OMG !! IT SMELLS SO NICE !!

     Last week, my sister went to a birthday party of her friend. She always put perfume when she is going to somewhere. So out of curiosity, I checked the chemicals components inside a perfume and how it was made. And this is what I gained so far. But the precise formulae of the commercial perfumes are kept secret. The definition of perfume is a fragrant liquid typically made from essential oils extracted from flowers and spices, used to impart a pleasant smell to one's body or clothes. Perfume contains aldehydes group, the functional group consists of a carbon atom bonded to a hydrogen atom with a single covalent bond and an oxygen atom with a double bond. The general formula of an aldehyde is R-CH=O.   

Aldehydes is vary in smell, for example, formaldehyde and acetaldehyde have sharp and unpleasant odours. But the common aldehydes used in perfumes is benzaldehyde and furfural, which have pleasant and flowery odours, they are usually found in the essential oils of certain plants. Some aldehydes have a very pleasant odours, and they can be detected in a very low level of concentration. Floral aldehydes gives the impression of the flowers like lavender, rose and jasmine. Because of these characteristics, the aldehydes are used in the production of many perfumes. Production of perfumes contain four main steps, which are Collecting, Extraction, Blending, and Aging. Esters can be also found in perfume. They are the products of the esterification reaction occuring between acids and alcohol. Water is produced as a second product. When the molecular weight of small, they carry a higher odour. They are resposible for the pleasant smell of apples, bananas, strawberries. Saturated esters have a weaker odour than the unsaturated ones. 

Making of esters

     Alcohol + organic acid    →    ester + water 

They are 5 main property of perfume. First is they are non-toxic, so that they does not poison the wearer. Secondly, the must not irritate the skin, this is to prevent the wearer from suffering from rashes. Thirdly, they are very colatile, they evaporates easily. This is because the perfume can reach the nose easily. Next, they are insoluble in water, so that it is not washed away easily. Lastly, they does not react with water. This is to avoid the perfume reacting with sweat.

Authors : Aaron Leong Hee Lee, Huong Nai Zheng, Ong Kai Yin, Lim Huang Xu

Petroleum is very EXPENSIVE !!!

Have you ever wondering what is the composition of petroleum?

Applications of Chemistry In the Petroleum Industry

·        It comprises of alkanes, cycloalkanes, aromatic hydrocarbons, and complex chemicals like asphaltenes.

·        Each petroleum variety has a unique mix of molecules to determine its physical and chemical properties.

1)     alkane

  

    So, let’s talk about the alkanes in petroleum. As everyone know alkanes are saturated hydrocarbons with contain only carbon and hydrogen. Besides, they can existed in the form of branched or straight chain. So, the general formula for them are C_nH_2n+2. Besides, they can have 1 to 40 carbon atoms per molecule.

• ·       Pentane (C₅H₁₂) to octane (C₈H₁₈) are normally refined into gasoline. 
  
• ·       Nonane (C₉H₂₀) to hexadecane (C₁₆H₃₄) can be refined into diesel fuel, kerosene or jet fuel.
• ·       Alkanes that have more than 16 carbon atoms can refined into fuel oil and lubricating oil.
• ·       Paraffin wax is an alkane with approximately 25 carbon atoms and normally used in candles and in crayons. 
  
• ·       Those alkane with four or fewer carbon atoms are known as petroleum gases.

   

Do you know?

    The petroleum gases are sold as liquefied petroleum gas inside the gas tank after being pressurize. During the winter season, butane gas (C₄H₁₀), is blended into the gasoline pool. So, it is best known for powering cigarette lighters. Besides, it is also a main fuel source for many developing countries.

2)     Cycloalkanes

    Cycloalkanes is similar to alkane which contain only carbon-hydrogen bonds. But, the carbon atoms are joined up in the form of ring.

    The cycloalkanes in petroleum also known as naphthenes. So, they are saturated hydrocarbons with the formula C_nH_2n. Cycloalkanes have similar properties to alkanes but they have higher boiling points. The residue of the refinery process is known as asphalt.

1)     Aromatic hydrocarbons

    The aromatic hydrocarbons are unsaturated hydrocarbons with minimum one planar six-carbon rings also known as benzene rings. Therefore, the hydrogen atoms are attached with the formula C_nH_n. They are flammable and tend to burn with a sooty flame. Majority of them have a sweet aroma. However, some of them are carcinogenic and could cause lung cancer after inhaled.

