Chlorocarbons and Malaria

Chlorocarbon Compounds

     Ice has been used to keep things cool since 2000 B.C., based on the principle that as ice melts it absorbs heat from its surroundings. Refrigeration uses liquid and vapor phases rather than liquid and solid, and as the liquid evaporates it absorbs heat from the surroundings. A refrigerant is a compound that undergoes the evaporation and compression cycle that occurs in a refrigerator. Ether was used as to show the cooling effect of refrigerants in 1748, but it wasn't until 1851 that James Harrison created an evaporation-compression refrigerator based on ether. In 1859, Ferdinand Carre used ammonia as a refrigerant. James Harrison decided to transport meat from Australia to Britain in 1873 using his ether-based refrigerator, but his system did not work out at sea. The first successful trip of a refrigerated ship occurred in 1877, with ammonia as the refrigerant. Refrigerators were not available for home use until 1913.

CFCs are known to break down the ozone layer

     Thomas Midgley Jr. and and Albert Henne created different molecules with one or two carbon atoms and various numbers of fluorine and chlorine instead of hydrogen atoms. The compounds they produced, chlorofluorocarbons (CFCs), were nontoxic, nonflammable, inexpensive, and very stable. These Freons had coded names- the first number was the carbon atoms minus one, the second was the hydrogen atoms plus one, and the third digit was the number of fluorine atoms. The CFCs were the perfect refrigerants, and their stability allowed them to also be used to propel substances through spray cans. However, the stability of these compounds caused them to drift through the atmosphere for years without being broken down. Sherwood Rowland and Mario Molina found that chlorine accelerates the breakdown of the ozone layer by removing an oxygen atom from the ozone, leaving an oxygen molecule behind. This drastic environmental effect caused a ban of CFCs- hydrofluorocarbon and hydrochlorofluorocarbon molecules are used instead.

     Polychlorinated biphenyls (PCBs) have chlorine atoms in place of where the hydrogen atoms would be in the biphenyl molecule, and they were used for electrical insulators and coolants for transformers, capacitators, circuit breakers, and reactors. However, workers at PCB plants began experiencing chloracne, a skin condition that is one of the first symptoms of PCB poisoning. PCBs are one of the most dangerous molecules to ever be produced. Dichloro-diphenyl-trichloroethane (DDT) was first produced in 1874, but its insecticide properties were not known until 1942. In October of 1846, William Morton used ether to induce narcosis- a temporary unconsciousness- during surgeries. James Young Simpson tested different compounds for anesthetic abilities, and chloroform passed. It was more effective for surgical anesthesia, however it was known to cause kidney and liver damage, and possibly cancer.

Molecules Versus Malaria

     Malaria means "bad air" because it was previously believed that the illness was caused by poisonous vapors and mists in the air. The disease is caused by a microscopic parasite, and there are four that infect humans: Plasmodium vivax, P. falciparum, P. malariae, and P. ovale. The most deadly is falciparum malaria, but they all produce the common symptoms. Malaria is transferred by the anopheles mosquito, and it develops in the victim's liver before entering the bloodstream. There have been three different molecules used to try to control the disease- quinine, DDT, and hemoglobin.

     Quinine was isolated for the first time in 1792- in an impure form. In 1820, Joseph Pelletier and Joseph Caventou extracted quinine and purified it. Quinine comes from the quinoline molecule, and a few derivatives of this molecule were shown to have treated acute malaria in the 1930s. The best synthetic option was chloroquine, but strains of the parasite that are resistant to chloroquine have spread. In 2001, Gilbert Stork and his coworkers took a quinoline derivative and synthesized quinine from it. The main uses for quinine today are tonic water, quinine water, and other drinks. It is also used to produce a heart medication called quinidine.

How malaria is transmitted

     In 1880, Charles-Louis-Alphonse Laveran found that blood of malaria patients contained cells that are a stage of the malarial protozoa. In 1891 it was possible to identify the specific malaria parasite by dying the cells. Ronald Ross discovered another stage of the parasite in the gut of the anopheles mosquito in 1897, proving that mosquitoes were the method of transmission. There are several ways to break the disease cycle- killing the merozoite stage in the liver and blood, preventing mosquito bites, killing adult mosquitoes, or preventing the breeding of mosquitoes. It is very difficult to avoid mosquitoes, so the best method is to use strong insecticides, like DDT. People who live in malarial areas and carry the sickle cell trait have a certain degree of immunity to malaria. Hemoglobin transports oxygen to the body, and gives red blood cells their red color. Hemoglobin consists of amino acids arranged in sets of two identical strands. Patients with sickle cell anemia have a valine as the sixth amino acid instead of glutamic acid. It is not known how it provides immunity against malaria, but this structure inhibits the life of the malaria parasite.

