Fitotoksični efekti hlorpirifosa na ponike ječma i krastavca

Under Directive 2008/105 / EC, chlorpyrifos is one of the priority water pollutants. Its presence is mainly detected by chemical methods, although bioindicators are gaining in importance. The effect of chlorpyrifos (0.05-10 µg L-1) was evaluated on germination energy -GE and germination -G, length, fresh and dry weight of roots and shoots of barley and cucumber seedlings. In the bioassay, chlorpyrifos applied at MAC rate (0.1 µg L-1) caused a significant inhibition of GE and G of barley and at 0.5 µg L-1 of cucumber seeds, compared to control. At 50 % MAC (0.05 1 µg L-1), length, fresh and dry weight of roots and shoots of both tested plants were significantly inhibited, while in treatments with 0.5 µg L-1 and higher rates, there was no formation of hypocotyl and epicotyl of barley, i.e. hypocotyl of cucumber seedlings.Prema Direktivi 2008/105/EC, hlorpirifos je jedan od prioritetnih polutanata voda. Njegovo prisustvo se uglavnom detektuje hemijskim analizama, iako su sve značajnije i metode koje uključuju bioindikatore. U radu je procenjen uticaj hlorpirifosa (0,05-10 µg L-1) na energiju klijanja -EK, klijavost -K, dužinu, svežu i suvu masu korena i izdanka ječma i krastavca, kao potencijalnih indikatora. Hlorpirifos je izazvao značajnu inhibiciju EK i K semena ječma u MDK količini (0,1 µg L-1), a kod semena krastavca u količini 0,5 µg L-1, u odnosu na kontrolu. U količni 50% manje od MDK (0,05 µg L-1), dužina, sveža i suva masa i korena i nadzemnog dela obe test biljke su bili značajno smanjeni, dok u tretmanima sa preko 0,5 µg L-1 hlopririfosa, formiranje hipokotila i epikotila kod ječma, odnosno hipokotila kod krastavca, je izostalo

Ostaci pesticida u uzorcima povrća iz organske i konvencionalne proizvodnje

The detections of pesticides in organic and conventional productions were compared with the MRLs. Six vegetable samples from organic production, 4 from conventional production and one from the conversion period were analysed. The white potato sample from the organic production contained imidacloprid, propiconazole and piperonyl butoxide residues. Imidacloprid was found to be above the MRL. In the carrot sample from conventional production the azoxystrobin, boscalid, pyraclostrobin and difenoconazole were detected in the regulated limits, while the mandipropamid concentration were above the MRL.Poređene su detekcije pesticida sa propisanim MDK organskih i konvencionalnih proizvoda. Analizirano je šest uzoraka povrća iz organske, četiri iz konvencionalne proizvodnje i jedan iz perioda konverzije. Uzorak belog krompira iz organske proizvodnje sadržavao je ostatke imidakloprida, propikonazola i piperonil butoksid. Imidakloprid je bio iznad propisanih MDK. U uzoraku mrkve iz konvencionalne proizvodnje detektovani su azoksistrobin, boskalid, piraklostrobin i difenokonazol u propisanim granicama, dok je koncentracija mandipropamida bila iznad MDK

Synthesis of azo pyridone dyes

Over 50% of all colorants which are used nowdays are azo dyes and pigments, and among them arylazo pyridone dyes (and pigments) have became of interest in last several decades due to the high molar extinction coefficient, and the medium to high light and wet fastness properties. They find application generally as disperse dyes. The importance of disperse dyes increased in the 1970s and 1980s due to the use of polyester and nylon as the main synthetic fibers. Also, disperse dyes were used rapidly since 1970 in inks for the heat-transfer printing of polyester. The main synthetic route for the preparation of azo dyes is coupling reaction between an aromatic diazo compound and a coupling component. Of all dyes manufactured, about 60% are produced by this reaction. Arylazo pyridone dyes can be prepared from pyridone moiety as a coupling component, where substituent can be on nitrogen, and diazonim salts which can be derived from different substituted anilines or other heterocyclic derivatives. In addition, arylazo dyes containing pyridone ring can be prepared from arylazo diketones or arylazo ketoesters (obtained by coupling β-diketones or β-ketoesters with diazonim salts) by condensation with cyanoacetamide. Disazo dyes can be prepared by tetrazotizing a dianiline and coupling it with a pyridone or by diazotizing aniline and coupling it with a dipyridone. Trisazo dyes can be also prepared by diazotizing of aniline and coupling it with a tripyridone or by hexazotizing a trianiline and coupling it with a pyridone. The main goal of this paper is to give a brief review on the synthesis of arylazo pyridone dyes due to the lack of such reviews. In addition, some properties of arylazo pyridone dyes as light fastness and azo-hydrazon tautomerism are disccused

