Sodium bicarbonate, commonly known as baking soda or bicarbonate of soda, is a chemical compound with the formula NaHCO₃. It is a salt composed of a sodium cation and a bicarbonate anion. Sodium bicarbonate is a white solid that is crystalline, but often appears as a fine powder.
Product name: Sodium Bicarbonate
CAS #: 144-55-8
MOLECULAR FORMULA: CHNaO3
Molecular weight: 84.01
Form: Odorless white crystalline powder or lumps.
Melting Point: >300 °C
pH: 7.8 – 8.2
Solubility: It is soluble in water.
Figure no.1: Structure of Sodium Bicarbonate
Sodium Bicarbonate Usage And Synthesis
|Sodium bicarbonate, which is the compound commonly called baking soda, exists as a white, odorless, crystalline solid. It occurs naturally as the mineral nahcolite, which derives its name from its chemical formula by replacing the “3” in NaHCO3 with the ending “lite.” The world’s main source of nahcolite is the Piceance Creek Basin in western Colorado, which is part of the larger Green River formation. Sodium bicarbonate is extracted using solution mining by pumping hot water through injection wells to dissolve the nahcolite from the Eocene beds where it occurs 1,500 to 2,000 feet below the surface. The dissolved sodium bicarbonate is pumped to the surface where it is treated to recover NaHCO3 from solution. Sodium bicarbonate can also be produced from the trona deposits, which is a source of sodium carbonates.|
Chemical and Physical Properties
|Sodium bicarbonate, NaHC03, also known as sodium acid carbonate and baking soda, is a white water-soluble crystalline solid. It has an alkaline taste, loses carbon dioxide at 270°C (518 °F).and is used in food preparation. Sodium bicarbonate also finds use as a medicine, a butter preservative, in ceramics and to prevent timber mold.|
Sodium bicarbonate occurs as an odorless, white, crystalline powder with a saline, slightly alkaline taste. The crystal structure is monoclinic prisms. Grades with different particle sizes, from a fine powder to free-flowing uniform granules, are commercially available.
|Most sodium bicarbonate in the United States is made synthetically by the reaction of sodium carbonate solution (Na2CO3) with carbon dioxide: Na2CO3(aq) + H2O(l) + CO2(g) → 2NaHCO3(aq). It can also be produced using the Solvay process, which uses ammonia, carbon dioxide, and salt to produce sodium bicarbonate according to the following series of reactions: 2NH3(g) + CO2(g) + H2O(l) → (NH4)2CO3(aq)|
(NH4)2CO3(aq) + CO2(g) + H2O(l) → 2NH3HCO3(aq)
NH4HCO3(aq) + NaCl(aq) → NaHCO3(s) + NH4Cl(aq).
|Sodium bicarbonate, used in the form of baking soda and baking powder, is the most common leavening agent. When baking soda,which is an alkaline substance, is added to a mix, it reacts with an acid ingredient to produce carbon dioxide. The reaction can be represented as: NaHCO3(s) + H+ → Na+(aq) + H2O(l) +CO2(g), where H+ is supplied by the acid. Baking powders contain baking soda as a primary ingredient along with acid and other ingredients. Depending on the formulation, baking powders can produce carbon dioxide quickly as a single action powder or in stages, as with a double-action powder. Baking soda is also used as a source of carbon dioxide for carbonated beverages and as a buffer. In addition to baking, baking soda has numerous households uses. It is used as a general cleanser, a deodorizer, an antacid, a fire suppressant, and in personal products such as toothpaste. Sodium bicarbonate is a weak base in aqueous solution, with a pH of about 8. The bicarbonate ion (HCO3-) has amphoteric properties, which means it can act as either an acidor a base. This gives baking soda a buffering capacity and the ability to neutralize both acids and bases. Food odours resulting from acidic or basic compounds can be neutralized with baking soda into odour-free salts. Because sodium bicarbonate is a weak base, it has a greater ability to neutralize acid odours.|
The second largest use of sodium bicarbonate, accounting for approximately 25% of total production, is as an agricultural feed supplement. In cattle it helps maintain rumen pH and aids fiber digestibility; for poultry it helps maintain electrolyte balance by providing sodium in the diet, helps fowl tolerate heat, and improves eggshell quality.
