Friday, March 20, 2020

Purify Alcohol or Denatured Ethanol Using Distillation

Purify Alcohol or Denatured Ethanol Using Distillation Denatured alcohol is toxic to drink and may be unsuitable for some lab experiments or other purposes. If you need pure ethanol (CH3CH2OH), you can purify denatured, contaminated or impure alcohol using distillation.   Alcohol Distillation Materials Balance100-mL volumetric flask or graduated cylinderDistillation apparatus250-mL beaker (or another container to receive the distilled alcohol)Hotplate or another flameless heat source (to avoid igniting the ethanol)Boiling chips200-mL impure ethanol (e.g., 70% denatured alcohol) You can also  make  a distillation apparatus if you dont already have one or arent sure what one looks like. Alcohol Distillation Procedure Put on appropriate safety gear, including goggles, gloves and protective clothing.Weigh the volumetric flask or graduated cylinder and record the value. This will help you determine your yield if you care to calculate it.Add 100.00 mL of alcohol to the volumetric flask. Weigh the flask plus alcohol and record the value. Now, if you subtract the mass of the flask from this value, you will know the mass of your alcohol. The density of your alcohol is the mass per volume, which is the mass of the alcohol (the number you just obtained) divided by the volume (100.00 mL). You now know the density of the alcohol in g/mL.Pour the ethanol into the distillation vessel and add the remaining alcohol.Add a boiling chip or two to the flask.Assemble the distillation apparatus. The 250-mL beaker is your receiving vessel.Turn on the hotplate and heat the ethanol to a gentle boil. If you have a thermometer in the distillation apparatus, youll see the temperature climb and then stabilize when it reache s the temperature of the ethanol-water vapor. Once you reach it, do not allow the temperature to exceed the stable value. If the temperature starts to climb again, it means the ethanol is gone from the distillation vessel. At this point, you could add more of the impure alcohol, if it didnt all fit in the container at the start. Continue distillation until you have collected at least 100 mL in the receiving beaker.Allow the distillate (liquid you collected) to cool to room temperature.Transfer 100.00 mL of this liquid into the volumetric flask, weigh the flask plus alcohol, subtract the weight of the flask (from earlier), and record the mass of the alcohol. Divide the mass of the alcohol by 100 to get the density of your distillate in g/mL. You can compare this value against a table of values to estimate the purity of your alcohol. The density of pure ethanol around room temperature is 0.789 g/mL.If you want, you can run this liquid through another distillation to increase its purity. Keep in mind, some alcohol is lost during every distillation, so youll have a lower yield with the second distillation and even less final product if you do a third distillation. If you double or triple distill your alcohol, you can determine its density and estimate its purity using the same method outlined for the first disti llation. Notes About Alcohol Ethanol is sold in the pharmacy sections of stores as a disinfectant. It may be called ethyl alcohol, ethanol or ethyl rubbing alcohol. Another common type of alcohol used for rubbing alcohol is isopropyl alcohol or isopropanol. These alcohols have different properties (notably, isopropyl alcohol is toxic), so if it matters which one you need, be sure the desired alcohol is listed on the label. Hand sanitizer gels also often use ethanol and/or isopropanol. The label should list which type of alcohol is used under the active ingredients. Notes About Purity Distilling denatured alcohol will remove enough impurities for may lab applications. Further purification steps could include passing the alcohol over activated carbon. This would be especially helpful if the point of the distillation is to obtain drinkable ethanol. Be very careful distilling ethanol to drink using denatured alcohol as a source. If the denaturing agent was simply an additive intended to make the alcohol bitter, this purification might be fine, but if toxic substances were added to the alcohol, a lesser degree of contamination may remain in the distilled product. This is especially likely if the contaminant had a boiling point close to that of the ethanol. You can reduce contamination by discarding the first bit of ethanol that is collected and the last portion. It also helps to tightly control the temperature of the distillation. Just be aware: distilled alcohol is not suddenly pure! Even commercially produced ethanol still contains traces of other chemicals.

Wednesday, March 4, 2020

Botswana †From Ancient Times to Current Democracy

Botswana – From Ancient Times to Current Democracy The Republic of Botswana in southern Africa was once a British protectorate but now is an independent country with a stable democracy. It is also an economic success story, rising from its status as one of the poorest countries of the world to the middle-income level, with sound financial institutions and plans to reinvest its natural resource income. Botswana  is a landlocked country dominated by the Kalahari Desert and flatlands, rich in diamonds and other minerals. Early History and People Botswana has been inhabited by humans since the dawn of modern humans about 100,000 years ago. The San and Khoi peoples were the original inhabitants of this area and South Africa. They lived as hunter-gatherers and spoke Khoisan languages, noted for their click consonants. Migrations of People into Botswana The Great Zimbabwe empire extended into eastern Botswana a thousand years ago, and more groups migrated into the Transvaal. The areas major ethnic group is the Batswana who were herders and farmers living in tribal groups. There were larger migrations into Botswana of these people from South Africa during the Zulu wars of the early 1800s. The group traded ivory and skins with the Europeans in exchange for guns and were Christianized by missionaries. British Establish the Bechuanaland Protectorate Dutch Boer settlers entered Botswana from the Transvaal, sparking hostilities with the Batswana. The leaders of the Batswana sought assistance from the British. As a result, the Bechuanaland Protectorate was established on March 31, 1885, including modern Botswana and parts of present-day South Africa. Pressure to Join the Union of South Africa The inhabitants of the protectorate did not want to be included in the proposed Union of South Africa when it was formed in 1910. They were successful in staving it off, but South Africa continued to pressure the UK to incorporate Bechuanaland, Basutoland, and Swaziland into South Africa. Separate advisory councils of Africans and Europeans were established in the protectorate and the tribal rule and powers were further developed and regularized. Meanwhile, South Africa elected a nationalist government and established apartheid. A European-African advisory council was formed in 1951, and a consultative legislative council was established by a  constitution in 1961. In that year, South Africa withdrew from the British Commonwealth. Botswana Independence and Democratic Stability Independence was secured peacefully by Botswana in June  1964. They established a constitution in 1965 and held general elections to finalize independence in 1966. The first president was Seretse Khama, who was the grandson of King Khama III of the Bamangwato people and a prominent figure in the movement for independence. He was trained in law in Britain and married to a white British woman. He served three terms and died in office in 1980. His vice president, Ketumile Masire, likewise was reelected several times, followed by Festus Mogae and then Khamas son, Ian Khama. Botswana continues to have a stable democracy. Challenges for the Future Botswana is home to the worlds largest diamond mine and its leaders are wary of over-dependence on a single industry. Their economic growth has raised them into the middle-income bracket, although there is still high unemployment and socioeconomic stratification. A significant challenge is the HIV/AIDS epidemic, with a prevalence estimated at over 20 percent in adults, the third highest in the world.​Source: US Department of State Background Notes