DDT

= **BY: ANTHONY LI - BLOCK D** =

__**CHEMICAL STRUCTURE**__

DDT, **IUPAC** name: 1,1,1-trichloro-2,2-di(4-chlorophenyl)ethane, is one of the most controversial organic pesticides in history. It is a white coloured, odourless, and has the appearance of small solid crystals. A molecule of DDT contains 6 carbon, 9 hydrogen, and 5 chlorine atoms. It also has an incredibly long **half-life** (15 years when in soil)

__**HISTORY**__
 * < == Properties == ||
 * < Molecular Formula ||< C14H9Cl5 ||
 * < Molar Mass ||< 354.49 g/mol ||
 * < Density ||< 0.99 g/cm³ ||
 * < Melting Point ||< 109 °C ||
 * < Boiling Point ||< 260°C ||

It was introduced in 1941 as a pesticide to control insects, mainly to control **malaria** and **typhus**. It was very successful in eliminating these diseases all over the world. However, it wasn’t available for farmers until 1945. Today, DDT is banned worldwide for agricultural use but it is still used limitedly for disease control in developing countries.



**__HOW IT IS MADE__**

DDT is produced by a reaction of 1 mol chloral (C2HCl3O) with 2 mol of chlorobenzene (C6H5Cl). It is then only able to **synthesize** into DDT by the presence of the catalyst sulphuric acid (H2O4S). While being synthesized, chloral is dissolved in the chlorobenzene and stirred in a constant cold temperature; with time intervals of acid being added. In the end the solid separates and the reaction mixture turns pasty


 * REACTION**: Cl3CCHO + 2 C6H5Cl à Cl3CCH(C6H4Cl)2 + H2O

__**HOW IT AFFECTS US**__


 * __ BENEFITS __**
 * It kills disease-causing organisms that are responsible for causing malaria, typhus, etc. It is also estimated that it saved the lives of over 50 million people


 * DDT can last for months after being applied on a surface.


 * It is very cheap and is able to kill any kind of pests/insects. Plus, it is low in toxicity in humans


 * __ HARMFULNESS __**
 * After being sprayed on crops, it begins by **bioaccumulating** in plants. The plants will get eaten by organisms, which can lead to transferring of the chemical all over the food chain until the top organism in the food chain has all the concentrations of the DDT. Also, it is stored in the fatty tissues of organisms that eat the plants


 * It affects the aquatic food chain by accumulating in plankton. (the process just like above)


 * When a bird consumes a DDT-affected plant, it will lay eggs that are extremely delicate with a thinned shell.


 * It needs to be used in a controlled manner or else it can be washed into rivers and streams, contaminating the water for organisms that depend on it.


 * It cannot be sprayed close to pregnant women or small children


 * There has also been studies that concluded DDT causes a increased risk for developing breast cancer and diabetes



__**INTERESTING FACTS**__


 * It was first synthesized in 1873 but it wasn’t until 1939 when its first pesticide properties was discovered by scientist Paul Hermann Müller


 * It is soluble in fats and organic solvents but insoluble to water


 * The chemical accumulation of DDT is measured in **parts per million (ppm)** and is considered toxic at 5 ppm



__**GLOSSARY**__

**IUPAC** - International Union of Pure and Applied Chemistry. They are known for the standard nomenclature in chemistry


 * Half-life** - The time it takes for something to eliminate one half of a substance that has been introduced to it


 * Malaria** - A parasitic disease caused by mosquito transfer


 * Typhus** - Disease caused by bacteria


 * Synthesize** - The preparation and production of reacting chemicals (usually organic) to produce a product or several products


 * Bioaccumulate** - The gradual build of synthetic and organic chemicals in living organisms

**Parts per million (ppm)** - measurement of chemical accumulation. (1 ppm means one particle of a substance mixed with 999 999 other particles)

**// SOURCES (Bibliography): //**
__Wikipedia.org__ Wikipedia Corporation. June 1 2010 http://www.wikipedia.org

__BC Science__ Edvantage Press and McGraw-Hill Ryerson June 2. 2010 [|http://bcscience.com/bc10/]

__Benefitsof.net__ Benefits Of. June 3 2010 http://benefitof.net/benefits-of-ddt/'

__Science Daily Website__ Science Daily June 3, 2010 http://www.sciencedaily.com/releases/2007/10/071009082406.htm

__Banned Insecticide__ 3Dchem. June 3, 2010 http://www.3dchem.com/molecules.asp?ID=90

__CBC Canadian Broadcast Corporation__. June 3, 2010 http://archives.cbc.ca/environment/natural_disasters/clips/7076/