Benzoic acid, also known as sodium benzoate or benzoic acid (E210), is a preservative. It is used in small amounts to prevent the growth of harmful bacteria. This prevents food from spoiling and becoming unsafe to eat.
Benzoic acid is a white, crystalline powder that occurs naturally in many fruits and vegetables. In fact, it is often used to prevent food from spoiling — especially items with a high water content such as strawberries or cranberries. It is also used in the pharmaceutical industry and elsewhere as an additive, preservative, antioxidant and flavoring agent.
What is benzoic acid in food?
Benzoic acid is an organic compound with the formula C7H5O2. It is a carboxylic acid, and its salts are known as benzoates.
Benzoic acid has a pleasant smell; it is one of the components of the odor of cloves. Benzoic acid is used for fruit preservation and to make certain types of food such as jams and jellies more acidic. It is also used in cosmetic products, such as perfumes and shampoos, because it prevents bacteria from growing in them.
Benzoic acid can be found naturally in some foods including cranberries, apples and berries. It can also be produced by fermentation processes using yeast or bacteria.
However, benzoic acid can also be made synthetically in large quantities through heating together formaldehyde, carbon monoxide, and benzene at high temperatures under pressure (in the presence of solid carbon dioxide).
What is benzoic acid used for?
Benzoic acid is an organic compound that has a wide range of uses. It is a white solid that is soluble in water, alcohol, and ether. It can be produced by the oxidation of benzene.
The most common use of benzoic acid is as a food preservative. Benzoic acid acts as a fungicide, bactericide, and antifungal agent. It prevents the growth of mold and yeast under certain conditions. It is also used in perfumes to give them their unique scents.
Benzoic acid can also be used as an ingredient in some toothpaste and mouthwashes due to its ability to kill bacteria in the mouth. In addition to this application, benzoic acid can also be used on the skin to help treat acne because it slows down the production of sebum by blocking pores on the skin’s surface.
Benzoic acid is also used as an expectorant for cough drops because it helps loosen phlegm from your lungs so you can cough it up easier.
How is benzoic acid made?
Two types of benzoic acid exist, the natural form extracted from plants and the flavoring form, FEMA 2131. One of the most commonly used is obtained from toluene synthesis, and in this section, we will discuss how it is made.
Toluene oxidation
Benzoic acid is largely produced commercially by oxidizing toluene with oxygen, with cobalt catalysts, in a liquid-phase process.
As crude benzoic acid may contain by-products such as benzaldehyde, benzyl alcohol, and benzyl benzoate, other manufacturing processes (e.g. sublimation, recrystallization, and neutralization) are needed to purify it.
Other methods
According to the FDA, benzoic acid can also be manufactured using the following two methods:
- Using zinc oxide to catalyze phthalic anhydride molten
- Benzotrichloride hydrolysis
HCL can also be used to produce benzoic acid from sodium benzoate.
Specification
| Other Names |
|
| CAS Number | 65-85-0 |
| Chemical formula | C7H6O2 or C6H5COOH |
| Molar Mass | 122.123 g·mol−1 |
| Boiling Point | 250 °C (482 °F; 523 K) |
| Melting Point | 122 °C (252 °F; 395 K) |
Properties
- An odorless white crystalline flake, needle, powder, or granular substance containing benzoin or benzaldehyde.
- It is slightly soluble in water, but readily soluble in ether, ethanol, dichloromethane, diethyl ether, and other organic solvents.
- It is a weak acid with an acid taste that can affect a food’s taste and PH.
benzoic acid structure
The structure consists of benzene and carboxylic acid. The functional group carboxyl and aromatic benzene rings make up this compound. These two functional groups can react with other chemicals to form many derivatives.
1. Carboxylic acid
It is easy for carboxylic acid to react with other groups, such as the reactions below:
- With sodium bicarbonate or sodium hydroxide, sodium benzoate can be produced.
- In artificial flavors, fragrances, and personal care products, esters like methyl, ethyl, butyl, and hexyl benzoate are formed by esterification with alcohols. Through the reaction of two molecules of benzoic acid to form benzoic acid anhydride.
- Benzoic acid amides are formed by the amide reaction with amino.
- Benzoyl chloride can be obtained by replacing the OH in carboxylic acid with chloride.
- Alcohol benzylated by reduction.
- Other uses include making benzaldehyde.
2. Aromatic benzene ring
The aromatic benzene ring can also react with other substances:
- Nitration produces m-nitrobenzoic acid.
