Agrochemicals

Agrochemicals, RrSOaNHa + ClSOa NCO — RsSOa NCO (Rp = Ci—Cs perfluoroalkyl). CFs SOa NH-Substituted aromatics. (CFj-sjst-Tfti + CFg - 

CR1R2 Ri = H or F R = H, F, or Cl) adducts. RpS-N-Substituted compounds (Rf = chlorofluoroalkyl). CF2C1-S-Substituted aromatics.  

Plant protection is more necessary today than ever before. It is of prime importance for the safeguarding of our food supply Whereas over the last 50 years the usable agricultural area has remained more or less constant (1.4 billion hectares worldwide) [ 1 ], the human population has grown during the same period from 2.5 to more than 7 billion, which translates statistically into only around 0.2 hectares ( 0.5 acres) per capita nowadays (Fig. 8.1). 

1 A plot roughly the size of a quarter of a football field must grow all the necessities of life for each of us. 

Since the Neolithic Age, around 10,000 years ago, Man has cultivated the land. The crops, as we know them today, were bred from wild plant species. A sophisticated irrigation technique in Mesopotamia and Egypt allowed more people to be fed. Hence, the first advanced civilisations emerged, especially in North Africa and the Middle East, some 6000 years ago. As we learned from Sumerian texts and from Egyptian decriptions, locusts, beetles, rodents and fungal diseases threatened the harvests already in those days (Fig. 8.2). [2] 

Also Chinese documents from the Shang Dynasty (1523-1027 BC) reveal the threats posed by insects. Therefore, attempts were made to battle, for example, the migratory locust Locusta migratoria maniiensis with fire. In Greek and Roman writings, there are reports of plant damage, preventive measures, and pest control possibilities. For instance, Phny the Elder describes the use of ashes, crushed cypress leaves and diluted urine as insect repellents. 

Q/n theyears 1845-1850, a fungal infection of potatoes (Solanum tuberosum L) with Phytophtora infestans was rife in Ireland this led to a starvation, known as the Great Irish Famine , as a result of which, more than a million people died and two million emigrated. 

One of the simplest pyridazine derivatives, maleic hydrazide, is a long established herbicide which is still widely used, among other purposes, to retard the growth of established plants such as hedges 

Irradiation of the herbicide propanil gives rise to complex mixtures containing the products arising from PFR of the anilide moiety [184]. In the carbamate series, isoprocarb and promecarb give rise to the ortho- andpara-hydroxybenzamides, whereas bendiocarb, thiobencarb, furathiocarb, fenoxy-carb, and pirimicarb lead mainly to the corresponding phenols [185]. 

Combined photosensitization and quenching experiments suggest the involvement of both singlet and triplet excited states. The latter is indeed observed in laser flash photolysis [189]. 

The agrochemical industry developed to assist in providing more food by 

Division of agrochemicals into two sections, artificial fertilizers and pesticides, is justified for several other reasons. One of these is the scale on which the chemicals are produced. Fertilizer production is a good example of very large-scale chemical production. Much of it revolves around the manufacture of ammonia—these plants are the giants of the chemical industry, with a single plant easily capable of producing 1000 tonnes per day (see Table 5.1, and also section 9.4.1.2 of Volume I). 

Production of individual pesticides rarely exceeds 1 000 tonnes per year, and is typically hundreds of tonnes. 

A second contrast is the nature of the compounds. Those used as fertilizers consist largely of small number of simple inorganic compounds such as ammonium salts, nitrates and phosphates. Modern pesticides are virtually all organic compounds and the range of chemical structures which they cover is very diverse, encompassing practically all areas of organic chemistry. 

Thirdly, the compounds used as fertilizers and their manufacturing processes are now well established, i.e. mature. Therefore the little research that is undertaken is directed mainly at improving process efficiency. New and improved pesticides on the other hand are constantly required. This, coupled 

Several arylsulfones are effective acaricides thus diphenyl sulfone is especially toxic to the eggs of the fruit tree spider mite and the 2,4,5-trichloro- and the 2,4,5,4 -tetrachloro derivative (tetradifon 23) are valuable acaricides.  

Sulfonamides also display antifungal action against rust diseases on cereals, but the action is rather limited. A -Acetylsulfanilyl hydrazide and derivatives had systemic antifungal action against wheat rust and were prepared by condensation of A -acetylsulfanilyl chloride with hydrazide hydrate.  

