Study of the phototransformation of imazaquin in aqueous solution: a kinetic approach

Barkani, H.; Catastini, Carole; Emmelin, Corinne; Sarakha, Mohamed; Azzouzi, Mohammed; Chovelon, Jean‐Marc

doi:10.1016/j.jphotochem.2004.07.017

Cited by 24 publications

(20 citation statements)

References 2 publications

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“…A fotólise é mais efetiva com pH maior ao pKa e na ausência de oxigênio. Em pH baixo, ocorre aumento de sorção e as moléculas tornam-se mais estáveis à fotodegradação (Barkani et al, 2005).…”

Section: Sorçãounclassified

“…As perdas de imazethapyr por hidrólise são mínimas a pH 5,0 ou 7,0, sendo praticamente nulas a pH 9,0 (t 1/2 H ≈ 9,6 meses a 25 o C) (Shaner & O'Connor, 1991). Foi demonstrado que a degradação hidrolítica não é importante para os herbicidas imazapyr (Curran et al, 1992;Quivet 2004Quivet , 2006a, imazethapyr (Curran et al, 1992), imazamox (Quivet, 2004(Quivet, , 2006a, imazamethabenz (Curran et al, 1992) e imazaquin (Curran et al, 1992;Barkani et al, 2005); não foram encontrados resultados de pesquisa sobre imazapic.…”

Section: Hidróliseunclassified

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Destino ambiental dos herbicidas do grupo das imidazolinonas: revisão

Kraemer¹,

Marchesan

Avila

et al. 2009

Planta daninha

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RESUMO -Os herbicidas do grupo das imidazolinonas controlam um amplo espectro de plantas daninhas, sendo absorvidos pelas raízes e folhas e translocados pelo floema e xilema, acumulando-se nos pontos de crescimento. Esse grupo de herbicidas atua inibindo a enzima acetolactato sintetase (ALS), essencial no processo de síntese de aminoácidos de cadeia ramificada em plantas. Quando aplicados nas lavouras, uma proporção significativa deles atinge o solo, onde são passíveis de serem absorvidos pelas raízes das plantas, sorvidos aos coloides do solo ou dissolvidos na sua solução, podendo sofrer fotólise, hidrólise, degradação microbiana ou lixiviação. A sorção das imidazolinonas é rápida e regula os outros processos. Altos conteúdos de argila e matéria orgânica e pH menor que 6,0 em solos aumentam a sorção e a persistência das imidazolinonas no solo. Condições que favoreçam o desenvolvimento de microrganismos aumentam a degradação das imidazolinonas, por ser essa a principal via de sua degradação.Palavras-chave: degradação, fotólise, hidrólise, mecanismo de ação, persistência, sorção.ABSTRACT -The herbicides of the imidazolinone group control a wide range of weed species. They are absorbed by weed roots and leaves and transported through the phloem and xylem, accumulating in the plant growing points. They inhibit the enzyme acetolactate synthase (ALS), which synthesizes the branched chain amino acids. When used in the field, a large portion of these herbicides reach the soil, where they can be absorbed by the roots of plants, sorbed into the soil colloids, or dissolved in soil solution, going through photolysis, hydrolysis, microbial degradation or leaching. The sorption of imidazolinone is faster and affects other processes. High contents of clay, organic matter and pH lower than 6.0 contribute to enhance the sorption and persistence of imidazolinones in soil. The most important way of dissipation is by microbial degradation, thus conditions favoring microbial development will also enhance imidazolinone degradation.

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Section: Sorçãounclassified

Section: Hidróliseunclassified

Destino ambiental dos herbicidas do grupo das imidazolinonas: revisão

Kraemer¹,

Marchesan

Avila

et al. 2009

Planta daninha

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“…In any case, both S* and T* are likely to be involved in the photolysis of these herbicides, based on LFP and quenching studies on imazethapyr. 48) …”

Section: Hetero Ringsmentioning

confidence: 99%

Direct photolysis mechanism of pesticides in water

Katagi

2018

Journal of Pesticide Science

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Photodegradation is one of the most important abiotic transformations for pesticides in the aquatic environment, and the high energy of sunlight causes characteristic reactions such as bond scission, cyclization, and rearrangement, which are scarcely observed in hydrolysis and microbial degradation. This review deals with direct photolysis via excitation of a pesticide by absorbing natural or artificial sunlight in order to know its basic photochemistry, and indirect photolysis meaning either sensitization by dissolved organic matters or oxidation by reactive oxygen species is basically excluded. Several experimental approaches including spectroscopic techniques together with theoretical calculations are first discussed from the viewpoint of the reaction mechanisms in direct photolysis. Then, the typical photoreactions of pesticides are summarized by chemical classes and/or functional groups and discussed as far as possible in relation to their mechanisms.

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“…At least four new reduction peaks appear in the differential pulse polarograms of the irradiated solutions. According to a previous work, 24 which studies the phototransformation of imazaquin in aqueous solution, four degradation products were identified by HPLC-UV and HPLC-MS. These products were proposed to be 2,3-pyridinecarboxylic acid, 7-hydroxyfuro[3,4-b]pyridine-5(7H)-one, 3-qinolinecarboxylic acid and a non-identified photoproduct.…”

Section: (A) and Absorbance Spectra (B) Ph=30 Adjusted With Hclmentioning

confidence: 99%

Electrochemical behavior of parent and photodegradation products of some selected pesticides

et al. 2008

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Recebido em 9/4/07; aceito em 15/2/08; publicado na web 31/7/08Electrochemical behavior of pesticides is extensively studied, but little attention has been given to the study of their degradation products (by-products) by electrochemical methods. However, the degradation products of pesticides can be even more toxic then the parent products and such studies should be encouraged. Therefore, the objective of this work was to evaluate the electroactivity of by-products of imazaquin, methylparathion, bentazon and atrazine, generated by UV irradiation and measured using cyclic and differential pulse voltammetry and UV-visible absorption spectrophotometry. Results have shown that several by-products exhibit electroactivity, allowing, in some cases, the simultaneous determination of both parent and degradation products.

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Study of the phototransformation of imazaquin in aqueous solution: a kinetic approach

Cited by 24 publications

References 2 publications

Destino ambiental dos herbicidas do grupo das imidazolinonas: revisão

Destino ambiental dos herbicidas do grupo das imidazolinonas: revisão

Direct photolysis mechanism of pesticides in water

Electrochemical behavior of parent and photodegradation products of some selected pesticides

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