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Transcript of Chlorocarbon Compounds
Compounds Refrigerators The Science Behind Keeping Cool The History of the First Fridge Further Trouble with Chlorinated Compounds: PCB's PCB's, or polychlorinated biphenyls, are compounds used as electrical insulators and coolants. CFC's are not ALL that good Although CFC's increased home refrigeration, the means of cooling houses, and the production of aerosol sprays and Styrofoam..... they took a toll on the environment. Claudia Seguin Around 1851, James Harrison invented the first vapor compression cooling system for an Australian brewery. After successfully establishing land-based refrigeration, he attempted to transport meat and other necessities over seas. Two of the world's first refrigerated ships were the Frigorifique and the S.S Paraguay. Both of the ships "refrigeration" was maintained by water that was cooled by ice and was pumped throughout the ship in pipes. Fabulous Freons.... the ideal refrigerant molecules In order for a molecule to act as a refrigerant, it must liquify by compression and absorb large amounts of heat as it vaporizes.
SOME EXAMPLES that satisfy these conditions are.... ammonium, ether, methyl chloride, and sulfur dioxide.
Although all of the above compounds are useful, many were either poisonous, hazardous, or smelt terrible. So what did scientists do about this problem??? Thomas Midgley and Albert Henne discovered the advantages of using compounds of fluorine. They prepared molecules containing carbons with chlorine and fluorine instead of hydrogen. They were called... CHLOROFLUOROCARBONS or CFC's CFC's were seemingly nonexplosive, nonpoisonous, perfect refrigerants. CFC's are given the abbreviated name, Freon followed by a number which differentiates the structural formula. In 1930, Thomas Midgley held a demonstration of the physical properties of Freon for the American Chemical Society by inhaling a lung-full of the new wonder gas and breathing it out onto a candle flame, which was extinguished, thus showing the gas's non-toxicity and non-flammable properties. Naming of Freons The first digit is the number of carbon atoms minus one (in this case 0). The second digit is is the number of hydrogen atoms plus one. The last digit is the number of fluorine atoms. CFC's release into the lower atmospheric drift, and eventually rise into the stratosphere where they break down the ozone layer. Chlorine in
Chlorocarbons Affects Health and the Environment On average, for every chlorine atom that finds its way to the upper atmosphere, a CFC molecule will destroy 100,000 ozone molecules before it is deactivated. Not So Fun Fact What actions have been taken to protect the ozone layer? Through an international agreement known as the Montreal Protocol on Substances that Deplete the Ozone Layer, governments have decided to eventually discontinue production of CFCs, halons, carbon tetrachloride, and methyl chloroform and industry has developed more "ozone-friendly" substitutes. The ozone layer is constantly being created and broken, so in order for ozone layer to protect the earth, it must continually absorb ultraviolet radiation, #1 Chlorination of Water #2 Mustard Gas #3 Phosgene Gas Chlorine in the water system eventually leads to long-term environmental damage Mustard Gas was a military weapon used during WWI which causes choking, severe respiratory impairment, and/or eye damage Poisonous gas usually resulting in severe swelling of tissues in the lungs, which leads to suffocation. The Dark Side of Chlorine Not long after the manufacture of PCBs began, reports of health problems emerged. Over exposure to PCB's may lead to systematic PCB poisoning which causes liver failure and often cancer. One symptom of PCB poisoning is chloracne--when suppurating pustules appear on the face and body A devastating episode of human PCB poisoning occured when 1,300 residents of Kyushu, Japan ate rice-bran oil that had accidentally become contaminated with PCBs. The long term consequences included birth defects and liver cancer 15X the normal rate. Some of the most effective pesticides ever invented contain chlorine. One of which is DDT (dichloro-diphenyl-trichloroethane). Unfortunately, scientists were unsure if the dangers of DDT outweighed the potential benefits. Chlorine in Common Compounds or The effect of DDT on on wildlife is attributed not directly to DDT, but to its main product breakdown. Both DDT and the breakdown product are fat-soluble compounds that accumulate in animal tissue. This breakdown product inhibits the enzyme that supplies calcium to their egg shells. In the late 1940s, the steep decline in the population in many birds was noted. AGENT ORANGE More Compounds Chlorine Atoms Dioxin is considered the most lethal compound made by man. In 1976, an industrial explosion in Seveso, Italy, allowed the release of a quantity of dioxin Dioxin Hexachlorophene Hexachlorophene was routinely used on infants and was added to diapers, powders, and other baby toiletries, but in 1972, tests showed that its use led to brain damage and nervous system damage. Now it is banned from over the counter baby products because of its toxicity. DDT Agent Orange, a mixture of chlorine-containing herbicides, was used during the Vietnam war. Similar to the effect of DDTs on bird's eggshells, Agent Orange caused serious health problems that still affect Vietnam today such as....
defects, deficiencies, skin problems, and cancer in humans Chlorocarbons are not ALL bad... One small chlorine-containing compound proved to be a boon for medicine. At first, ether was used to induce narcosis (temporary unconsciousness). But later, Simpson discovered that the use of chloroform worked faster, smelt better, and was more efficient than ether. In the mid nineteenth century, chloroform anesthesia was readily accepted for surgical cases. Surgical anesthesia was universally recognized as a great advance, but its use in childbirth was controversial. In 1853, Queen Victoria delivered her 8th child with the assistance of chloroform. After royalty decided the compound was safe, it became the anesthesia of choice for childbirth in Britain. surprise, surprise.... As it turns out, chloroform(for all of its blessings to surgical patients) has a "DARK SIDE" It is known to cause liver and kidney failure, cancer, cornea of the eye, fatigue, nausea, irregular heartbeat...and the list goes on So nowadays working with chloroform requires protective clothing and equipment :) CHLOROFORM ...and the Effect of Chlorocarbons The irony of chlorocarbons is that those that have done the most harm seem also to be responsible for some of the most beneficial advances in our society. We now make hundreds of chlorine-containing organic compounds that are not poisonous, do not destroy the ozone layer, do not harm people, and have never even been used in gas warfare. (insert laughter here) haha I made a funny POSITIVE Impact of Chlorocarbons ...and yes, it does exist Some of the many advances thanks to chlorocarbons....... refrigerant molecules for long trips home refrigeration AIR CONDITIONING safe drinking water reduced amount of insect borne diseases anesthetics `