Chemistry of 2,4-Dioxothiazolidine. II. Ammonolysis of 2,4 Dioxothiazolidine and its Derivatives

It is found that the ammonolysis of 2,4-dioxothiazolidine gives 5-amino-2,3-dithiacaprohydroxamic·· add, while 3-plienyl-2,4-dioxothiazolidine is transformed in glycolic acid N-(2-amino-1-hydroxyethyl)- anilide. The product of ammonolysis of 3-(3-4-dichlorophenyl)- 2,4-dioxothiazolidine proved to be 3,4-dichlorophenylcarbamid

GC/MS and TOC Analyses of Ibuprofen after Degradation in Waterusing Chlorine Dioxide

Drinking water and wastewater treatment facilities often have a chemical oxidationstep for disinfection, the removal of organic micropollutants, color removal and taste andodor control. Among the most commonly used oxidants are chlorine dioxide (ClO2 ), chlorine, and ozone.ClO2 has been increasinglyemployed as disinfectant in water treatment due to its antibacterial and antiviral properties. As a powerful oxidant, ClO2 can remove many organic and inorganic pollutants [1,2]. The aim of the present study was to assess thepotential of ClO2 to oxidize pharmaceutical during water treatment. Therefore, degradation of ibuprofen (IBP) using ClO2 in water was investigated.The degradation under different reaction conditions (concentration of ClO2 : 5, 10, 15 mg/L; concentration of ibuprofen: 10, 20, 35, 60 mg/L; reaction time: from 0.5 to 24 h; pH values: 3, 7, 10) was monitored using high performance liquid chromatography (HPLC) analysis, while mineralization degree was detemined by total organic carbon (TOC) measurements. The highest degree of IBPdegradation in deionized water was obtained by treatment with 15 mg/L ClO2 , using 10 mg/L ibuprofen, at pH = 10, after 24 h of treatment. The obtained degradation degree value under optimal conditions was 99%. TOC analysis of ibuprofen showed reduction in content of organic carbon in the solution. Before degradation TOC content was 7.8 mg/L and after 5.6 mg/L. This showes that degradation and mineralization of ibuprofen occur during this process. The degradation products obtained under optimal conditions were analyzed and confirmed by gas chromatography–mass spectra (GC–MS) and the reaction pathwayswere proposed.From GC chromatograms, degradation products of ibuprofen appeared at following retention times: 4.35 min, 5.12 min, 6.76 min, and 7.05 min. After the analysis of mass spectra, based on the spectral characteristics and the ratio of mass and charge (m/z), it was determined that there are four main degradation products of ibuprofen, after treatment with ClO2.The first characteristic ion appeared at 6.76 min and has m/z 163 (2-(4-methylphenyl) propionic acid). In further degradation path, two products are formed, one of which is a characteristic ion with m/z 57 (2-methylpropane) at 4.36 min, while the other product is further decomposed to give two new products, one of which is also a characteristic ion with m/z 57 (acetic acid) at 5.21 min. Another characteristic ion having m/z 161 (1-ethyl-4-isobutylbenzene) appeared at 7.05 min. ClO2 treatment is an efficient method for IBP degradation.The findings of the present study are very useful for the treatment of drinking waters contaminated with pharmaceutical

Characterization of polyurethane crosslinked structures based on hyperbranched polyester

The novel polyurethane crosslinked structures based on α,ω-dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide) (EO-PDMS-EO), 4,4’- methylenediphenyl diisocyanate and Boltorn® hyperbranched polyester of the second pseudo generation were characterized by infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis. The chemical structure and hydrogen-bond interactions of these polymers were investigated by infrared spectroscopy. The carbonyl region was fitted by the Gaussian deconvolution technique, using the PeakFit program, resulting in the determination of locations and areas of each band. The polyurethanes exhibited five absorbance peaks in carbonyl region: hydrogen-bonded carbonyl groups in ordered hard domains at 1690 cm-1, free (non-bonded) carbonyl groups at 1735 cm-1, hydrogen-bonded carbonyl groups in disordered domains at 1715 cm-1, free carbonyl groups from ester bonds at 1725 cm-1 and hydrogen-bonded carbonyl groups from ester bonds at 1650 cm-1. The deconvolution procedure showed very good agreement between observed and generated values. The fit standard error was in the range from 0.00013 to 0.0028 and r2 > 0.994. The hydrogen bonds formation between urethane groups and between urethane –NH and ester carbonyl groups in polyurethanes increases with the decrease of EO-PDMS-EO content. The EDX analyses, performed to indentify the nature of the atoms present in the samples at a depth of 100-1000 nm from the surfaces, revealed the presence of all expected elements (C, O, Si and N). The Si percentage detected by EDX on the surface of polyurethanes increases with increasing PDMS content. The surface morphology of the polyurethanes indicated that the separation of the micro-domains was improved by increasing EO-PDMS-EO content. Thermal stability of polyurethanes increased with increase of EO-PDMS-EO content up to the temperature corresponding to the approximately 50 % of weight loss. However, at higher temperatures thermal degradation became slower for samples with lower EO-PDMS-EO content

