Chapters :
  • Chemistry in everyday life – 03

  • TRICHLOROMETHANE (CHLOROFORM)

  • TRIIODOMETHANE (LODOFORM)

  • TETRACHLOROMETHANE (CARBON TETRACHLORIDE CCI4)
  • FREONS

  • DICHLORODIPHENYL TRICHLORO ETHANE (DDT)

  • METHANOL (CH3OH)

Chemistry in everyday life – 03

DICHLOROMETHANE (METHYLENE CHLORIDE)

  • METHYLENE CHLORIDE HARMS THE HUMAN CENTRAL NERVOUS SYSTEM. Exposure to lower levels of Methylene Chloride in Air can lead to slightly impaired hearing and vision. Higher levels of methylene chloride in air cause Dizziness, Nausea, Tingling and Numbness in the fingers and toes.
  • In humans, direct skin contact with methylene chloride causes intense burning and mild redness of the skin. Direct contact with the eyes can bum the cornea.

TRICHLOROMETHANE (CHLOROFORM)

  • Chemically, Chloroform Is Employed as A Solvent for Fats, Alkaloids, Iodine and Other Substances. The major use of chloroform today is in the production of the Freon Refrigerant R-22.
  • It was once used as a general anesthetic in surgery but has been replaced by less toxic, safer anesthetics, such as ether. As might be expected from its use as an anesthetic, inhaling chloroform vapours depresses the central nervous system.
  • Chronic chloroform exposure may cause damage to the liver (where chloroform is metabolized to phosgene) and to the kidneys, and some people develop sores when the skin is immersed in chloroform. Chloroform is slowly oxidized by air in the presence of light to an extremely poisonous gas, carbonyl chloride, ALSO KNOWN AS PHOSGENE. It is therefore stored in closed dark-coloured bottles completely filled so that air is kept out.

TRIIODOMETHANE (LODOFORM)

  • It was used earlier as an antiseptic, but the antiseptic properties are due to the liberation of free iodine and not due to IODOFORM ITSELF. Due to its objectionable smell, it has been replaced by other formulations containing iodine.

TETRACHLOROMETHANE (CARBON TETRACHLORIDE CCI4)

  • It is produced in large quantities for use in the manufacture of refrigerants and propellants for aerosol cans. It is also Used as Feedstock in the synthesis of Chloro- Fluorocarbons and Other Chemicals, Pharmaceutical Manufacturing, And General Solvent Use.
  • Until the mid-1960s, it was also widely used as a cleaning fluid, both in industry, as a degreasing agent, and in the home, AS A SPOT REMOVER AND AS FIRE EXTINGUISHER.
  • There is some evidence that exposure to carbon tetrachloride causes liver cancer in humans. The most COMMON EFFECTS ARE DIZZINESS, LIGHT HEADEDNESS, NAUSEA AND VOMITING, which can cause permanent damage to nerve cells. In severe cases, these effects can lead rapidly to Stupor, Coma, Unconsciousness or Death. Exposure to CCI4 can make the heart beat irregularly or stop. The chemical may irritate the eyes on contact.
  • When carbon tetrachloride is released into the air, it rises to the atmosphere and DEPLETES THE OZONE LAYER. Depletion of the ozone layer is believed to increase human EXPOSURE TO ULTRAVIOLET RAYS, leading to increased skin cancer, eye diseases and disorders, and possible disruption of the immune system.

FREONS

  • The chlorofluorocarbon compounds of METHANE AND ETHANE are collectively KNOWN AS FREONS. They are extremely stable, unreactive, non-toxic, non-corrosive and easily liquefiable gases. Freon 12 (CCI2F2) is one of the Most Common Freons in industrial use.
  • It is manufactured from TETRACHLOROMETHANE BY SWARTS REACTION. These are usually produced for aerosol propellants, refrigeration and air conditioning purposes. By 1974, total freon production in the world was about 2 billion pounds annually.
  • Most freon, even that used in refrigeration, eventually makes its way into the atmosphere where it diffuses unchanged into the stratosphere. In stratosphere, freon is able to initiate radical chain reactions that can upset the natural ozone balance.

DICHLORODIPHENYL TRICHLORO ETHANE (DDT)

  • DDT, the first chlorinated organic insecticides, was originally prepared in 1873, but it was not until 1939 that Paul Muller Of Geigy Pharmaceuticals in Switzerland discovered the effectiveness of DDT as an insecticide. Paul Muller was awarded the Nobel Prize in Medicine and Physiology in 1948 for this discovery.
  • The use of DDT increased enormously on a worldwide basis after World War II, primarily because of its Effectiveness Against the Mosquito that spreads malaria and LICE THAT CARRY TYPHUS.
  • However, problems related to extensive use of DDT began to appear in the late 1940s. Many species of insects developed resistance to DDT, and it was also discovered to have a high toxicity towards fish.
  • The chemical stability of DDT and its fat solubility compounded the problem. DDT is not metabolized very rapidly by animals; instead, it is deposited and stored in the fatty tissues. If ingestion continues at a steady rate, DDT builds up within the animal over time. The use of DDT was banned in the United States in 1973, although it is still in use in some other parts of the world.

ALCOHOLS, PHENOLS AND ETHERS 

  • Ordinary spirit used for polishing wooden furniture is chiefly a compound containing hydroxyl group, ethanol. The sugar we eat, the cotton used for fabrics, the paper we use for writing, are all made up of compounds containing -OH groups.  The simplest Hydroxy Derivative of Benzene is phenol.

METHANOL (CH3OH)

  • ,It also known as ‘Wood Spirit’, was produced by destructive distillation of wood. Today, most of the methanol is produced by catalytic hydrogenation of carbon monoxide at high pressure and temperature and in the presence of ZnO−Cr2O3 catalyst.
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