Azo-hydrazone tautomerism of aryl azo pyridone dyes

In the last three or four decades disperse dyes derived from pyridones (in particular azo pyridone dyes) have gained in importance, and are widely used in various fields. These compounds have excellent coloration properties, and are suitable for the dyeing of polyester fabrics. Basic features of these dyes are simplicity of their synthesis by diazotation and azo coupling. They generally have high molar extinction coefficient with medium to high light and wet fastness. The absorption maxima of these dyes show their visible absorption wavelength ranging from yellow to orange, which can be attributed to poorly delocalized electrons in the pyridone ring. However, there are several dyes with deep colors such as red or violet. Pyridone dyes with alkyl and aryl groups in ortho position to azo group show 2-pyridone/2-hydroxypyridine tautomerism, while those containing OH and NHR groups conjugated with the azo group show azo-hydrazone tautomerism. Determining azo-hydrazone tautomerism could be therefore interesting, since the tautomers have different physico-chemical properties and most importantly different coloration. The literature on azo-hydrazone tautomerism, determination of equilibrium position, and investigation of substituent and solvent influence on tautomerism has been summarized in the presented review. The general conclusion is that the equilibrium between two tautomers is influenced by the structure of the compounds and by the solvents used. The tautomeric behavior patterns of the arylazo pyridone dyes in the reviewed literature has been studied using various instrumental techniques, including FT-IR, UV-vis, and NMR spectroscopy. The quantum chemical calculations related to the azo-hydrazon tautomerism have also been included. A large number of pyridone dyes exist in hydrazone form in solid state, while in solvents there is a mixture of tautomers. In addition, the X-ray single-crystal diffraction data analysis of some commercial pyridone dyes has been discussed concluding that they all crystallize in the hydrazone form.Arilazo piridonske boje su obojene supstance koje zbog svojih specifičnih svojstava kao i primene u različitim industrijskim oblastima predstavljaju značajan predmet istraživanja u poslednjih nekoliko decenija. Osnovna svojstva ovih boja su visoki ekstinkcioni koeficijenti kao i dobra postojanost na mokre obrade. Arilazo piridonske boje su pogodne za bojenje sintetskih vlakana i daju nijanse izmeću žute i narandžaste. Zbog uticaja strukture na obojenost, azo-hidrazon tautomerija je tema velikog broja radova. U ovom radu sumirana su dosadašnja istraživanja koja se odnose na azo-hidrazon tautomeriju arilazo pridonskih boja, kao i na mogućnost odrećivanja odnosa tautomera korišćenjem različitih spektroskopskih metoda. Osim toga, razmatrana su i istraživanja koja se bave ispitivanjem kristalne strukture tautomera koji se koriste kao komercijalne boje

Correlation analysis of IR, 1H and 13C NMR spectral data of N-alkyl and N-cycloalkyl cyanoacetamides