MNCOAS

     

Morphine, Nicotine, and Caffeine

     The opium poppy consists of 24 alkaloids, the most prominent being morphine. Morphine was isolated for the first time by Friedrich Serturner in 1803. Named after the Roman god Morpheus, the god of dreams, it numbs the senses and induces sleep. The structure of morphine was not known until 1925, but morphine and similar compounds are the most effective painkillers known today. However, the painkilling or analgesic effect is related to addiction, making these compounds very addictive. In 1898, Bayer and Company put morphine through the acylation reaction, with hopes that it would have the same results as aspirin. This diacetylmorphine was marketed as Heroin, and it is "one of the most powerfully addictive substances known". Bayer thought that this heroin was free from the side affects and addictive properties of morphine, and it was marketed as a "super aspirin". However, once they realized the side affects, the company stopped advertising the product. Rather than interfering with nerve signals, morphine blocks the pain receptors in the brain, mimicking the action of endorphins.

     Tobacco contains at least ten alkaloids, but the main one is nicotine. Nicotine stimulates the heart and central nervous system at first, then eventually becomes a depressant. The nicotine molecule heightens transmission of neurological impulses by forming a bridge at the connection of two nerve cells. However, this transmission site will eventually become obstructed, and the stimulating effects of the nicotine will cease. Nicotine can also be deadly when taken in larger doses, and it is more potent when absorbed than ingested because the stomach acids break some of it down. When smoking, the nicotine is oxidized into less toxic forms from being burned at high temperatures. Nicotine is a natural insecticide, but nicotinic acid is an essential B vitamin. The name nicotinic acid was later changed to niacin because bakers did not want their bread to be commercialized under a name similar to nicotine.

Structure of Caffeine

     Caffeine stimulates the central nervous system and is one of the most studied drugs worldwide. It is naturally found in coffee beans, tea leaves, and other plants, typically from South America. Caffeine blocks adenosine's effect in the body, especially in the brain. Caffeine does not actually wake people up, it just prevents adenosine from inducing sleep. When caffeine takes up the adenosine receptors in the body, a caffeine buzz is experienced: increased heart rate occurs, some blood vessels constrict, and some muscles are more easily contracted. Caffeine can be fatal at a dose of ten grams. It is an addictive substance, and withdrawal symptoms include headache, drowsiness, fatigue, nausea and vomiting. Chocolate contains anandamide, which binds to the same receptor as THC. Chocolate was Europe's first encounter with caffeine.

Oleic Acid

     Olea europaea (the olive tree) is the only species of the Olea family that is grown for its fruit, and has been cultivated for anywhere between five and seven thousand years. Oils have been obtained from many plants, and they have been valuable for food, medicine, lighting, and cosmetic purposes. They are liquid at room temperature and have more unsaturated fatty acids than saturated ones. Oleic acid is the main fatty acid in olive oil- with eighteen carbons, it is monounsaturated. Olive oil's low proportion of polyunsaturated fatty acids gives it a longer shelf life than almost any other oil. It also contains vitamins E and K, antioxidants that aid in preservation.

     Soap was most likely an accidental discovery, when people cooking over wood fires noticed the fats and oils that dripped from food to the ashes created a substance that made a foamy lather in water. Saponification is the reaction that occurs when triglycerides react with alkalis- this is where the name soap comes from. Soap was mainly used for washing clothes, while personal hygiene included rubbing the body with a mix of olive oil and sand, then scraping it off. England began the commercial production of soap in the 14th century. By the end of the 18th century, Nicolas Leblanc designed a method to create soda ash from common salt. Soap molecules have one end with a charge that is soluble in water, and another end that is soluble in fat, oils and grease.

Salt

     The main methods to produce salt are by evaporating sea water, mining rock salt, and boiling salt solutions from brine springs. In 1887, Svante August Arrhenius proposed that oppositely charged ions were responsible for the properties and structure of salts and salt solutions. He demonstrated that the more salt is dissolved into solution, the more concentrated the ions need to be to carry electric current. Arrhenius won the 1903 Nobel Prize for his electrolytic dissociation theory. Sodium chloride's solubility makes salt a good preservative because it removes the water from a product, creating a harder environment for bacterial growth. More salt was used for preservative measures than to enhance flavor of foods.
     The ions from salt have a major role in balancing the electrolytes between the cells and the surrounding fluid in the body. The average human body contains four ounces of salt, but that salt is constantly lost through urine or perspiration. The salt must be replaced, and excess salt must be excreted. It is not good to have either too much or not enough salt. Taxes were imposed on salt since ancient times, and in 1825 the United Kingdom became the first to repeal the tax. The taxes were removed, not because of the resentment they had aroused among the working class, but because salt became a very important starting material during the Industrial Revolution. In 1791, Nicolas Leblanc created a method to form sodium carbonate from sulfuric acid, coal, salt, and limestone. In the 1860s, Belgium brothers Ernest and Alfred Solvay designed an improved process to turn sodium chloride into sodium carbonate by using ammonia gas and limestone. This process is still used for synthetic soda ash production today. Caustic soda (sodium hydroxide) can be produced through electrolysis- passing an electrical current through a sodium chloride solution.