Sodium bicarbonate is used in the chemical industry as a buffering agent, a blowingagent, a catalyst, and a chemical feedstock. Sodium bicarbonate is used in the leather tanning industry for pretreating and cleaning hides and to control pH during the tanning process. Heating sodium bicarbonate produces sodium carbonate, which is used for soap and glassmaking. Sodium bicarbonate is incorporated into pharmaceuticals to serve as an antacid, a buffering agent, and in formulations as a source of carbon dioxide in eff ervescent tablets. Dry chemical type BC fire extinguishers contain sodium bicarbonate (or potassium bicarbonate).Other uses of bicarbonate include pulp and paper processing, water treatment, and oil welldrilling.
|Sodium bicarbonate is generally used in pharmaceutical formulations as a source of carbon dioxide in effervescent tablets and granules. It is also widely used to produce or maintain an alkaline pH in a preparation.|
In effervescent tablets and granules, sodium bicarbonate is usually formulated with citric and/or tartaric acid; combinations of citric and tartaric acid are often preferred in formulations as citric acid alone produces a sticky mixture that is difficult to granulate, while if tartaric acid is used alone, granules lose firmness. When the tablets or granules come into contact with water, a chemical reaction occurs, carbon dioxide is evolved, and the product disintegrates. Melt granulation in a fluidized bed dryer has been suggested as a one-step method for the manufacture of effervescent granules composed of anhydrous citric acid and sodium bicarbonate, for subsequent compression into tablets.
Tablets may also be prepared with sodium bicarbonate alone since the acid of gastric fluid is sufficient to cause effervescence and disintegration. Sodium bicarbonate is also used in tablet formulations to buffer drug molecules that are weak acids, thereby increasing the rate of tablet dissolution and reducing gastric irritation.
The effects of tablet binders, such as polyethylene glycols, microcrystalline cellulose, silicified microcrystalline cellulose, pregelatinized starch, and povidone, on the physical and mechanical properties of sodium bicarbonate tablets have also been investigated.( 8,9) Additionally, sodium bicarbonate is used in solutions as a buffering agent for erythromycin, lidocaine, local anesthetic solutions, and total parenteral nutrition (TPN) solutions. In some parenteral formulations, e.g. niacin, sodium bicarbonate is used to produce a sodium salt of the active ingredient that has enhanced solubility. Sodium bicarbonate has also been used as a freeze-drying stabilizer and in toothpastes.
Recently, sodium bicarbonate has been used as a gas-forming agent in alginate raft systems and in floating, controlled release oral dosage forms for a range of drugs. Tablet formulations containing sodium bicarbonate have been shown to increase the absorption of paracetamol, and improve the stability of levothyroxine. Sodium bicarbonate has also been included in formulations of vaginal bio adhesive tablets and in carbon dioxide releasing suppositories.
Therapeutically, sodium bicarbonate may be used as an antacid, and as a source of the bicarbonate anion in the treatment of metabolic acidosis. Sodium bicarbonate may also be used as a component of oral rehydration salts and as a source of bicarbonate in dialysis fluids; it has also been suggested as a means of preventing radiocontrast-induced nephrotoxicity.
Sodium bicarbonate is used in food products as an alkali or as a leavening agent, e.g. baking soda.
|It has many functions in cosmetics, including pH adjuster, buffering agent, and abrasive, such as in face or body scrubs. When used in small amounts to adjust and maintain the pH of cosmetic products, baking soda is not a problem for skin; however, when used among the main ingredient in scrub products, it’s simply too abrasive and an ingredient we don’t recommend. The rating for this ingredient pertains to its benefit as a pH adjuster and buffering agent.|