Optimizacija uslova za degradaciju pesticida pomocu hlor dioksida

The аim of this study was to find optimal conditions for degradation of pesticides, such as pethoxamid and metazachlor with chlorine dioxide in deionized water.Cilj ovog rada је bio da se pronadju optimalni uslovi za degradaciju pesticida, kao sto su: petoksamid i metazahlor роmоću hlor dioksida u dejonizovanoj vodi

Degradation of triazine group herbicides by chlorine dioxide

This study investigates degradation of triazine group herbicides (atrazine, terbuthylazine and prometryn) with chlorine dioxide in deionized water and in real water system (water from river Sava) under optimal conditions

Supplementary material for the article: Pergal, M. V.; Kodranov, I. D.; Pergal, M. M.; Dojčinović, B. P.; Stanković, D. M.; Petković, B. B.; Manojlović, D. D. Assessment of Degradation of Sulfonylurea Herbicides in Water by Chlorine Dioxide. Water, Air, and Soil Pollution 2018, 229 (9). https://doi.org/10.1007/s11270-018-3947-2

Supplementary material for: [https://doi.org/10.1007/s11270-018-3947-2]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2203

Degradation herbicides with chlorine dioxide: degradation efficiency and toxicity test

The main objective of this study was to find optimal parameters for degradation of herbicides, such as nicosulfuron and thifensulfuron-methyl, with chlorine dioxide in deionized water. In order to examine the optimal parameters, degradation of herbicides was investigated under light or dark conditions with different amount of chlorine dioxide (5 and 10 ppm), different time of degradation (30 min, 1, 2, 3, 6 and 24 h) and at different pH values (3, 7 and 9). Degradation efficiency of herbicides was monitored using HPLC-DAD. Acute toxicity tests were performed for degradation products after the treatment with chlorine dioxide

Poli(uretan-siloksani) na bazi hiperrazgranatog poliestra kao umreživača - sinteza i karakterizacija

A series of novel polyurethane crosslinked structures (PUs) was prepared from α,ω-dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide) (EO-PDMS-EO), 4,4'-methylenediphenyl diisocyanate and Boltorn ® hyperbranched polyester of the third pseudo generation. The hydroxyfunctional hyperbranched aliphatic polyester with 26 end groups was used as a crosslinking agent. In order to improve the compatibility of all the reactants during the synthesis, the PU samples were prepared by two-stage, step-growth polymerization in solution. The content of the soft EO-PDMS-EO segments was varied in the range from 15 to 40 wt. %. The influence of the EO-PDMS-EO content on the swelling behavior, crosslink density, hardness, and the thermal and surface properties of the synthesized PUs was investigated. The structure of the synthesized polyurethanes was confirmed by the presence of specific bands in the Fourier transform infrared spectra. Swelling studies were performed to determine the crosslink density and polyurethane networks with lower EO-PDMS-EO contents had higher crosslink densities. The glass transition temperature of the synthesized PUs, determined by differential scanning calorimetry, slightly increased from 50 to 58°C on decreasing the EO-PDMS-EO content because of the higher crosslink density of the samples. Increasing the EO-PDMS-EO content led to better thermal stability, as was evidenced by the onset temperature of weight loss. The surface of the polyurethane networks became more hydrophobic with increasing EO-PDMS-EO content. The surface morphology of synthesized polyurethanes was analyzed by scanning electron microscopy.U ovom radu prikazana je sinteza, struktura i neka svojstva novih umreženih poliuretana pripremljenih polazeći od α,ω-dihidroksi-(etilenoksid-poli(dimetilsiloksan)-etilenoksid) pretpolimera (EO-PDMS-EO), 4,4'-metilendifenildiizocijanata i Boltorn® hiperrazgranatog poliestra treće pseudo-generacije. Hiperrazgranati hidroksi funkcionalni alifatski poliestar sa 26 krajnjih grupa služio je kao umrežavajući agens pri sintezi poliuretana. U cilju poboljšanja kompatibilnosti reaktanata tokom sinteze, poliuretani su sintetisani dvostepenom polimerizacijom u rastvoru. Sadržaj mekog EO-PDMS-EO segmenta variran je u opsegu od 15 do 40 mas. %. Ispitan je uticaj EO-PDMS-EO sadržaja na ponašanje pri bubrenju, gustinu umrežavanja, tvrdoću, termička i površinska svojstva sintetisanih poliuretana. Struktura sintetisanih poliuretana potvrđena je FTIR spektroskopijom. Ponašanje pri bubrenju je ispitivano kako bi se odredila gustina umrežavanja i pokazano je da poliuretanske mreže sa nižim EO-PDMS-EO sadržajem imaju veću gustinu umrežavanja. Rezultati diferencijalne skenirajuće kalorimetrije pokazali su povećanje temperature ostakljivanja poliuretana od 50 do 58°C sa smanjenjem EO-PDMS-EO sadržaja kao posledicu veće gustine umreženosti uzoraka. Sintetisani poliuretani sa većim sadržajem EO-PDMS-EO segmenata pokazuju bolju termičku stabilnost, što je potvrđeno porastom početne temperature degradacije, određene TG analizom. Hidrofobnost površine poliuretana je rasla sa povećanjem sadržaja EO-PDMS-EO u odgovarajućem uzorku. Površinska morfologija sintetisanih poliuretana je analizirana skenirajućom elektronskom mikroskopijom