Drugs, Pills, and Witchcraft.. Oh My!

Wonder Drugs

Bayer Aspirin

     Edward Jenner demonstrated the production of an artificial immunity to disease for smallpox in 1798. Felix Hofmann, from the Bayer company, began investigating compounds related to salicylic acid in 1893. Salicylic acid can be produced from the flower of meadow-sweet, Spiraea ulmaria, and it is used to reduce fever and inflammation. However, it irritates the lining of the stomach, making it less valuable as medicine. Hofmann gave acetyl salicylic acid to his father, who had rheumatoid arthritis. This derivative of salicylic acid has an acetyl group instead of an OH group. In 1899, Bayer marketed packets of "aspirin" in the powdered form. The name comes from the combination of acetyl and Spiraea ulmaria. Aspirin has become the most popularly used drug for illness and injuries, with over 40 million pounds being produced every year in the United States.
     Paul Ehrlich had a theory that if one microorganism absorbed a dye while another did not, then a toxic dye could kill only the tissue that absorbs it, leaving the other tissue damage-free. He was searching for his "magic bullet", as he called it, and it was a dye that would target the tissue that absorbed it. After testing 605 chemicals, Ehrlich found a safe and reasonable compound in 1909. "Number 606", as it was called, was an aromatic compound that contained arsenic, and worked at targeting the spirochete that causes syphilis. The following year, Hoechst Dyeworks marketed this compound with the name "salvarsan". In the 1930s, Gerhard Dogmak used protonsil red to treat his daughter, who had a major streptococcal infection. The dye was effective because, in the body, protonsil red breaks down into sulfanilamide, which has been created in various forms between 1935 and 1946. These molecules, known as sulfa drugs, are active against bacterial infection, but they are not technically antibiotics. Antibiotics originate from microbes, while sulfanilamides are man made. However, the term antibiotic has come to describe any substance that kills bacteria.
     Louis Pasteur was able to show that a microorganism could be used to kill another in 1877. In 1928, Alexander Fleming was studying staphylococci bacteria, when he found that mold had contaminated his cultures. This mold was from the Penicillium family, and it became transparent and disintegrated. Fleming performed tests, and his results showed that the mold produced a compound that was antibiotic toward the staphylococcus batceria. However, the first clinical trial for penicillin was not until 1941. By 1943, pharmaceutical companies in America were producing approximately 800 million units of penicillin. In 1944, monthly production of the antibiotic was over 130 billion units. The structure of penicillin was unknown until 1946, and synthetic penicillin was only produced in 1957.

The Pill

     A contraceptive molecule, norethindrone, had a major role in society upon its emergence in 1960. "The pill" as it was known, was the first oral contraceptive. It is a steroid, but not in the sense of athletic performance enhancers. The first isolation of testosterone occurred in 1935 from ground up bull testes. The first isolation of a sex hormone was that of estrone in 1929 from the urine of pregnant women. The difference between male and female sexual characteristics lies in the molecular structure of the hormones. Female characteristics will become evident if the hormone has one less CH3, an OH instead of a double bonded O, and more carbon double bonds. Progesterone suppresses further ovulation when a woman is pregnant, so chemical contraception was based off an outside source of progesterone. However, natural progesterone has to be injected because it reacts with stomach acids, and finding sufficient amounts of progesterone in animals is difficult. Artificial progesterone that could be taken orally was synthesized.

Marker's process of isolating steroid system

     Russell Marker intended to develop an affordable way to produce cortisone. He knew that various plants consisted of compounds containing steroids, and there were more of them than in animals. Marker began working with the sarsasaponin molecule, a saponin that is found in the sarsaparilla vine. When the three sugars are removed from the molecule, a sarsasapogenin is left behind. Marker isolated the steroid system from the sarsasapogenin, and the addition of a few steps to this process allowed the development of synthetic progesterone. Although he destroyed his laboratory notes and experiments in an attempt to remove his name from the field of chemistry in 1949, Marker's work is known for making birth control pills possible.
     Carl Djerassi used the Marker degradation to demonstrate that cortisone could be produced from diosgenin, then syntheszed estrone and estradiol from diosgenin as well. He wanted to produce an artificial progestin, which would have similar properites as progesterone but could be taken orally. The pill was designed for women who had a history of miscarriage, not to be used as a contraceptive pill. In 1951, Djerassi and his team patented norethindrone, a molecule that was eight times more powerful than progesterone.
     Margaret Sanger was arrested for providing contraceptives to immigrant women in 1917. Katherine McCormick helped Sanger smuggle illegal contraceptives into the United States, and also provided financial support for the birth control cause. Gregory Pincus was challenged to find a contraceptive that worked perfectly, and found that norethynodrel (later called Enovid) fit the requirements. He tested this molecule and saw that it worked 100 percent effectively to prevent ovulation. The field trials for the molecule were held in Puerto Rico, and out of more than 2,000 volunteers, the failure rate was only one percent. Although it is much easier to prevent ovulation of a monthly egg than production of millions of sperm on a daily basis, molecules are being investigated as a possible birth control pill for men.

