Alcohols

What are alcohols actually?

Alcohol is one of the most vital and common organic compound. It is a derivative of hydrocarbons with a hydroxyl functional group (OH^-) attached to a carbon atom of an alkyl or substituted alkyl. The hydroxyl group helps differentiate alcohol from other hydrocarbons as it contributes to physical properties of alcohol.

Alcohols are classified as primary, secondary and tertiary based on where the hydroxyl group is placed in the molecule. These groups vary in their chemical differences. Primary (1°) alcohols have a carbon with the hydroxyl group attached to only one alkyl group. Secondary (2°) alcohols on the hand, have a carbon with the hydroxyl group attached to two alkyl groups whereas tertiary (3°) alcohol have a carbon with the hydroxyl group attached to three alkyl groups.

Physical Properties of Alcohol

Solubility

Alcohols are soluble because the hydroxyl group in alcohol can engage in hydrogen bonding with the water molecules. However, the solubility of alcohols in water decreases as the length of the hydrocarbon chain increases. Long chain hydrocarbons, usually containing four or more carbons behaves more like an alkane and tends to form to form two immiscible layer.

Boiling Point 

Alcohols have hydrogen bonds as their intermolecular forces, whereas other hydrocarbons besides alcohol have Van der Waals forces as their intermolecular forces. Hence, alcohols have a higher boiling point than the other hydrocarbons. The boiling point of alcohol increases as the length of the hydrocarbon chain increases.

Flammability

As the mass of the molecule increases, the flammability of the alcohol decreases. During the combustion process, the number of covalent bonds to be broken in order for the alcohol to burn is greater as the molecular mass and size of the alcohol increases. Hence more energy is required to break those bonds, thus decreasing the flammability of alcohols as the molecular mass and size increases.

Alcohols and Its Uses

Each type of alcohol has a different IUPAC name. The most common and simplest ones are methanol, ethanol, propanol and butanol.

Methanol

It is also known as methyl alcohol and wood alcohol, has the chemical formula CH₃OH. Methanol is a versatile compound and is very often a key component in our daily products. Methanol is usually converted into formaldehyde, acetic acids and olefin in order to form a product. Among the materials made from methanol include paint thinner, synthetic fibres, plastics, solvents, adhesives, gel chafing fuel and many more. The most common use of methanol is as methanol fuels which is used in transportation. This is due to the fact that methanol burns cleanly, producing only water and carbon dioxide, hence resulting in an efficient combustion. Apart from that, it is widely available around the world, easily distributed and also inexpensive.

However, methanol is toxic and long-term contact with it may cause several health complications. Methanol poisoning is said to be the major cause of Parkinson’s disease, which is a kind of motor impairment that restricts the movement of muscles. Methanol toxicity can even cause vision loss. Methanol is also extremely flammable and may explode when exposed to open flames.  

Ethanol
It is also called ethyl alcohol and has a chemical formula of C₂H₅OH. Ethanol is one of the most commonly used alcohol and act as the building block in production of several daily products. Ethanol are said to be a renewable fuel and can be produced from renewable sources like sugar cane. Ethanol is can be produced by fermentation, therefore making it very useful for countries without an oil industry and helps reduce their dependency on imported petrol. Ethanol is widely used in making alcoholic beverages like wine and beer. Due to its high solubility, it is often used as solvents in making perfumes, toiletries, medicines. Ethanol is added to perfumes in order to stop the plant and animal extracts from going off. Ethanol is also used to produce methylated spirit. Methylated spirit is ethanol with small amounts of methanol, which is poisonous, and therefore inedible. Methylated spirit is used in lamps, stoves, to remove ink from non-porous surfaces and as components in household products.

There are several disadvantages of ethanol, mostly involving alcoholic beverages. Drinking a lot of alcohol in one session, just enough to get drunk results in short term problems. These problems include, having a hangover, becoming violent or aggressive, drunk driving which can lead to accidents, high alcohol intoxication in the body, resorting to drugs and regretted one night-stands. Heavy drinking on the hand can be more severe and may cause alcohol addiction, nutrition deficiency, liver failure, cancer, heart diseases, mental illness and many more. 

Conclusion

Hence, alcohol has its pros and cons. Alcohol does not only refer to alcoholic beverages but consists of several useful daily products. Examples of them would be the fuel for our cars and also the perfumes that with use. As for the alcoholic beverages, a controlled consumption would not do you much harm. 

“Emmm ~~ that smells good!”

Organic chemistry, the chemistry of carbon-containing compounds plays a huge role in our daily live as well as in the perfume manufacturing industries.

The most common organic compound for creating the lovely fragrance in perfumes is ester.

Ester is most widely used not only because it produces the pleasant aroma of fruits but also its high volatility because of the weak forces of attraction between the particles of the substance which are overcome easily, thus it evaporates easily from liquid to gas. Meaning that it can reach the olfactory system in the upper part of the nose. Then, it attaches to the receptors which transmits an impulse from the nose to the brain via neuron.