Facts:

    All these different chemical molecules are separated by fractional distillation at the petroleum industry to produce gasoline, jet fuel, kerosene, and other hydrocarbons. For example, 2,2,4-trimethylpentane is widely used in gasoline. It has a chemical formula of C₈H₁₈ and reacts with oxygen exothermically. The reaction is shown below.

2 C₈H_18(l) + 25 O_2(g) → 16 CO_2(g) + 18 H₂O_(g)  (ΔH = −5.51 MJ/mol of octane)

  

     Besides, the different molecules in an oil sample can be examine in the laboratory. The molecules are separated in a gas chromatograph after extracted in a solvent. Finally, the scientists will determine with a suitable detector such as a flame ionization detector or a mass spectrometer.

    

    Furthermore, the incomplete combustion of petroleum or gasoline will produce toxic byproducts. When the combustion process is deprived of oxygen will results in the production of carbon monoxide. In addition, the combustion of gasoline would produce exhaust gases and given out from the car engine. The exhaust gases usually include nitrogen oxides which would lead to photochemical smog due to the high temperatures and high pressures involved.

Useful Links: 1) http://www.chemguide.co.uk/organicprops/alkanes/background.html

                        2) http://www.petroleum.co.uk/alkane-chemistry

                        3) http://www.shell.com/global/future-energy/natural-gas.html

                        4) https://www.khanacademy.org/science/organic-chemistry/bond-line-       structures-alkanes-cycloalkanes

                        5) http://www.eia.gov/energyexplained/index.cfm?page=oil_home

Authors : Aaron Leong Hee Lee, Huong Nai Zheng, Ong Kai Yin, Lim Huang Xu

I'M DRUNK..... ( just kidding ) XD

Process of Producing Alcoholic Beverages.

Alcoholic beverage is a drink that contains certain concentration of psychoactive drug ethanol. Alcoholic drinks are generally categorized with difference alcohol by volume into three major types, which are beers, wines and spirit.The first evidence of alcohol was existed in Neolithic period of northern China by chemistry research team with the chemical analysis of jars. Chemical analysis established that a fermented drink made of grapes,hawthorn berries ,honey and rice was being produced in 7000-6650 BC according to a investigate published in the Proceedings of the National Academy of Sciences. The existence of alcoholic beverages was founded dating from 3150 BC in ancient Egypt, 3000 BC in Babylon, 2000 BC in pre-Hispanic Mexico, and 1500 BC in Sudan. Alcoholic beverages existed in medical field since 2100 BC in Sumeria and Egypt for example alcoholic drinks were recommended for those who are suffering or those who are in critical condition to ease their pain. In addition, diluted wine was a part of classical Greece breakfast, and it was consumed in most of the Roman citizens in the first century. As state by the post-conquest Aztecdocument, drinking of the pulque also known as local “wine” was commonly restricted to religious ceremonies but was allowed to elders.

Fermented beverage

A chemical reaction that carbohydrate such as glucose turned into acidic food or alcoholic beverage. Grapes are compressed to excrete the juice that contain high concentration of sugar and then either moved rapidly away from the peel or left to rest for a certain time to soak up the flavour, tannins, and color of the protective layer for the production of wine. Final step, the extracted juice that added yeast is left to ferment for weeks.

Double fermentation

Secondary fermentation is commonly used in the production of wines, it means second period of fermentation in a container other than the one used in the previous fermentation process. For example, carboy is used for the first fermentation and the content is moved to a oak barrel for second fermentation stage.

Distilled beverage

Alcohol is most commonly known in beverages and is referred to generically as Alcohol, Common Alcohol or Grain Alcohol. For this last purpose, Ethanol also known as CH3CH2OH is produced by fermentation. Alcoholic beverages that have higher concentration of alcohol than 12 to 15% could not be produced by simple fermentation of sugar, because yeast fermentation could not undergo in high Alcohol concentration. Hence, distillation method was applied to create  higher concentration alcoholic beverages.

 Distillation from Wine

Distillation is the centuries-old process used to produce alcohol. Heat is used to separate the components of a liquid, or mash, and as vaporization takes place the vapors are cooled so they condense into neutral spirits with little colour, aroma, or flavour.



Authors : Aaron Leong Hee Lee, Huong Nai Zheng, Ong Kai Yin, Lim Huang Xu