Molecules of Witchcraft

     In the middle of the 14th century, any magic that was performed outside the church was considered to be Satan's work. Witches were believed to be in a pact with the devil, and by the middle of the 15th century, traditional rules of law no longer applied to the trials of witches. Accusations were considered evidence, and torture was a routine occurrence. Many accused "witches" were women who were herbalists, who used plants to heal and provide relief. William Withering used foxglove extracts to treat congestive heart failure in 1795. These cardiac glycosides can reduce heart rate, and regulate and strengthen the heart beat. Alkaloids are plant compounds that contain nitrogen, affect the human central nervous system, and they are typically very toxic. "Flying salves" were ointments that were believed to promote flight, and they were made from plant extracts such as mandrake, belladonna, and henbane. The alkaloids present in the extracts are not water soluble, so they would be dissolved in fat or oil and applied as an ointment.

Visual effects of LSD

     In any disaster, the blame was placed on elderly women. They were easy targets because they could no longer have children and they may not have had any family support. These women often lived on the outskirts of town, and lived in extreme poverty, relying on their herbalist skills. These qualities made them susceptible to the accusations of witchcraft. Ergot poisoning had a drastic effect on populations, as the grains would become infected with the fungus. It is believed that ergotism had something to do with the beginning of the Salem witch trials in Massachusetts. Young people are more vulnerable to infection, and the first "bewitched" victims were girls and young women.
     In 1938, Albert Hofmann created his 25th derivative- lysergic acid diethylamide LSD-25. Nothing appeared to be exceptional about the molecule's properties. However, in 1943, Hofmann again created this derivative (LSD) and unintentionally experienced the first "acid trip". Since LSD cannot be absorbed through the skin, Hofmann was believed to have transferred it from his fingers to his mouth. The Sandoz company marketed LSD as a psychotherapy tool in 1947. In the 1960s, it became a very popular drug for people worldwide.

Dyes

Dyes

     It is believed that the extraction of dyes and dyestuffs may have been the first attempt at chemistry, occurring as early as 3000 B.C.. The dyes were typically extracted from plants, and the extraction processes were often complicated. Although they were highly desired, the early dyes had problems- they did not adhere to untreated fibers, they faded quickly, and they were hard to obtain. Blue was a very desired color, but it was very difficult to obtain because blue shades are not commonly found in plants. However, Indigofera tinctoria was a major source for indigo, the blue dye. The leaves of the indigo plant are not naturally blue, but after being fermented under alkaline conditions and oxidized, a blue color appears. Although blue was valuable, the most expensive dye was Tyrian purple, and it was often restricted to wear by the king or emperor only. This dye is a dibromo derivative of indigo- an indigo molecule with two bromine atoms- and is obtained from the mucus secreted by many species of marine mollusks. Greek mythology credits Hercules with the discovery of Tyrian purple when he noticed that his dog's mouth turned purple after eating shellfish. Tyrian purple was so desired, that by 400 A.D., the shellfish that produced it were almost extinct. Syntheitc indigo was not available until the end of the nineteenth century, when German chemist Johann Friedrich Wilhelm Adolf von Baeyer investigated the structure of indigo and found a way to make it from abundant materials. However, it wasn't until 17 years later that synthetic indigo, marketed by Badische Anilin un Soda Fabrik (BASF), was ready for commercial use.

     Dyes are organic compounds of color that absorb certain wavelengths of visible light. The molecule's absorption and reflection of certain wavelengths depends on the amount of conjugated bonds. Pigments are inorganic materials that are used for color, and they are completely unrelated to conjugated bonds. Synthetic dyes were created in the late 1700s, starting with picric acid- a molecule used in World War I munitions. It produced a strong yellow color, but it was difficult to obtain and potentially very explosive. By 1856, William Henry Perkin created an artificial dye at the age of 18. This dye was called mauve; it was a purple that remained colorfast and did not fade. BASF was established in 1861, and in 1868 Carl Graebe and Carl Liebermann created the first synthetic alizarinn. Hoechst was established a year after BASF and also synthesized alizarin. Bayer and Company, though most famously known for aspirin, was originally set up in 1861 to produce aniline dyes. After World War I, the economy and industry conditions in Germany plummeted, so the chemical companies formed a conglomeration known as IG Farben. During World War II, the company contributed to the Nazi Party and took control of chemical plants in countries occupied by Germany. After the war, IG Farben's growth was stopped, and the companies split into Bayer, Hoechst, and BASF again.

