• Blog Stats

    • 92,998 hits
  • Researchgate profile

  • Archives

  • Enter your email address to subscribe to this blog and receive notifications of new posts by email.

    Join 176 other followers

  • Follow Mark Foreman's Blog on WordPress.com
  • Copyright notice

    This blog entry and all other text on this blog is copyrighted, you are free to read it, discuss it with friends, co-workers and anyone else who will pay attention.

    If you want to cite this blog article or quote from it in a not for profit website or blog then please feel free to do so as long as you provide a link back to this blog article.

    If as a school teacher or university teacher you wish to use content from my blog for the education of students then you may do so as long as the teaching materials produced from my blogged writings are not distributed for profit to others. Also at University level I ask that you provide a link to my blog to the students.

    If you want to quote from this blog in an academic paper published in an academic journal then please contact me before you submit your paper to enable us to discuss the matter.

    If you wish to reuse my text in a way where you will be making a profit (however small) please contact me before you do so, and we can discuss the licensing of the content.

    If you want to contact me then please do so by e-mailing me at Chalmers University of Technology, I am quite easy to find there as I am the only person with the surname “foreman” working at Chalmers. An alternative method of contacting me is to leave a comment on a blog article. If you do not know which one to comment on then just pick one at random, please include your email in the comment so I can contact you.

  • Advertisements

Chlorothalonil

Dear Reader,

It has come to my attention that the EU will soon be banning a fungicide named chlorothalonil. This is a rather small molecule which has one benzene ring in it, two nitrile groups and four chlorine atoms. The molecular structure of this substance was reported by D. Britton (Cryst.Struct.Commun. , 1981, 10, 1501). Here is a picture of the molecule.

Chlorothalonil

Some of the chemistry and biology of this pesticide is discussed in a paper from the EFSA. This is a paper with a lot of authors.

Maria Arena, Domenica Auteri, Stefania Barmaz, Giulia Bellisai, Alba Brancato, Daniela Brocca, Laszlo Bura, Harry Byers, Arianna Chiusolo, Daniele Court Marques, Federica Crivellente, Chloe De Lentdecker, Mark Egsmose, Zoltan Erdos, Gabriella Fait, Lucien Ferreira, Marina Goumenou, Luna Greco, Alessio Ippolito, Frederique Istace, Samira Jarrah, Dimitra Kardassi, Renata Leuschner, Christopher Lythgo, Jose Oriol Magrans, Paula Medina, Ileana Miron, Tunde Molnar, Alexandre Nougadere, Laura Padovani, Juan Manuel Parra Morte, Ragnor Pedersen, Hermine Reich, Angela Sacchi, Miguel Santos, Rositsa Serafimova, Rachel Sharp, Alois Stanek, Franz Streissl, Juergen Sturma, Csaba Szentes, Jose Tarazona, Andrea Terron, Anne Theobald, Benedicte Vagenende, Alessia Verani and Laura Villamar-Bouza, EFSA Journal, 2018, 16(1), 5126.

While the impurity hexachlorobenzene which is found in the commercial product was characterized by .N.Strel’tsova and  Yu.T.Struchkov (Zh.Strukt.Khim.(Russ.)(J.Struct.Chem.) , 1961, 2, 312). This should not be confused with lindane which is sometimes known as hexachlorobenzene. Lindane is an isomer of 1,2,3,4,5,6-hexachlorocyclohexane. Here is a picture of hexachlorobenzene.

hexachlorobenzene

Like the pesticide it is a simple flat molecule which is a hexagon of carbon atoms within a hexagon of chlorine atoms.

The commercial product also contains small amounts of deachlorobiphenyl, as it is a PCB it is something which automatically grabbs my attention. This was characterized by B.F.Pedersen (Acta Crystallogr.,Sect.B:Struct.Crystallogr.Cryst.Chem., 1975, 31, 2931). This is a bit different, due to steric effects the two benzene rings are not in the same plane. Here are two views of it. First we have the side view.

side view of decachlorobiphenyl

Now here is the end view which is almost along the axis formed by the C-C single bond which links the two benzene rings together.

end view of decachlorobiphenyl

In the European food safety authority report, two metabolites (biological breakdown products) code named R613636 (2,3,4,6-tetrachloro-5-cyanobenzamide) and R182281 (2,4,5-trichloro-6-hydroxybenzene-1,3-dicarbonitrile) were listed as being of concern. We hope that we can discuss this molecule and chemistry soon.

Advertisements

Go on, Have your say !

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: