Uses of organic chemistry in daily life:: Biofuel

Biofuels are fuels largely derived from living organisms that use the sun as their main energy input. Energy may be put into planting, fertilizing, harvesting, and processing the crops, but most of the energy, in the final plant product, comes from the sun. Plants convert solar energy into chemical forms of energy (carbohydrates, fats, etc.)through the process of photosynthesis. Plant convert the solar energy into a chemical form more usable as a fuel. 

                        

Biofuels are considered carbon neutral. That is, they release no net amount of carbon dioxide into the atmosphere.This because the carbon dioxide that is released during combustion was originally absorbed from the atmosphere during the process of photosynthesis.Hence, no extra CO2 is pumped into the atmosphere The process of photosynthesis can be summarised by the equation below:

6H2O + 6CO2  ---> C6H12O6 + 6O2

Production of biodiesel::

                         

The biofuel can be produce using palm oil .The process used to produce biodiesel is known as transesterification. Transesterification is the process of exchanging the alkyl group of an ester with another alkyl group, from a different alcohol. Vegetable oil contains fatty acids bonded to glycerol to form triglycerides. In the case of biodiesel, a vegetable oil ester is combined with a simple alcohol, methanol, and a catalyst, resulting in the breakup of the triglyceride ester to form glycerol and three methyl esters (biodiesel) The molecule of biodiesel is a long chain of carbon atoms, with hydrogen atoms attached, and at one end is the ester functional group .

Making good biodiesel requires several other steps besides the transesterification reaction(as shown below). First, traces of water in the vegetable oil have to be removed.  This is to prevent the water from react with the vegetable oil in the reaction and make soap.

The filtered waste vegetables oil:

If soap gets made, it will complicates the steps after the transesterication reaction that are needed to separate the biodiesel from leftover methanol, the NaOH or KOH catalyst, and the glycerol byproduct. Diesel engines can burn biodiesel fuel with no modifications (except for replacing some rubber tubing that may soften with biodiesel).  This is possible because biodiesel is chemically very similar to regular diesel, shown below.  Notice that regular diesel also has the long chain of carbon and hydrogen atoms, but doesn’t have the ester group.Actually, the first diesel engines didn’t run on “diesel” fuel, but on vegetable oil, a sample molecule of which is shown below.  Notice that it also has the long rows of carbon and hydrogen atoms, but is about three times larger than normal diesel molecules.  It also has ester functional groups , like biodiesel.That larger size of vegetable oil means that in cold weather it gels, making it hard to use in an engine.  Converting it into biodiesel makes it a smaller molecule, closer to the size of regular diesel, so that it has to get colder than vegetable oil before it starts to gel.

The advantages of biofuel::
1.Reduce the greenhouse gases
No matter is the melting of the frozen glaciers that shroud Kilimanjaro, Africa's highest mountain, or the overall rise in the level of the oceans, global warming getting seriously nowadays.Most of the scientists agree that fossil fuels, such as oil and coal, drive the temperature increase. When burned, fossil fuels release greenhouse gases, including carbon dioxide, into the atmosphere. These greenhouse gases trap radiation from the sun close to the surface of the planet, causing the planet to warm.

To stem the release of greenhouse gas, people around the world are using biofuels, such as ethanol or biodiesel, to power their homes, cars and factories. According to the Nebraska Ethanol Boar, some experts say that ethanol reduces greenhouse gas emissions up to 65 percent. Scientists in Australia say biodiesel made from cooking oil reduces greenhouse gas emissions by 87 percent compared with petroleum diesel. Still, many people believe that growing and turning some energy crops -- especially corn -- into fuel, uses a huge amount of fossil fuel, contributing to the release of heat-trapping gases.

2.Sustainibility

One day the world will run out of fossil fuels, and with it, our main sources of energy will go up in smoke. But biofuels are different. They're made from plants that can grow and be replanted again and again. Perennial crops don't even have to be replanted. Still, not all biofuels are created equal. Some "energy crops" produce more energy than others. For example, rapeseed has a higher oil content than other vegetable plants, which means rapeseed can generate more energy when burned. Perennial plants, such as switchgrass, provide an abundant source of power, generating five times as much energy as they take to grow.