Isoprene

Isoprene

     Although rubber has been known about for centuries, it has only been essential to civilization for the past 150 years. Indian tribe is from the Amazon basin are credited with the first use of rubber. Christopher Columbus saw Indians in Hispaniola playing with high-bouncing balls made from a tree gum. He observed that they bounced better than the balls in Spain, and took a sample of the material home. The rubber latex was not suited for the environment in Europe, as it would become hard and brittle during the winter and sticky and smelly in hot weather. Charles-Marie de La Condamine of France was hired by the French Academy of Sciences to see if this substance had a use. He traveled to the South American jungle, and saw Omegus Indians from Ecuador collecting white sap from the caoutchouc tree (the material the. alls were made from). The Indians then held the sap over smokey fire, and molded it into various shapes. La Condamine's raw sample, however, was not preserved by smoking, so it arrived in Europe as a smelly mass that could not be used. Latex is a colloidal emulsion, meaning it is "a suspension of natural rubber particles in water".

Cis form

Trans form

     Natural rubber is a polymer of isoprene, the smallest repeating unit of polymer, which contains five carbon atoms. Michael Faraday performed the first experiments on rubber, and in 1826 he determined that the chemical formula for rubber is a multiple of C5H8. Isoprene was able to be distilled from rubber by 1835, which suggested that isoprene was composed of repeating C5H8 units. Isoprene has cis and trans structures, which create major differences in the properties of the molecule. When isoprene molecules are arranged in the cis form, the resulting rubber is very elastic. However, if the molecules are in a trans arrangement, the resulting polymer has properties vastly different than those of rubber. This polymer naturally occurs in balata and gutta-percha. These materials are both made from latex, and they can be melted and molded. Unfortunately, after being exposed to the air for a while, they become hard.
     Charles Macintosh used naphtha to convert rubber into a fabric coating in 1823, which was used to produce waterproof coats. However, the popularity of these "macintoshes" (raincoats) decreased when people saw that they became brittle in the winter and melted in the summer. The word rubber was created by Joseph Priestley in 1770, when he discovered that caoutchouc rubbed out pencil marks better than the moist bread method previously used. Around 1834, Charles Goodyear, American inventor and entrepreneur (but mostly inventor), had an idea that mixing rubber with a dry powder would help to absorb the extra moisture that made it so sticky in the heat. Goodyear began experimenting with different substances, but nothing worked. In the winter of 1839, he was experimenting with powdered sulfur and rubber when he accidentally dropped some of the mixture on a hot stove. Goodyear was surprised to see that the heat and sulfur changed rubber the way he had hoped. After continued experiments with adding sulfur and heat to rubber, Goodyear finally created a rubber that remained elastic, tough, and stable in any weather. 

     Goodyear did not know why rubber was affected by heat and sulfur in this way, but he named his process "vulcanization" after the Roman god of fire. It wasn't for at least another 70 years until Samuel Shrowder Pickles proposed that rubber was a polymer of isoprene in a linear arrangement. The addition of sulfur created cross-links through the bonds between sulfurs. Heat helped form these bonds, which hold rubber molecules in place while allowing them to remain flexible.

     In 1876, Henry Alexander Wickham left the Amazon on a ship with 70 thousand seeds of Hevea brasiliensis, the major source of rubber latex. He arrived at the home of Joseph Hooker, a famous botanist. A propagating house was set up, and the seeds were planted. Western Malaysia is the home of the first two rubber plantations. By 1896, London received Malayan rubber, and Britain had 10 million rubber trees by 1907. Leopold II of Belgium colonized central Africa in the 1880s, and demanded red rubber as ransom from the African people. Those who did not collect enough rubber often had their hands cut off.
     98 percent of the world's rubber supply was being produced by plantations in Southeast Asia by 1932. After the attack on Pearl Harbor in 1941, President Franklin Delano Roosevelt established a commission to search for solutions to the wartime rubber shortage. The commission concluded that without securing a vast amount of rubber, the mission would fail. Roosevelt determined that dandelions would produce small amounts of questionable latex. The best solution was to produce synthetic rubber. An isoprene polymer similar to rubber is found naturally in latex. It is known as "chicle", and it had been used for chewing gum since ancient times. Chicle was introduced to the United States in 1855, when General Antonio Lopez de Santa Anna was exiled from Mexico. He had hoped to sell chicle to American rubber interests to earn money to raise a militia and reclaim his presidency of Mexico. Santa Anna worked with Thomas Adams, but they could not vulcanize chicle or blend it with rubber. However, Adams remembered its use as chewing gum, and he produced flavored chewing gum based on chicle. This was the start of the chewing gum industry.
     The technology to create synthetic rubber came from Germany. When the Allies blockaded Germany's supply of natural rubber during World War I, the German company IG Farben began producing rubber-like products, including styrene butadiene rubber (SBR). In 1929, the Standard Oil Company in New Jersey partnered with IG Farben, with an agreement that Standard Oil received access to specific IG Farben patents, including the one for SBR. IG Farben did not have to disclose all technical details, and in 1938 the Nazi government told the company not to give the United States any information on the rubber-making process. However, IG Farben eventually gave Standard Oil access to the patent under the belief that it did not have enough information for the United States to make their own rubber. They were wrong, and by 1945 the United States was producing over 800,000 tons of rubber- the second greatest feat of engineering (after the atomic bomb). In 1953, Karl Ziegler and Giulio Natta were able to independently develop processes that created either trans or cis double bonds, depending on the catalyst that was used. This made it possible to synthetically produce natural rubber. Ziegler and Natta received the Nobel Prize in chemistry for their work.

The Many Uses of Phenol(s)

Phenol

     Phenol, the first completely man-made polymer, was created about 25 years prior to Du Pont's nylon. This compound kicked off what is known as the Age of Plastics. Phenol is known to have links to orchids, surgical practices, endangered elephants, and photography. It has played an important role in advancements that would change the world.

     In 1860, hospitals were very dark and unsanitary, and people would only agree to surgery as a last resort. A large portion (40 percent) of amputees would die from "hospital disease", and in army hospitals it was 70 percent. The lack of sterilization in hospitals caused the majority of wounds to become infected, and bacteria could easily spread from patient to patient. The miasma theory was supported at the time, which was a belief that toxic gases from drains and sewers would carry through the air to other patients after a patient becomes infected. Treatments prescribed for miasma gases included salicylic acid, thymol, carbon dioxide gas, bitters, zinc sulfate, boracic acid, and raw carrot poultices. These treatments were rarely effective, and their occasional success could not be replicated.

     

Joseph Lister was born in Yorkshire in 1827, and received his medical degree from the University College in London. He was a surgeon at the Royal Infirmary in Glasgow in 1861, and he was also a professor of surgery at the University of Glasgow. Lister believed the hospital disease was caused by something microscopic in the air rather than poisonous gases. He found that "The Germ Theory of Diseases" by Louis Pasteur applied to his ideas. Pasteur considered germs to be everywhere, and his experiments showed that germs could be killed by boiling. Lister knew that he couldn't boil the doctors and patients, so he settled on carbolic acid to sanitize surfaces. One day, an eleven year old boy came to the hospital with a compound fracture, which posed high risks for infection. Lister cleaned the area around the broken bone with lint covered in carbolic acid. He used a surgical dressing made of layers of linen soaked in carbolic solution, then he covered it with a metal sheet to reduce evaporation of the carbolic acid. The boy's wound healed quickly, without any occurrence of infection. Lister later performed the same procedures on other patients, producing the same results. This convinced Lister that carbolic acid was effective at preventing infections. He began using it as an antiseptic in all of his surgical procedures in August 1867. Crude carbolic acid burned the skin, but Lister managed to obtain phenol, the main constituent of carbolic acid, in the form of white crystals.

Phenol Structure

    

     Phenol contains a benzene ring with an attached OH group. It is a simple aromatic molecule, and while it is very soluble in oil, it is only somewhat water soluble. Lister formed a "carbolic putty poultice" by mixing phenol with linseed oil and whitening. He would then spread the resulting paste over a wound to provide a barrier to the bacteria. A solution of phenol in water was used to clean the surgical tools, the skin around a wound, and the surgeon's hands. It was even sprayed onto incisions during operations. Although it was evident that the carbolic acid had a positive effect on patient recovery, Lister believed that he had yet to achieve complete antiseptic conditions during surgeries. In order to sanitize every particle in the air, he created a machine to constantly spray a mist of carbolic acid solution. Although this machine helped prevent contamination from airborne germs, it had harmful effects on the people in the operating room. Phenol is toxic, and it caused bleaching, numbing, and cracking of the skin. Inhalation of the phenol spray led to illness. By 1878, these techniques were used worldwide. However, phenol is no longer used as an antiseptic due to its toxicity and harmful effects.
     Phenol refers to a group of related molecules that have a benzene ring with an OH group, not just Lister's antiseptic. Although there is only one "phenol" itself, there are hundreds of thousands of phenols. Man-made phenols can be used as antiseptics, and picric acid, once used as dye, is explosive. Phenols also occur naturally. Molecules such as capsaicin, zingerone, eugenol, and isoeugenol (from the spices chapter) are classified as phenols. Other natural phenols include vanillin (from vanilla) and tetrahydrocannabinol (THC) in marijuana, and they usually have at least two OH groups. Gossypol is toxic and it is considered a polyphenol because it has six OH groups and four benzene rings. Epigallocatechin-3-gallate is a phenol found in green tea, and it has even more OH groups.
     Although there are many phenols in the world, the one with the most impact is the parent molecule, phenol itself. At the time of Lister's carbolic acid experiments, ivory was becoming a common material for combs, piano keys,cutlery, buttons, and more. The problem with this is that many elephants were being killed for their tusks, making ivory scarce and expensive. The decreasing elephant population caused concern, because the game of billiards was becoming very popular. The balls for this game must be cut from flawless animal tusk, because they require high-quality ivory in order to roll properly. In the late 19th century, billiard balls were made from other materials- bone dust, wood pulp, cotton paste with a hard cellulose-based resin, and eventually celluloid.
     A Belgian immigrant to the United States, Leo Baekeland, created the first synthetic version of what we now know as plastic in the early 1900s. This invention sparked the beginning of the Age of Plastics. Baekeland received his doctorate at the University of Ghent at the age of 21. His decision to emigrate to the New World appeared to be a mistake at first, and he was almost bankrupt in 1893. Baekeland saved himself by meeting with George Eastman, the founder of Eastman Kodak, a photographic company. Baekeland offered to sell Eastman a new type of photographic paper he created, which would allow people to easily develop their photos. Eastman was so impressed that he paid $750,000, which allowed Baekeland to open a lab next to his home. Baekeland then turned his focus to making a synthetic form of shellac, which is used to preserve wood. His approach was to react phenol with formaldehyde, which produced bad results when combined in previous attempts. In 1907, Baekeland created a reaction where he could control pressure and heat, and he produced a liquid that hardened into a transparent, amber-colored solid in the shape of the mold it was poured into. He called this substance Bakelite, and it was able to hold its shape when exposed to high temperatures. This material was very superior when used as an electrical insulator, and it did not react with water, sunlight, salt air, or ozone. It did not easily become degraded or cracked. Bakelite was the perfect material for billiard balls, although it was not Baekeland's intended purpose. All billiard balls that were not made of ivory were made of Bakelite by 1912, and the material was later applied to many other everyday items- telephones, plates, fountain pens, radios, pipe stems, glasses, kitchen equipment, decorations, etc.
     Demand for vanillin has exceeded the supply produced by the vanilla orchid, so a synthetic vanillin is manufactured. It comes from the "waste pulp liquor" from treatment of wood pulp when making paper. This waste liquor is mainly composed of lignin, which, when broken up, can form vanillin. Although synthetic vanillin is pure vanillin that is from a natural source, it lacks the traces of other compounds that the vanilla bean has, which help produce the flavor of true vanilla.
     Phenol has had a major role in shaping the world we live in today. It has made antiseptic surgery possible, improving chances of survival for people with serious injuries, and allowing the advanced surgeries that are performed today. Baekeland's photographic paper allowed people to pursue photography as a hobby, and allowed George Eastman to offer better film. Baekeland's first synthetic material from the Age of Plastics improved insulators used in the electrical industry. The large variety of phenols are likely to continue shaping our way of life. 

Silk and Nylon

Silk and Nylon

     Silk has always been regarded as a fabric for the wealthy, and it is considered irreplaceable. The desirable properties of silk- its warmth in cold weather and coolness in warm weather, its ability to take dyes so well, its smooth feel, and its luster- are all results of its chemical structure. The chemical structure of silk ultimately led to new trade routes between the East and the rest of the world.

     There is a legend that around 2640 B.C., Princess Hsi-ling-shih found that a thread of silk could be unwound from an insect cocoon that fell into her tea. It is unknown whether this story is true, however silk production did begin in China with the cultivation of the silkworm. The silkworm is a small gray worm that only feeds on the leaves of mulberry trees. The silkworm moth can lay approximately 500 eggs in a five-day period, and then it dies. A single gram of these eggs can produce over a thousand silkworms, which together produce around 200 grams of raw silk. The worm spends several days spinning its cocoon with a long, continuous strand of silk that comes from its jaw. It creates a dense cocoon, and gradually changes into a chrysalis. To extract the silk, the cocoon is heated to kill the chrysalis inside, and then submerged in boiling water to dissolve the secretion that holds the threads together. The silk is unwound from the cocoon and wound onto reels, with a thread length ranging from 400 to over 3,000 yards. 

      Although trade routes known as the Silk Road were opened throughout central Asia, China kept silk production details secret. Silk trade had a slow spread, but regular shipments were arriving in the West by 1 B.C.. The Chinese desperately wanted to maintain their silk monopoly, so they created new laws. Any attempt to smuggle silkworms, silkworm eggs, or white mulberry seeds out of China was punishable by death. According to legend, in the year 522, two monks managed to smuggle silkworm eggs and mulberry seeds in hollowed-out canes, opening silk production to the West. By the 14th century, silk production became a major industry in Italy, which became one of the financial bases of the Renaissance movement. There were various attempts to produce silk in North America, but they were commercially unsuccessful. However, the United States became one of the largest silk manufacturers in the world in the 20th century.
     Silk is a protein, which is made of amino acids. The three main amino acids found in silk are glycine, alanine, and serine, which have the smallest side groups of all the amino acids. Together, these amino acids consitute 85% of silk's structure. The very small side groups of these amino acids contribute to the smooth texture of silk. Silk is a polymer in which the constituent amino acids have varying side groups. Amino acids are linked by peptide bonds between the carbon of one amino acid and the nitrogen of the other amino acid. An estimated 80-85% of the amino acids in silk form a repeating pattern of glycine-serine-glycine-alanine-glycine-alanine. A pleated sheet structure formed by adjacent chains of amino acids accounts for the smoothness as well as the luster of silk. The amino acids that are not part of the pleated sheet structure are responsible for the brightness or "sparkle" of silk and its ability to easily absorb dyes.

     Silk is difficult to replicate due to all of its properties, however many attempts to produce a synthetic version were made beginning in the late 19th century. Although silk is a fairly simple molecule, it is chemically challenging to attach the amino acids in the combinations that occur in natural silk. In the late 1870s, while pursuing photography, French count Hilaire de Chardonnet found that spilled collodion (nitrocellulose material that coats photographic plates) stuck to a sticky mass. Chardonnet was able to pull long, silk-like threads from this mass. He had spent a lot of time studying the silkworm and the way it spins its silk fiber. Chardonnet tried forcing collodion through tiny holes, producing the first reasonable facsimile of silk fiber.
     Although the words synthetic and artificial are often used interchangeably, they have different meanings. Synthetic means that a product is man-made through chemical reactions. Artificial means that a compound has a different chemical structure than another compound, but it has properties that can mimic its role. Chardonnet actually produced artificial silk, even though it was synthetically made. This Chardonnet silk was soft and had luster, but it was also highly flammable. This silk was spun from nitocellulose, which is explosive. Chardonnet began manufacturing this material in 1891, but its flammable nature led to its downfall. Several incidents with the fabric caused the Chardonnet factory to be shut down. However, Chardonnet continued his production of artificial silk with a denitrating agent that made the fabric safer and only about as flammable as cotton. In 1901, Charles Cross and Edward Bevan produced viscose. The name was derived from the high viscosity of the substance. Viscose liquid forced through a spinnerette and into an acid bath produced viscose silk. This process was used by the American Viscose Company and the Du Pont Fibersilk Company (later becoming the Du Pont Corporation). By 1938, approximately 300 million pounds of viscose silk were produced each year. The viscose process is still used today to produce rayons- artificial forms of silk with threads composed of cellulose.
     In 1938, an organic chemist hired by the Du Pont Fibersilk Company created nylon, which was not cellulose based. In the 1920s, Wallace Carothers, an organic chemist from Harvard University who was 31 years old, was given the opportunity to do an independent study for Du Pont on a virtually unlimited budget. Carothers made the decision to work with polymers. At the time, it was unclear what the structure of polymers actually was. One theory was that they were groups of molecules grouped together (colloids). Another theory, proposed by Hermann Staudinger, was that polymers were very large molecules. Within a year of working, Carothers produced a polyester molecule that had an atomic weight larger than 5,000. He later increased the weight to 12,000, providing more support for the giant molecule theory. Staudinger won the Nobel Prize in chemistry for this theory in 1935.
     For four years, Carothers and his colleagues created different types of polymers and studied their properties, until they finally produced nylon. This fabric is man-made and is the most similar to silk in its properties, worthy of being called "artificial silk". Nylon is a polyamide, having the same amide linkages as silk. However, the monomer units are different. Rather than having an acid and amine on each end like silk does, nylon has units with either two acids or two amines. Nylon was used for the first time as toothbrush bristles in 1938. A year later (1939) nylon stockings were brought onto the market. It proved to be an excellent material for stockings because it did not sag or wrinkle, and it was far cheaper than silk. Only a year after being introduced, approximately 64 million pairs of "nylons" were sold.

                         

     Nylon's properties allowed it to find uses in other products, including fishing nets and lines, surgical sutures, strings for tennis and badminton rackets, and coating for electrical wires. During World War II, Du Pont shifted its focus to military-related products. Main uses of nylon became tire cords, mosquito netting, ropes, weather balloons, and parachute shrouds. After the war, civilian products were made again. In the 1950s, silk was commonly used for skiwear, clothing, sails, furnishings, and carpets. Nylon was also able to be molded and known as the "engineering plastic" because it was strong enough to be a replacement for metal. In 1953, over 10 million pounds of nylon were produced for that single purpose. Wallace Carothers became depressed and committed suicide in 1937. He swallowed a vile of cyanide, and never lived to see the success of his polymer.