Linear free energy relationships (LFER) were applied to the IR, 1H- and 13C- -NMR spectral data in N-alkyl and N-cycloalkyl cyanoacetamides. N-alkyl and N-cycloalkyl cyanocetamides were synthesized from corresponding amine and ethyl cyanoacetate. A number of substituents were employed for alkyl substitution, and fairly good correlations were obtained, using simple Hammett equation. In N-alkyl and N-cycloalkyl cyanoacetamides substituent cause SCS of N-H hydrogen primarily by steric interaction, polar subtituent effect influences SCS shift of C=O carbon, while steric effect of N-alkyl substituent causes IR stretching frequencies of N-H, C=O and CN group. The conformations of investigated compounds have been studied by the use of semiempirical PM6 method, and together with LFER analysis, give a better insight into the influence of such a structure on the transmission of electronic substituent effects. Negative ρ values for several correlations (reverse substituent effect) were found.Principi linearnih korelacija slobodnih energija (LFER) su primenjeni na IR, 1H- i 13C-NMR spektralne podatke N-alkil i N-cikloalkilcijanoacetamida. Širok opseg alkil i cikloalkil suptituenata je korišćen pri sintezi N-alkil i N-cikloalkilcijanoacetamida sa ciljem ispitivanja uticaja njihovih elektronskih i sternih efekata na IR, 1H i 13C NMR spektralne podatke. Zadovoljavajuće korelacije su dobijene primenom proste Hammett-ove jednačine. Na osnovu korelacionih rezultata uočen je primaran uticaj sternih efekata supstituenata na SCS (supstituent indukovana hemijska pomeranja) vrednosti N-H vodonika ispitivanih jedinjenja, što je posledica blizine i različitih konformacija N-alkil i N-cikloalkil supstituenata. Takođe se uočava reversni efekat supstituenata na SCS pomeranja karbonilnog C=O ugljenika, kao posledica π-polarizacije. Indukovani dipol na N-alkil ili N-cikloalkil supstituentu izaziva povećanje elektronske gustine karbonilnog ugljenika iako elektron-akceptorski efekat supstituenta raste. Može se zaključiti da se efekat π-polarizacije odražava na veličinu rezonancionog efekta amidne grupe. Polarni efekat N-alkil ili N-cikloalkil supstituenata se primarno prenosi efektom polja kroz prostor. Uticaj efekata N-alkil ili N-cikloalkil supstituenata na IR vibracije istezanja N-H (simetrične i antisimetrične), C=O i CN veze je prevashodno određen konformacionim (sternim) efektom supstituenata koji utiče na jačinu veze, a time i na položaj trake u odgovarajućem spektru

EI/MS/MS spectra of N-monosubstituted cyanoacetamides

Capital account liberalization in financially repressed economies often leads to a period of rapid capital inflows followed by financial crisis. This paper considers the vulnerability of the Indian economy to financial crises with international financial integration and the policy agenda for further liberalization of capital flows. The legacy of financial repression on fiscal and financial policies poses the primary challenge to stable integration of the domestic financial markets of India with international capital markets. Brief overviews of the theory and experience of liberalization elsewhere and of the recent liberalization by India frame the discussion of the risks of liberalization and sequencing of policy reforms

Thermal and dielectric properties of low-density polyethylene/NaA zeolite composites

The effect of the weight fraction of NaA zeolite on thermal properties (specific heat capacity, thermal diffusivity, thermal conductivity) and dielectric properties (electrical conductivity, real and imaginary electric permittivity) of composites based on low-density polyethylene (LDPE) and NaA zeolite is examined. Composite samples containing from 5 to 30 wt% zeolite are prepared using the compression molding technique. The degree of dispersion and the weight fraction of filler in the LDPE/NaA zeolite composites are determined using X-ray diffraction. A linear decrease in the values of the specific heat capacity with an increase in the weight fraction of zeolite is observed using differential scanning calorimetry. The laser flash method is used to determine the thermal diffusivity of the composites. An increase in effective thermal diffusivity and abrupt increase in the range from 15 to 20 wt% of zeolite are established. It is demonstrated that effective thermal conductivity increases with an increase in the weight fraction of zeolite, and an abrupt increase in the range from 15 to 20 wt% is observed. Dielectric spectroscopy measurements are performed to determine the real and imaginary parts of permittivity. An increase of real and imaginary parts of permittivity of LDPE/NaA zeolite composites, with increasing weight fraction of zeolite, is established. Two relaxation peaks of the imaginary parts of permittivity of LDPE/NaA zeolite composites are detected. An increase of electrical conductivity with increasing weight fraction of zeolite and abrupt increase in the range 15 to 20 wt% are noticed. (c) 2021 Society of Industrial Chemistry