- Salicylic acid is produced by hydroxylation. It is also possible to treat skin irritation and inflammation with benzoic and salicylic acids together.
PKa
Benzoic acid has a PKa of 4.2. The PKa value indicates an acid’s acidity, as weak acids partially dissociate in water and reach equilibrium.
How do you calculate benzoic acid’s PH?
As a weak acid, benzoic acid dissociates proton and benzoate ions after reacting with water.
dissociate equilibrium
Ka value
relationship between pka and ph
Here is the dissociation equation for benzoic acid and the relationship between PKa and PH. HA represents benzoic acid, A- represents the benzoate ion.
First, assume that total HA concentration is 0.001 mol/L.
Benzoic acid can be more soluble than 0.001 mol/L at 25°C. As an example, n=3.44/122.123 = 0.028mol/L would be the mol concentration since solubility/molecular formula equals n = n = 3.44/122.123 = 0.028mol/L. To make it easy, we are using 0.001 mol/L here.
Next, write the equilibrium equation for ionization:
HA(aq)+H2O(l)⇌A−(aq)+H3O+(aq)
- The concentration of Hydronium is [H3O+]
- [A−] represents the conjugate base concentration
- HA stands for benzoic acid concentration
In both cases, the concentration of [A−] and [H3O+] is same. In this case, we assume a concentration of X. HA will be 0.001 – X in the solution at the end.
In step 3, write X*X/0.001-X = Ka.
The X value for 0.001-X is similar to 0.001, so the PH value is 3.6.
Slightly polarity and Solubility
A non-polar benzene ring is attached to a smaller polar carboxylic acid group in benzoic acid. It is considered slightly polar because of its large hydrophobic benzene ring.
Solvents that are polar tend to dissolve polar compounds. That’s why benzoic acid is slightly soluble in water (polar) and dissolved in non-polar solvents such as ether and MTBE (Methyl tert-butyl ether).
Although ethanol is polar, benzoic acid can dissolve in it since both undergo esterification. Exceptions do exist here.
The solubility of benzoic acid in water or other solvents depends primarily on the polarity of the solvent, the solution temperature, and other solutions, such as NaOH or HCl.
Here are the details.
1. Water solubility
The solubility of benzoic acid is 3.44 g/L at 25 °C, since it is a weak acid that only partially dissociates in water. As the high temperature promotes the dissociation to its conjugate base benzoate ion, it dissolves in hot water, with a solubility of 56.31 g/L.
2. Solubility in NaOH
NaOH is soluble in benzoic acid. NaOH is a strong base, and it reacts with the dissociated proton from benzoic acid to promote its dissociation.
This is how NaOH affects water solubility.
In alkaline conditions, benzoic acid dissociates completely and forms sodium benzoate, but it loses its preservation properties.
3. Solubility in HCl
An acidic medium, such as HCl, makes benzoic acid more insoluble. With the increase of H+ ions, the equilibrium of dissociation will move to the left, making it more insoluble than water.
HA(aq)+H2O(l)⇌A−(aq)+H3O+(aq)
What is the main application of benzoic acid?
In addition to being used in foods and beverages, benzoic acid can also be added to cosmetics and pharmaceuticals to preserve them. However, its main application is in the synthesis of organic chemicals for a variety of industries, such as perfumes, plastics, dyes, etc.
Benzoic acid was used in the following percentages and uses 30 years ago, according to JECFA:
- For the manufacture of phenol, 60% was used
- The caprolactam content in nylon fibers is 30%
- The production of sodium, potassium, and calcium benzoates requires 5%
- In the case of benzoyl chloride, it is 3%
- For alkyd resins, benzoate esters, etc., 2%
At present, benzoic acid is also used in feed additives and as an intermediate in pharmaceuticals and plastics.
Here are some of its different uses.
Food
Food-grade benzoic acid inhibits the growth of microorganisms in acidic foods. It is mostly active against yeasts, molds, and bacteria. A pH range of 2.5 to 4.0 would be optimal for its antimicrobial activity.
In the laboratory
benzoic acid is used as a mild oxidizing agent. It can be used to prepare other chemicals too, like sodium benzoate or bromobenzene. In industry, it is used to make certain drugs like aspirin and acetaminophen.
Chemical Production
It can be used to make phenol, which is used to make certain dyes and synthetic detergents; bisphenol A (BPA), which is used in the production of epoxy resins; 1,2-dihydroxybenzene, an intermediate in the production of other chemicals such as carbamates, sulfonamides, and ureas; and benzaldehyde, which is used as a flavoring agent.