Surface and thermomechanical characterization of polyurethane networks based on poly(dimethylsiloxane) and hyperbranched polyester

Two series of polyurethane (PU) networks based on Boltorn® hyperbranched polyester (HBP) and hydroxyethoxy propyl terminated poly(dimethylsiloxane) (EO-PDMS) or hydroxy propyl terminated poly(dimethylsiloxane) (HPPDMS), were synthesized. The effect of the type of soft PDMS segment on the properties of PUs was investigated by Fourier transform infrared spectroscopy (FTIR), contact angle measurements, surface free energy determination, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC). The surface characterization of PUs showed existence of slightly amphiphilic character and it revealed that PUs based on HP-PDMS have lower surface free energy, more hydrophobic surface and better waterproof performances than PUs based on EO-PDMS. PUs based on HPPDMS had higher crosslinking density than PUs based on EO-PDMS. DSC and DMTA results revealed that these newlysynthesized PUs exhibit the glass transition temperatures of the soft and hard segments. DMTA, SEM and AFM results confirmed existence of microphase separated morphology. The results obtained in this work indicate that PU networks based on HBP and PDMS have improved surface and thermomechanical properties

Proučavanje morfologije i termomehaničkih svojstava umreženih poli(uretan-siloksana) na bazi hiperrazgranatog poliestra

Two series of polyurethane films based on hyperbranched polyester of the second pseudo-generation (Boltorn®), 4,4'-methylenediphenyl diisocyanate and two different siloxane prepolymers, α,ω-dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide)(EO-PDMS-EO) and α,ω-dihydroxypropyl-poly(dimethylsiloxane) (HP-PDMS), were prepared by two-step polymerization in solution. The influence of the type and content of soft segment on the morphology, thermomechanical and surface properties of the synthesized polyurethanes was studied by atomic force microscopy (AFM), small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA) and water absorption measurements. It was found that these techniques confirmed existence of microphase separated morphology. Synthesized polyurethanes exhibited two glass transition temperatures and one second relaxation process. The results showed that polyurethanes based on HP-PDMS had higher surface roughness, better microphase separation and waterproof performances. Samples synthesized with lower PDMS content had less hydrophobic surface, but higher crosslinking density and better thermomechanical properties.U ovom radu pripremane su dve serije poliuretanskih filmova na bazi hiperrazgranatog poliestra druge pseudo generacije (Boltron), 4,4¢-metilendifenildiizocijanata i dva različita iloksanska pretpolimera kao što su a, ω-dihidroksi- (etilenoksid-poli(dimetilsiloksan)-etilenoksid)(EO-PDMS-EO) i a,ω-dihidroksipro-pilpoli(dimetilsiloksan)(HP-PDMS), dvostepenom polimerizacijom u rastvoru. Uticaj vrste i sadržaja mekog segmenta na morfologiju, termomehanička i površinska svojstva sintetisanih poliuretana je proučavan pomoću mikroskopije atomske sila (AFM), rasipanja X-zraka pod malim uglovima (SAXS), skenirajuće elektronske mikroskopije (SEM), dinamičko mehaničke termičke analize (DMTA) i merenja količine apsorbovane vode. Nađeno je da primenjene tehnike potvrđuju postojanje morfologije mikrofaznog razdvajanja. Sintetisani poliuretani pokazivali su dve temperature ostakljivanja i jedan sekundarni relaksacioni proces. Rezultati su pokazali da poliuretani na bazi HP-PDMS su imali veći koeficijent hrapavosti, bolje mikrofazno razdvajanje i bolju otpornost prema vodi. Uzorci sintetisani sa nižim sadržajem PDMS-a su imali manju hidrofobnost, ali veću gustinu umrežavanja i bolja termomehanička svojstva