Esters

Esters occur naturally, but can be made in the laboratory by reacting an alcohol with an organic acid also known as carboxylic acid. A little sulfuric acid is needed as a catalyst to carry out the reaction. This is the general word equation for the reaction:

alcohol + organic acid    →    ester + water

For example:

methanol + butanoic acid    →    methyl butanoate + water

The diagram shows how this happens, and where the water comes from:

Unsaturated esters have a stronger scent compared to saturated esters because the higher the molecular weight, the weaker the odor they carry. Thus, unsaturated ester containing perfume are most highly preferred by manufacturers when in making of new creation of scents.

What esters smell like

Different esters have different smells. These are some examples:

alcohol	organic acid	ester made	smell of ester
pentanol	ethanoic acid	pentyl ethanoate	pears
octanol	ethanoic acid	octyl ethanoate	bananas
pentanol	butanoic acid	pentyl butanoate	strawberries
methanol	butanoic acid	methyl butanoate	pineapples

Stabilizers and Perfume Bases

All perfumes are composed of both a base and a fragrance compound. The perfume compound will account for 20 to 50 percent of the fragrance and is made from essential oils and synthetic fragrances like from ester. Perfume bases, which account for 50 to 80 percent of a fragrance, are generally made from liquids such as alcohol and water. They also include a variety of stabilizers, which are used to fix a perfume's scent and ensure that ingredients do not separate. Common perfume base is ethyl alcohol and for stabilizers is benzyl benzoate.

Most oil-based perfumes are free of stabilizers. The oils used for these bases are clearly identified and will be familiar to perfume wearers. These fragrances must be applied with the fingertips or with a roller ball and are not available in spray-on form.

Ethyl Alcohol

The majority of perfumes manufactured from industries contain an ethyl alcohol base which is also known as ethanol. Also known as ethanol or pure alcohol, ethyl alcohol vaporizes quickly. It is used in perfume precisely because it acts as a carrier for a perfume compound but dissolves quickly on the skin. Some organic perfumes use a denatured alcohol in place of ethyl alcohol due to concerns about the safety of ethanol-based products.

Benzyl Benzoate

Benzyl benzoate is made from the combination of benzoic acid and benzyl alcohol, is used as a fixative or stabilizer in many perfumes. This compound is often found in plants and naturally processed essential oils. When added to perfumes, it allows for the stability of fragrance ingredients. Benzyl benzoate helps perfumes to have a consistent scent and can prevent variation in scent profiles for several years.

Benzyl Benzoate is a natural component of cinnamon essential oil. It composes about 3% of the oil. Cinnamon essential oil has therapeutic benefit and when used in small amounts is safe.

Generally the amounts of essential oils used in cosmetics and personal care products is so small that you don't have to be concerned with any precautions associated with the essential oil. The synthetic version, on the other hand is the chemical used to kill head lice and is associated with a variety of adverse effects, including burning and itching of the skin, formation of blisters, reddening, crusting or scaling of the skin, jerking movements, difficulty urinating or sudden loss of consciousness. Thus, try to avoid products with benzyl benzoate listed as an ingredient, if it does not specify that it is from cinnamon essential oil.

Essential Oils
Essential oils are used to add scent to many perfumes. Many of these oils have been sourced from plants, woods, herbs, spices, and other organic materials. However, there are many synthetic essential oils available on the market. Common oils used in the industries are lavender oil, jasmine oil, opium oil and more.

Ethers are much stronger than esters but both have similar properties. They are a powerful antispasmodic, antibacterial, and anti-inflammatory. They are very gentle on the skin and particularly efficient in relaxing and rebalancing the nervous system. Examples of ethers and esters include cinnamyl acetate which are found in cinnamon, and myrtinyl acetate found in myrtle.

Conclusion

There are many esters or chemical elements used in making a bottle of perfume such as benzyl acetate, diethyl phthalate and so on. Some but not all synthetic perfumes are safe for use as some chemical containing perfumes such as the benzyl benzoate have some negative effects on health. So when choosing for a good and safe bottle of perfume, always check the ingredients listed behind the bottle to avoid the danger. Like how many always say, “Better safe than sorry.”

Benzoic acid – Its Uses And Harms

Benzoic acid, C₆H₅COOH, is a colourless organic compound. It is classified as the simplest aromatic carboxylic acid. The name derived from gum benzoin. It is weakly acidic, with a pH of 2.8. In normal conditions it has a white, flaky appearance that actually consists of small, needle-like crystals.This weak acid and its salts are used as a food preservative. Benzoic acid is an important precursor for the synthesis of many other organic substances.

History

Benzoic acid was discovered in the 16th century. The dry distillation of gum benzoin was first described by Nostradamus (1556), and subsequently by Alexius Pedemontanus (1560) and Blaise de Vigenère (1596).
Justus von Liebig and Friendrich Wohler determined the structure of benzoic acid in 1832. They also investigated how hippuric acid is related to benzoic acid. 
In 1875 Salkowski discovered the antifungal abilities of benzoic acid, which were used for a long time in the preservation of benzoate containing fruits.

