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Sodium Benzoate – Uses, Structure and Properties

Jan 25, 2023

What is Sodium Benzoate? 

What aids the breaking of microbial growth in these items? This article will let you know about sodium benzoate food preservative chemicals and whether it is safe to add them to food or not. Let’s have a look.

You are aware that chemistry is all around you. Everything is about chemistry, whether you talk about cleanliness or clothes, from toothpaste to synthetic fibre. It is not limited to food, drugs, or explosives either. You must have tasted packed food items like pickles, ketchup, etc. and are quite aware of the term food preservatives. But have you ever wondered what is added to these foods that make them last longer?


What are Food Preservatives?

Chemical substances used to preserve or protect food against bacteria, moulds, and yeasts are called preservatives. They prevent the spoilage of food due to microbial growth.

Preservatives are generally divided into two classes:

  1. Class I: Some common preservatives like table salt, sugar, and vegetable oil are considered in this class of food preservatives.
  2. Class II: Some common food preservatives of this class are sodium benzoate, sodium metabisulphite, sorbic acid and its salt, epoxides, and p-Hydroxybenzoate esters.

What Is the Meaning of Sodium Benzoate(C₇H₅NaO) Food Preservative?

It is the most commonly used food preservative. It is a sodium salt of benzoic acid produced by the neutralisation reaction of benzoic acid and sodium hydroxide.

Sodium benzoate food preservative is used to control the growth of bacteria and moulds. It also helps to prevent fatty food items from becoming rancid. Although the compound is not found naturally, it is found naturally in various plants and animals.


Structure of Sodium Benzoate(C₇H₅NaO)

It is an aromatic chemical compound with the chemical formula C₇H₅NaO₂.

The structure of sodium benzoate preservative is given below:


Sodium Benzoate

Preparation of Sodium Benzoate(C₇H₅NaO)

Commercially, there are three ways to manufacture sodium benzoate. These are

  1. Naphthalene is oxidized with vanadium pentoxide (V₂O₅) to give phthalic anhydride. After that, it is decarboxylated, i.e., carbon dioxide is removed, to yield benzoic acid. Then, it is converted into sodium salt.
  2. Toluene is mixed with nitric acid and oxidized to produce benzoic acid. Then, it is converted into sodium salt.
  3. Benzotrichloride is hydrolyzed and then treated with a mineral acid to give benzoic acid. Then, benzoic acid is converted into its sodium salt, i.e., sodium benzoate. The reaction of toluene and chlorine forms Benzotrichloride.

Properties of Sodium Benzoate(C₇H₅NaO)

The properties of sodium benzoate preservatives are as follows:

  1. Its molecular formula is C₇H₅NaO₂ and is also known as the sodium salt of benzoic acid.
  2. The molecular mass is 144.105 g/mol.
  3. It is a colourless and odourless crystalline dry powder or granules.
  4. It is a manufactured additive produced by the neutralisation reaction of benzoic acid with sodium hydroxide.
  5. It has a sweet and astringent taste.
  6. The boiling point of  preservative is 450-475°C, and the melting point is 410°C.
  7. Its density is 1.497 g/cm³ and is freely soluble in water, liquid ammonia, and pyridine.
  8. It is stable under recommended storage conditions.
  9. It is metabolised by conversion into hippuric acid, C₆H₅CONHCH₂COOH, which is ultimately excreted in the urine.
  10. On hydrolysis, it dissociates and forms sodium ions (Na⁺) and benzoic acid ions (C₆H₅COO⁻).

The Function of Sodium Benzoate as a Food Preservative

Because of its antibacterial characteristics, sodium benzoate is employed as a preservative in pharmacies as well. Benzoic acid, the parent compound of sodium benzoate, is a good preservative. However, when added to sodium hydroxide, i.e., NaOH, it increases its solubility in different solvents. Therefore, sodium benzoate, i.e., the salt formed, works more ably as a food preservative.


The mechanism of dissociation works behind the preservation of food items. When added to food items, it gets dissociated into benzoic acid and sodium chloride. The development of bacteria is inhibited by benzoic acid and sodium chloride, as both are toxic to microbes.