Cosmetics
In cosmetics and personal care products, benzoic acid can be used to bulk up, mask, and preserve.
- Products for skin care: facial moisturizer, sunscreen
- Brushing your teeth
Industrial Intermediates
Industrial uses are closely related to aromatic rings or carboxyl groups. Carboxylic acid is commonly used for the production of phenol, plastics, and benzyl benzoate.
Others
Benzoic acid is used in cosmetics, such as perfumes, because of its pleasant odor. It is also a common food preservative added to jams, jellies, and syrups. In addition to being used as a food additive, benzoic acid can also be found in toothpaste and mouthwash products as well as some cough medicines.
In food, why is benzoic acid less common?
However, its use in food and beverages is not as common as sodium benzoate and potassium benzoate, due to three main issues (especially the solubility):
- Water solubility: slightly soluble, not easy to use
- Acidity: It affects the pH of food and drinks
- Its solution has an acid taste, which will affect the taste of food
Because of this, it is always prepared in its salt form – sodium benzoate, even though the antimicrobial property comes from benzoic acid.
The typical level of benzoic acid and sodium benzoate in food is between 0.05 and 0.1%.
It may be found in the following foods:
- Fruit juice
- Pickles
- Jams
- Sparkling drinks
- Soda
Is benzoic acid safe?
Benzoic acid is a naturally occurring chemical that is used as a preservative in many food and cosmetic products. It is also used to help treat acne and prevent tooth decay.
Although benzoic acid has been linked to cancer, the Food and Drug Administration (FDA) has determined that it is safe for use in small amounts.
The FDA has set an upper limit of 0.1 percent of benzoic acid in foods that are labeled “low-acid” or “non-acidified.” The agency also limits the number of other chemicals that can be added to these products because they can react with benzoic acid to form benzene, which causes cancer.
FDA
In food, benzoic acid can be used as an antimicrobial agent, flavoring agent, or adjuvant, with a maximum usage of 0.1%. In feed, it can be used as a preservative or acidifier.
EFSA
According to the Commission Regulation (EU) No 231/2012, benzoic acid (E210) is an authorised food additive.
Safety re-evaluation in 2016
In 2016, EFSA reevaluated its safety along with its salts and determined an acceptable daily intake (ADI) of 5 mg/kg bw/day.
Approved uses
The same applies to sodium benzoate.
UK Food Standards Agency
This item is categorized as “Others”
Food Standards Australia New Zealand
Australia and New Zealand approve it under code number 210.
JECFA
Classification: food additives, antibacterial preservatives.
ADI “5 mg/kg BW” was set in 1996 and no safety concerns as a flavoring agent were evaluated in 2002.
What does benzoic acid do for skin?
Benzoic acid is a common preservative in cosmetics. It’s also found in nature, likely because it has antimicrobial properties. The ingredient is effective at preventing the growth of microorganisms and yeasts, and it can be used to make products that are more stable.
Benzoic acid works by lowering the skin’s pH level, which makes it inhospitable to bacteria. The ingredient also has anti-inflammatory properties that help soothe irritation caused by acne and other conditions.
Benzoic acid is one of the most commonly used preservatives in cosmetics because it’s effective at preventing mold and yeast growth, as well as other microorganisms. Benzoic acid works by lowering the skin’s pH level, making it harder for bacteria to live on the skin or in a product. It also has anti-inflammatory properties that make it useful for treating acne and other inflammatory conditions on your face.
Benzoic Acid VS Sodium Benzoate
Benzoic acid and sodium benzoate are both preservatives that are used to prevent the growth of mold, yeast and bacteria in food products. Benzoic acid is an organic compound that is derived from benzene, while sodium benzoate is a salt of benzoic acid that has been modified to make it water soluble.
Benzoic acid and sodium benzoate are often found together in soft drinks, fruit juice, salad dressing and other foods that have an acidic pH. The reason for this is because they both function as antioxidants and help protect the food from losing its natural color or taste through oxidation. They also inhibit the growth of certain molds and fungi by destroying their cell walls.
While these two compounds have similar properties, they are not interchangeable because each one has different properties that make them useful in different situations. For example:
Sodium Benzoate – Sodium benzoate has been approved by the FDA since 1959 as a food additive and is considered very safe for human consumption at levels up to 0.1% (100 ppm). It does not cause allergic reactions nor does it cause skin irritation like some other preservatives can do when they come into contact with your skin or eyes (source).
