liquid,liquid extraction-HPLC method. Furthermore, due to its good permeability and biocompatibility, the monolithic WCX sorbent could be reused more than 300 times. The proposed method was especially appropriate for multi-analyte monitoring in plasma samples. [source] BIODEGRADATION OF DISINFECTION BYPRODUCTS AS A POTENTIAL REMOVAL PROCESS DURING AQUIFER STORAGE RECOVERY,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 4 2000James E. Landmeyer ABSTRACT: The biodegradation potential of two drinking water disinfection byproducts was investigated using aquifer materials obtained from approximately 100 and 200 meters below land surface in an aerobic aquifer system undergoing aquifer storage recovery of treated surface water. No significant biodegradation of a model trihalomethane compound, chloroform, was observed in aquifer microcosms under aerobic or anaerobic conditions. In contrast, between 16 and 27 percent mineralization of a radiolabeled model haloacetic acid compound, chloroacetic acid, was observed. These results indicate that although the potential for biodegradation of chloroacetic acid exists in deep aquifer systems, chloroform entrained within these aquifers or formed in situ will tend to persist. These results have important implications for water managers planning to meet anticipated lowered permissible levels of trihalomethanes in drinking water. [source] | ||||||||||