3.High quality engine performance
The neat thing about biodiesel is that it can run in existing diesel engines with little or no modification to the engine or its fuel system. Performance is the same. However, some biodiesel vehicles are sluggish in cold climates. Since most vegetable oil is high in saturated fat, ice crystals tend to form in the biodiesel causing a vehicle's engine to struggle. However, biodiesel made from certain types of vegetable oil, such as canola (a form of rapeseed), is lower in saturated fat, which makes it harder for ice to form in frigid temperatures. Biofuels help engines last longer, too. Oil has a high viscosity rate. Tests show that high biodiesel blends above B10 (10 percent biodiesel, 90 percent petroleum diesel) do not impact the vehicle's engine performance.

4.Biofuel refineries are cleaner

When oil comes out of the ground, it doesn't magically transform itself into gasoline or home heating oil. Oil refineries must convert crude oil into useable products. There are 153 of these refineries in the United States and more than 90 million people live within 30 miles (48.28 kilometers) of them. Yet each year, these refineries release millions of pounds of cancer-causing chemicals, including benzene, butadiene and formaldehyde into the environment. In addition, the refineries spew nickel, lead, sulfur dioxide, and other pollutants that can cause heart disease, asthma and other health problems.

For the most part, biofuel refineries, which turn feedstock sch as corn and soybean into biofuel, are more environmentally friendly. For example, ethanol plants fueled by natural gas emit very few pollutants, including greenhouse gases. However, coal-fired ethanol plants release copious amounts of carbon and other greenhouse gases -- not to mention a significant amount of particulate matter -- into the atmosphere. On the other hand, ethanol plants fueled by biomass and biogas produce less gas emissions and are cleaner to run.

5.Health benefits

 Biofuels discharge fewer toxins into the air than fossil fuels. When compared to conventional diesel, biodiesel reduces smog-forming particulate matter, which reduces cases of asthma and other respiratory illnesses. In addition, biodiesel doesn't emit any sulfur oxides and sulfates, which contribute to acid rain.For its part, ethanol generally burns better and more robustly than gasoline, generating less pollution.  When pollution is reuced, our health would be safe.

Disadvantages of biofuels::

1.Food Seurity

Biofuel production using food crops such as corn, soybeans and sorghum has the potential to alter drastically the world's access to affordable food. The simple supply-and-demand economics of biofuels -- increase demand for corn, for example, and corn becomes more expensive or the access to affordable nutritious food for the region's population.

The rise in demand for food-biofuel crops can have a positive effect for crop producers, in the form of higher prices for their produce. But that price quickly trickles down to consumers. A pig farmer, for example, may have to pay a few extra dollars per bushel to buy corn to feed his livestock. That directly translates into more expensive bacon and ham at the grocery store. For the billions of people who live on only a few dollars per day, even a small increase in food prices could put their access to proper nutrition at risk.

One way to counter this lies in simple diplomacy: The globalization of world commerce means that it's now easier than ever to move food supplies from one part of the world to another in response to increased demand. However, ready access to food imports, and the ease of exporting, hinge on a wide range of political and social factors. Relying on produce from halfway around the globe to feed a hungry nation is a risky price to pay for widespread biofuel integration into the world's energy supplies.

2.The use of fertilizer on the crops

This is a problem biofuel crops share with food crops, gardens and lawns worldwide. All of these plants grow better when given fertilizer. But those fertilizers can have harmful effects on the surrounding environment, and expanded biofuel production could mean a major pollution threat to sources of fresh water.

Many fertilizers contain nitrogen and phosphorus. While both of these additives promote rapid and hearty growth in many crops, they have a downside. Overuse or inappropriate application can leave excess fertilizer in the soil, which then washes through regional watersheds and into streams, rivers, lakes and underground aquifers. And once the chemicals are in the water supply, bad things can happen.