Uses for Sodium Benzoate(C₇H₅NaO)

As the most common food preservative, sodium benzoate has many applications. Some uses are as follows:


1. In the food industry:

In the food industry, sodium benzoate prevents spoilage from harmful yeasts, bacteria, and moulds. Uses of sodium benzoate also include maintaining freshness in food by helping to prevent or slow down the rate of changes in flavor, color, texture, and pH. Some sodium benzoate foods are

  1. Pickles
  2. Salad dressings
  3. Condiments
  4. Sauces
  5. Wines
  6. Fruit juices
  7. Frozen yogurt
  8. Snack foods

2. In beverages:

It is used as a preservative in soft drinks to accelerate the acid flavor and as a preservative to extend the shelf life. It is used to protect the taste and as an antimicrobial agent. It is commonly found in the ingredient lists of Sprite and Fanta. Some of its foods and beverages are

  1. Soda
  2. Diet soft drinks
  3. Bottled lemon juice
  4. Jelly
  5. Wine coolers
  6. Salad dressing
  7. Soy sauce
  8. Fruit juices
  9. Maple syrup
  10. Some other condiments

3. In cosmetics and personal care products:

Like food and beverage products, cosmetics and personal care products also need preservatives to prevent the growth of bacteria and have anti-corrosive properties. Without preservatives, natural products are unable to be stored for a long time. Some personal care products that include sodium benzoate preservatives are

  1. Hair products
  2. Mouthwash
  3. Moisturizers
  4. Sunscreen
  5. Baby wipes
  6. Serums

4. In pharmaceuticals:

Due to its antimicrobial properties, It is also used in pharmaceutical products. It is used as a preservative in some over-the-counter and prescription medications, especially in liquid medicines such as cough syrup. It is also used in the formulation of tablets, capsules, etc.

5. Other uses:

  1. It is also used in fireworks. It works as fuel in a whistle mix.
  2. It also has industrial uses, such as corrosion inhibitors.
  3. It is used as a stabilizer in photo processing.
  4. It is used to improve the strength of some types of plastic.

Is the Function of Sodium Benzoate as a Food Preservative Safe?

Sodium benzoate is generally recognized as safe and can be used as a flavoring and antimicrobial agent in food with maximum usage of 0.1%. It is also usually considered safe (GRAS) as a food preservative. The maximum allowable level in drinking water by the FDA is 5ppb. Under this level, there is no threat to health.

Therefore, almost all beverages are produced under this limit. Many people are generally cautious about all chemical additives. That also includes sodium benzoate. Fundamental studies raise questions about its safety, but there is a need to research more about this.

Pregnancy: Although it is normally considered safe to consume during pregnancy, it is best to consult your physician before ingesting sodium benzoate foods.

Cancer: It can be converted into benzene. When it is mixed with vitamin C (ascorbic acid), which is present in some soft drinks and other beverages, it turns into benzene. And benzene is a carcinogenic product that may cause cancer. Diet products are more prone to forming benzene, as the sugar in them reduces its formation.

Also, exposure to beverages to heat and temperature accelerates benzene formation. Although no recent publishes product analyses by FDA it has stated that the use of low levels of benzene in drinks does not pose any health risk. Still, detailed studies are needed.

Allergies: Some people may be sensitive to preservatives such as sodium benzoate and may experience allergic symptoms such as itching and swelling.

Inflammation: Some studies and animal tests show that the function of sodium benzoate in foods and drinks could cause low-level inflammation in the body. People suffering from obesity may face more danger.

Some other health concerns because of the function in foods and beverages are

  • Attention Deficit Hyperactivity Disorder (ADHD)
  • Appetite control
  • Oxidative stress


Sodium benzoate is a preservative added to packaged foods, some sodas, and personal care products to prolong their shelf life. It does not occur naturally. Hence, it is made in laboratories. It is a versatile chemical with medicinal, preservative, and other functions.

Sodium benzoate is widely used for preserving beverages, emulsions, foods, toiletries, pharmaceuticals, pastes, adhesives, cleaners, and polishes. It is also used in jellies, fruit salads, sauces, and salad dressings. Still, you may be more sensitive to sodium benzoate. In such conditions, consult a medical practitioner for appropriate testing if you suspect you have an allergy to it.

Frequently Asked Questions

1. Are there any medical uses for sodium benzoate?

A. Yes. Research has proved that taking it in large doses may treat certain medical conditions. Its medicine may be used to treat high blood ammonia levels. Some medicinal uses of this are in the following diseases:

  • Schizophrenia
  • Depression
  • Multiple sclerosis (MS)
  • Maple syrup urine disease
  • Panic disorder

2. What are the alternatives to consuming sodium benzoate?

A. For people cautious about benzene exposure, the FDA advises avoiding buying soft drinks that list both ascorbic acid and sodium benzoate or its erythorbic acid. Instead of preserved foods or sodium benzoate foods and drinks, you can take the following food products:

  • Vegetables (nothing pickled)
  • Fresh fruit
  • Water
  • Pressed fruit juice

3. How should we convert benzoic acid into sodium benzoate?

A. The following steps need to be followed to convert benzoic acid into this:

Step 1: Dissolve benzoic acid into sodium hydroxide solution.

Step 2: This reaction will produce sodium benzoate and water.

Step 3: To crystallize the sodium benzoate, evaporate the water.

Sodium Benzoate


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