Chlorocarbon Compounds

           The Chlorocarbon compounds were the beginning of an era of refrigeration, where people didn’t need to worry about rooting food, and excruciating hot weathers. Human now had a source of refrigeration and the innumerous possibilities this represented took the world by storm, completely eliminating the previous cooling source, ice.  

             The refrigeration process involves liquid and vapor phases, in which a liquid evaporates, absorbing the heat of the surroundings. This vapor created goes through compression and goes back to the liquid state, re-evaporating again producing the cooling effect as the cycle of evaporation and compression continues to happen. For this process a refrigerant agent was then need, a substance that would go through the two physical changes. The two first vapor-compression refrigerators tests and successfully used were based either with ammonia or ether, and tests in long voyages, after some failures, both of them had proven to be quite successful transporting frozen meat from one point to the other. This transport of frozen merchandise had shown to be very important for the economic development of a lot of nations since it was possible to bring products to world markets.  

            Even though the ether and ammonia based vapor-compressing refrigerators had shown to be successful, they were not completely perfect since the refrigerant agents mostly used at that point most of the times had a tendency to decompose, to be poisonous, fire hazards, and smelled very bad. So, scientists started to look for other substances that fitted the boiling points criteria but did not a have the flaws of the previous ones. Thomas Migley and Albert Hennen noted that fluorine compounds have never been taken in consideration and started to test these compounds, preparing different molecules with different amounts of fluorine and chlorine atoms in place of hydrogen in carbon chains. The experiments were a complete success and Migley and Hennen had just produced the well-known chlorofluorocarbons, CFC’s (designated as Freons at the time), which had proven to perfect refrigerants and did not have any of the flaws of the previous refrigerant agents. With this big success the refrigeration industry blossomed. There was a huge increase of in home refrigeration, changing the way we dealt and looked at food. Heat sensitive medications and antibiotics could now be shipped around the world, with this compounds the air-conditioning industry flourished and people had a mean to fight the hot weather in tropical areas where the temperatures could be excruciatingly high, and CFC’s since this compounds reacted with almost nothing, they were perfect to serve as propellants in spray cans, and a lot of other uses continued to follow. CFC’s were being used and produced in innumerous areas and it seemed like these were miraculous and perfect substances. However, no substance is completely perfect, and later people would understand that this ‘perfect’ substance and negative effects that could affect the entire world population, and the planet itself. It is true that CFC’s do not react with most compounds, they are not broken with ordinary reactions, so the leaked CFC’s that go to the atmosphere will eventually rise to stratosphere and be ruptured by solar radiation. As we all know the ozone layer made of ozone molecules, O3 is also found in the stratosphere and is responsible for protection of planet earth against the ultraviolet rays from the sun that would greatly increase the temperature and damage all forms of life, increasing the damage to cells’ DNA promoting cancer and mutations. This ozone layer has her own self-management of quantities, never being too much or lower than it should, since it is constantly being made and broken, maintaining a balance. However it was recently found that CFC’s are a threat to this layer, and consequently a threat for human survival. The broken CFC’s due to solar radiation release chlorine atoms which will then react with ozone molecules breaking them in ClO and oxygen molecules, product which will then produce even more chlorine. This creates a very fast destruction of ozone molecules, representing a great danger to the ozone layer. Even when the real dangers of CFC’s were known, their ban wasn’t immediate. The industry of this compounds was so profitable that people didn’t want to give it up, and only years later did its use start to decrease, even though not completely.  

            Just like CFC’s most chlorine containing compounds have shown miraculous and perfect results, to then its dangerous and life-threating effects to be understood and feared. An example of this is the chlorine molecule itself, which was used in the cleaning of water, a very important job, in which chlorine was the cheapest mean to do this process. However as it was found later, chlorine is poisonous which could be very dangerous. A lot of WWI poisonous gases like, mustard gas and phosgene, are made from chlorine, they are chlorine containing organic compounds which adds to their image as ultimately dangerous compounds.

           

            PCB’s, polychlorinated biphenyls, were most commonly used in the late 1920s, in which the hydrogen atoms were substituted by chlorine atoms in the biphenyl main chain. These compounds were again highly prized Chlorocarbon compounds, since they were perfect electrical insulators used in many areas, and its stability at high temperatures and their lack of flammability, made it loved by the industry. However the dark side of this compound was found when health problems started to show on people that worked in the production of this compounds and its poisonous and scary character was found, and its stability which was so loved, proved to be an even more dangerous factor since there was a big risk of bioaccumulation which could endanger a lot of lifes.

            Another very used Chlorocarbon compounds are the DDT, the dioxin, and hexachlophene. All this compounds used as pesticides and germicides were thought to be very useful since their stability was again seen as something good, because it would stay in the air longer and this was believed to be a good thing to kill  the bugs, making the compounds good pesticides. But all this compounds have very strong side effects, threating both animals and humans, which led to its eventual ban.

            Chloroform was another Chlorocarbon compound that changed the lifes of people, either for worse or for the better, having big advantages for medicine but also strong side effects. This compound was the substitute of ether in surgery, serving as an anesthetic and proportioning unconscious and painless surgeries. This compound had been preferred over ether because it wasn’t as flammable as ether and the recovery of the patient when using chloroform was faster and less uncomfortable. Chloroform became the an universally recognized anesthesia, and the anesthetic of choice in Britain and much of Europe. However, as much as it was revolutionary for medicine, it was also found out the strong flaws of chloroform which was found out to increase the risk of cancer, and cause liver and kidney damage, between many other negative effects, but at the time this compound was a blessing, and the negative effects seemed small in comparison to its anesthetic power that was so adored by many.

            As the authors have shown throughout the chapter, there are innumerous Chlorocarbon compounds that have affected our lifes. They have such miraculous effects, and even stronger negative effects, able to endanger the whole planet. Such powerful compounds have for sure changed the world, either for the better or worse, but for sure a lot of the things we have now and the especially, the refrigerating commodity, is all due to this chlorine containing compounds. Chlorocarbon compounds, most probably are still used today, even though most of the times they are avoided due to the knowledge over its big dangers, so they are not as important since people try to avoid it.