Calcium Propionate – Calcium propionate is often used in conjunction with sodium benzoate to fight mold on cheese. Unlike sodium benzoate, calcium propionate does not affect the flavor and color of foods; it also has a longer shelf life. It is considered safe for human consumption at levels up to 0.1% (100 ppm). Some people may experience allergic reactions if they are sensitive to dairy products or calcium-fortified foods (source).
What’re the side effects of benzoic acid?
Benzoic acid is a preservative found in food and cosmetics and as a fungicide. It’s also used in topical medicines, tablets and liquid suspensions.
The side effects of benzoic acid depend on how you use it. Side effects from high doses of benzoic acid may include:
- Drowsiness
- Sleepiness
- Confusion
- Nausea or vomiting
- Rash
- Diarrhea
- Headache
Where to buy benzoic acid?
Benzoic acid is available over-the-counter (OTC) at pharmacies without a prescription. Also, it can be ordered online from specialty chemical suppliers.
Benzoic acid comes in the following forms:
Crystalline powder — This form of benzoic acid is usually used for industrial purposes such as making perfumes, flavors or food preservatives. It may also be used as an ingredient in pharmaceuticals or cosmetics.
Paste/paste — This form of benzoic acid is usually used for industrial purposes such as making perfumes, flavors or food preservatives. It may also be used as an ingredient in pharmaceuticals or cosmetics.
Liquid (aqueous solution) — This form of benzoic acid is usually used for industrial purposes such as making perfumes, flavors or food preservatives. It may also be used as an ingredient in pharmaceuticals or cosmetics
You can be purchased benzoic acid from the following sources:
Online. Companies that sell benzoic acid online include Global Chemicals, Inc., M&M International Trading Limited, Sigma-Aldrich, LLC and others.
Local chemical supply stores. Some local chemical supply stores carry benzoic acid as well, but they may not sell it in bulk amounts.
Grade Chemical. if you buy in bulk amounts, you can consider purchasing from Grade Chemical. they are one reliable benzoic acid supplier in China. for their price is much more competitive than the local market.
Specialty chemical distributors. If you need a lot of benzoic acid, you may find a better price by buying it through a specialty chemical distributor like Carolina Biological Supply Company or Fisher Scientific Co.
Frequently Asked Questions
Is benzoic acid natural?
Benzoic acid is a naturally occurring organic compound that is typically produced by the metabolism of benzene, a chemical compound present in crude oil.
Is benzoic acid vegan?
Yes, benzoic acid is vegan.
Benzoic acid is a naturally occurring organic compound found in many plants, where it serves to defend the plant against bacteria and fungi. Benzoic acid can be extracted from fruits like apples, cranberries, and plums; also from spices such as cinnamon and cloves; or from bark such as cinchona or guaiacum.
Is benzoic acid water soluble?
Yes, benzoic acid is water soluble.
Is benzoic acid bad for your skin?
Yes, benzoic acid can be bad for your skin.
It is an organic acid that is derived from benzoic alcohol, which is found in plants. Benzoic acid has antifungal properties and is used as a preservative in food products, especially those that contain yeast. Because of its antifungal properties, it’s also used in cosmetics to inhibit the growth of mold and bacteria on the skin.
However, like many other ingredients used in cosmetics and personal care products (particularly those with strong antiseptic properties), benzoic acid can be drying to the skin and cause irritation when used repeatedly. It can also cause allergic reactions in some people.
Is benzoic acid a drug?
Benzoic acid is not a drug. It’s an organic compound that occurs naturally in many foods, particularly berries. It’s also used to flavor and preserve food products and can be found in soda, yogurt, and bread.
Is benzoic acid safe during pregnancy?
Yes, benzoic acid is safe during pregnancy. It is a terminal carboxylic acid with the molecular formula C6H5CO2H and has a molecular weight of 146.12 g/mol. Benzoic acid is a white crystalline solid at room temperature and it dissolves in water. but better to consult with your doctor about your condition of use.
Which foods contain benzoic acid?
The following foods contain benzoic acid:
-Citrus fruits (including lemons, limes, oranges, and grapefruit)
-Vegetables such as beets, carrots, spinach, and potatoes
-Many grains such as rye bread, wheat bread and rice
Conclusion
In summary, Benzoic acid is an organic compound that is used as an antimicrobial agent and preservative in many different food products. It is generally considered safe for human consumption, although there have been reports of it causing adverse effects when consumed with certain medications. For this reason, you should be sure to check with your healthcare provider before consuming any products containing benzoic acid.
If you have any questions about this additive, feel free to let us know in the below comments.