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Phospholipid molecules form bilayer films or membranes about 5 nm in thickness as illustrated in Fig. XV-10. Vesicles or liposomes are closed bilayer shells in the 100-1000-nm size range formed on sonication of bilayer forming amphiphiles. Vesicles find use as controlled release and delivery vehicles in cosmetic lotions, agrochemicals, and, potentially, drugs. The advances in cryoelec-tron microscopy (see Section VIII-2A) in recent years have aided their characterization [70-72]. Additional light and x-ray scattering measurements reveal bilayer thickness and phase transitions [70, 71]. Differential thermal analysis... 

It was further shown that such equations could be extended to a wide variety of amides and related compounds and even allowed the prediction of the degradation products of agrochemicals of the benzoylphenylurea type [13]... 

Computer-Aided Molecular Design Applications in Agrochemicals, Materials and Pharmaceuticals C. H. Reynolds, M. K. Holloway, H. K. Cox, Eds., American Chemical Society, Washington (1995). 

The current or potential iadustrial appHcations of microemulsions iaclude metal working, catalysis, advanced ceramics processiag, production of nanostmctured materials (see Nanotechnology), dyeiag, agrochemicals, cosmetics, foods, pharmaceuticals, and biotechnology (9,12—18). Environmental and human-safety aspects of surfactants have begun to receive considerable attention (19—21). 

T. F. Tadros, ed., Sufactants in Agrochemicals, Marcel Dekker, New York, 1992. 

From the point of view of appHcation, pharmaceutical fine chemicals constitute the largest part of all fine chemicals, both in terms of number of products and volume of sales. About 40—50% of the total fine chemicals sales comes from pharmaceutical fine chemicals about 20 to 25% are agrochemicals, and the rest belong to other categories. 

Many fluorinated, biologically active agents have been developed and successfully used in the treatment of diseases. The biological property of fluorinated organics has been further extended to applications in the agrochemical and pest management fields. 

D. Berg and M. Plempel, eds.. Sterol Biosynthesis Inhibitors—Pharmaceutical and Agrochemical Aspects, Ellis Horwood, Chichester, 1988. 

Herbicides are also sometimes classified according to mode of action, selectivity, registered uses, and toxicity. The ever-increasing importance of herbicides and other pesticides and agrochemicals to a wide range of users, regulators, and researchers has led to the development of multiple and extensive computer databases. The primary database resources contain collected information relevant to herbicides, and numerous resource pubHcations are available to those needing information on the various aspects of herbicides (2). 

National Agricultural Library database general coverage of U.S. agriculture active components of agrochemicals... 

W. Draber and T. Fujita, eds., National Approaches to Structure, Activity, andEcotoxicology of Agrochemicals, CRC Press, Boca Raton, Fla., 1992. 

D. R. Baker and co-workers, eds.. Synthesis and Chemisty of Agrochemicals, ACS Symposium Series, 355, American Chemical Society, Washington, D.C., 1987. 

Catechol is produced by coproduction with hydroquinone starting from phenol. Other techniques such as coal extraction remain marginal. The installed capacities (- 25,000 t/yr) are now sufficient to cover the demand. Catechol is mainly used for synthesis in food, pharmaceutical, or agrochemical ingredients. A specific appHcation of / fZ-butylcatechol is as a polymerisation inhibitor. 

Euiopean Directory of Agrochemical Products RSC Dialog European agrochemical products... 

As the most reactive and economical source of the acetoacetyl moiety, diketene is used as a valuable synthetic intermediate in the manufacture of acetoacetic acid derivatives and heterocycHc compounds which are used as intermediates in the manufacture of dyestuffs, agrochemicals, pharmaceuticals, and polymers. 

Liposomes. Lecithin, and mote specifically purified phosphohpids, ate used to produce liposomes (39) for the food (40), cosmetics, pharmaceutical, agrochemical, and technical fields. 

Microcapsules are used in a number of pharmaceutical, graphic arts, food, agrochemical, cosmetic, and adhesive products. Other specialty products also exist, thus the concept of microencapsulation has been accepted by a wide range of industries. In order to illustrate how microcapsules are used commercially, it is appropriate to describe a number of commercial microcapsule-based products and the role that microcapsules play in these products. 

Oxahc acid is used in various industrial areas, such as textile manufacture and processing, metal surface treatments (qv), leather tanning, cobalt production, and separation and recovery of rare-earth elements. Substantial quantities of oxahc acid are also consumed in the production of agrochemicals, pharmaceuticals, and other chemical derivatives. 

Uses of oxalic acid ia each region are summarized in Table 5 (58). The demand for agrochemical/pharmaceutical production and for separation/recovery of rare-earth elements in each region has been increasing. The use for marble polishing in western Europe is unique to the region. 

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