Industrial preparations

Benzoic acid is produced commercially by partial oxidation of toluene with oxygen.  The process is catalyzed by cobalt or manganese naphthenates. The process uses cheap raw materials, proceeds in high yield, and is considered environmentally attractive.


Uses of Benzoic Acid

Food preservative

Benzoic acid and its salts are used as a food preservative, Benzoic acid inhibits the growth of mold, yeast and some bacteria, a major causes of food spoilage. It  is either added directly or it is created from reactions with its sodium, potassium or calcium salt. The mechanism starts with the absorption of benzoic acid in to the cell. If the intracellular pH changes to 5 or lower the anaerobic fermentation of glucose through phosphofructokinase is decreased by 95 percent. The effectivity of benzoic acid and benzoate is thus dependent on the pH of the food. Acidic food and beverage like fruit juice (citric acid) , sparkling drinks (carbon dioxide) , soft drinks (phophorus acid), pickles vinegar or other acidified food are preserved with benzoic acid and benzoates.

Medicinal Uses

Benzoic acid is a constituent of Whitfield Ointment which is used for the treatment of fungal skin diseases such as tinea, ringworm and athlete's foot. It is also considered an effective treatment for acne. Benzoic acid was used as an expectorant, analgesic and antiseptic in the early 20th century.


Cosmetic Products and Pharmaceutical Products

Many toothpastes and mouthwashes also contain benzoic acid, as well as a diaper cream. Some of the perfumes is added with benzoic acid too.

Synthesis Of Other Chemicals
Benzoic acid is used to make a large number of chemicals, important examples:

• Benzoyl chloride, C₆H₅C(O)Cl, is obtained by treatment of benzoic with thionyl chloride, phosgene or one of the chlorides of phosphorus. C₆H₅C(O)Cl is an important starting material for several benzoic acid derivates like benzyl benzoate, which is used as artificial flavours and insect repellents.
• Benzoyl peroxide, [C₆H₅C(O)O]₂, is obtained by treatment with peroxide. The peroxide is a radical starter in polymerization reactions and also a component in cosmetic products.
• Benzoate plasticizers, such as the glycol-, diethylengylcol-, and triethyleneglycol esters are obtained by transesterification of methyl benzoate with the corresponding diol. Alternatively these species arise by treatment of benzoylchloride with the diol. These plasticizers are used similarly to those derived from terephthalic acid ester.
• Phenol, C₆H₅OH, is obtained by oxidative decarboxylation at 300-400°C. The temperature required can be lowered to 200°C by the addition of catalytic amounts of copper(II) salt. The phenol can be converted to cyclohexanol, which is than starting material for nylon synthesis.

Harms Of Benzoic Acid

If Benzoic Acid is inhaled, it can cause damage to the nervous system. Eaten in food, it’s mildly toxic. Benzoic Acid has been linked to asthma problems and increased levels of hyperactivity in children. That is why children nowadays are very hyperactive, causing a lot of troubles in school.

There is some concern that benzoates added to some types of soft drinks might produce benzene, a dangerous carcinogen and environmental pollutant. Scientists believed that benzene is one of the substances that cause cancer in human. Benzene exposure typically comes from breathing exhaust fumes, but it can also be produced from the interaction of benzoic acid and ascorbic acid, a precursor of vitamin C. The pH of the beverage, the temperature at which it is stored and the extent of exposure to UV light could all affect the extent to which benzene is produced.


Considerations
Because benzoic acid is toxic, the amount of benzoates that can be added to foods is carefully controlled. Codex Alimentarius, an international treaty dictating food safety standards, limits the amount of benzoic acid or sodium benzoate to 0.05 to 0.1 percent by volume. Most foods are allowed no more than 1,000 mg per kilogram. Liquid egg products, diet foods, chewing gum and processed vegetables are among the foods with the highest amount of benzoate legally allowed.

Benzoic acid has been deemed safe to use in small quantities, but is very harmful and should be avoided in large quantities. If you must work with benzoic acid, wear appropriate safety gear and follow recommended cleanup and containment procedures. Avoid prolonged exposure. It would be wise to limit use of products or foods containing benzoic acid to limit the chances of toxic build-up within the body.



Conclusion

Benzoic acid is a carboxylic acid organic compound which provide many usage to the human. Benzoic acid can acts as a food preservative, cosmetic products, pharmaceutical products and also important in medical uses. Despite of having a lot of advantages, benzoic acid also causes harms to human. First of all, benzoic acid is believe to cause hyperactive in children. Benzoic acid can reacts with other products, producing benzene, which is a cancer causing substances. In fact, benzoic acid is not suitable for human who have asthma. Since benzoic acid brings a lot of usages and also harms to us, we must be careful in using benzoic acid. For example, we should prevent the overdose of benzoic acid, avoid prolonged exposure to benzoic acid and also try to prevent the using of benzoic acid whenever is necessary. Thank you.