SODIUM GLUCONATE
Technical Grade
Sodium gluconate is a white granular, crystalline solid which is very soluble in water. It is non corrosive, non toxic, biodegradable and renewable. It is resistant to oxidation and reduction even at high temperatures. The main property of sodium gluconate is its excellent chelating power, especially in alkaline and concentrated alkaline solutions. It forms stable chelates with calcium, iron, copper, aluminium and other heavy metals. It is a more superior chelating agent than EDTA, NTA and phosphonates.
Uses for Sodium Gluconate:
- Used as surface cleaning agent for metals
- Used as cleaning agent of glass bottles
- It also can be used as water reducing agent and retarder in the building industry. Sodium gluconate is also an efficient set retarder and a good plasticiser & water reducer for concrete, cement, mortar and gypsum.
Sodium gluconate in the cleaning industry
Sodium gluconate is commonly found in many household and industrial cleaners. This is because on its multi functionality. It acts as a chelating agent, a sequestering agent, a builder and a redeposition agent. In alkaline cleaners like dishwasher detergents and degreasers it prevents hard water ions (magnesium and calcium) interfering with the alkalies and allows the cleaner to perform to its maximum ability.
Sodium gluconate helps as a soil remover for laundry detergents as it breaks the calcium bond holding the dirt to the fabric and further prevents the soil redepositing onto the fabric again. (see below for more information on using sodium gluconate in Laundry and dishwasher formulations)
Sodium gluconate helps to protect metals like stainless steel when strong caustic based cleaners are used. It helps to break down scale, milkstone and beerstone. As a result it finds application in many acid based cleaners especially those formulated for use in the food industry. (see below for more information)
Industrial Applications of sodium gluconate
Sodium gluconate is used in electroplating and metal finishing because of its strong affinity for metal ions. Acting as a sequestrant it stabilises the solution preventing impurities from triggering undesirable reactions in the bath. The chelation properties of gluconate assist in the deterioration of the anode thus increasing plating bath efficiency. Gluconate can be used in copper, zinc and cadmium plating baths for brightening and increasing lustre.
Sodium gluconate is used in agrochemicals and in particular fertilisers. It helps plants and crops to absorb necessary minerals from the soil.
It is used in the paper and pulp industries where it chelates out metallic ions which cause problems in the peroxide and hydrosulphite bleaching processes.
Sodium gluconate in Construction Industry
Sodium gluconate is used as a concrete admix. It offers several benefits including improved workability, retarding setting times, reducing water, improved freeze-thawing resistance, reduced bleeding, cracking and dry shrinkage. When added at a level of 0.3% sodium gluconate can retard setting time of cement to over 16 hours depending on ratio of water and cement, temperature etc. As it acts as a corrosion inhibitor it helps to protect iron bars used in concrete from corrosion.
Sodium gluconate as a corrosion inhibitor
When sodium gluconate is present in water above 200ppm it protects steel and copper from corrosion. Water pipes and tanks composed of these metals are prone to corrosion and pitting caused by dissolved oxygen in the circulation water. This leads to cavitation and degradation of the equipment. The sodium gluconate reacts with the metal producing a protective film of the gluconate salt of the metal eliminating the possibility of the dissolved oxygen to come into direct contact with the metal.
In addition sodium gluconate is added to deicing compounds like salt and calcium chloride which are corrosive. This helps protect metal surfaces from being attacked by the salts but not deterring from the salt's ability to dissolve ice and snow.
Other industrial applications of importance include bottle washing, photo chemicals, textile auxiliaries, plastics and polymers, inks, paints and dyes and Water treatment.
Properties & specification of sodium gluconate:
- Systematic name: sodium (2R,3S,4R,5R')-2,3,4,5,6-pentahydroxyhexanoate
- Other names: D-Gluconic Acid, Monosodium Salt; Natriumgluconat; D-Gluconsaure; Natriumsalz; Natrium D-Gluconat;
- Purity: 99+%
- CAS No: 527-07-1
- EINECS: 208-407-7
- Molar mass: 218.14 g/mol
- Chemical formula: NaC6H11O7
- Appearance: white crystalline solid
- pH: 6.5-7.3
- Solubility: soluble in water 590 g/l @ 25C
Sodium gluconate is soluble in cold water and hot water. It is only partially soluble in methanol and ethanol.
Health & safety
This product is not classified according to the EU regulations.
Safety phrase: S24/25- Avoid contact with skin and eyes.
PLEASE NOTE: This product is not for human or animal consumption.
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Sodium Gluconate for use in Laundry and Dishwasher formulations:
Sodium gluconate is commonly used in dishwasher and laundry detergents as a chelating agent, which helps to soften water and enhance the cleaning efficiency by binding to metal ions. The typical levels of sodium gluconate used in these products can vary depending on the formulation and specific application. However, general guidelines can be provided:
Dishwasher Detergents:
- Typical Concentration: Sodium gluconate is usually present at concentrations ranging from 1% to 5% by weight in dishwasher detergents.
- Function: It helps to prevent the formation of scale and spots on dishes by sequestering hard water ions (such as calcium and magnesium), thus improving the overall cleaning performance and preventing residue build-up.
Laundry Detergents:
- Typical Concentration: In laundry detergents, sodium gluconate concentrations can range from 0.5% to 3% by weight.
- Function: It serves to enhance the effectiveness of the detergent by binding to metal ions that might interfere with the cleaning process. This helps in maintaining the efficacy of surfactants and other active ingredients, preventing fabric discoloration and enhancing stain removal.
Factors Influencing Concentration Levels:
- Water Hardness: In regions with very hard water, higher concentrations of sodium gluconate might be used to effectively chelate the higher levels of metal ions.
- Detergent Formulation: The presence of other chelating agents and the overall formulation strategy of the detergent can influence the specific concentration of sodium gluconate used.
- Product Type: Different types of detergents (e.g., liquid, powder, pods) may have varying formulations, which can affect the amount of sodium gluconate included.
Use in Caustic Cleaners to protect stainless steel and copper:
The addition of sodium gluconate to caustic-based cleaners can help protect stainless steel and copper surfaces by chelating metal ions and preventing corrosion. The typical concentration range of sodium gluconate in such applications varies, but it generally falls within 0.5% to 2.0% by weight of the total cleaner formulation.
Here are some guidelines:
- Mild Protection: For mild protection, a concentration of around 0.5% to 1.0% by weight may be sufficient.
- Moderate Protection: For moderate protection, use a concentration of 1.0% to 1.5% by weight.
- High Protection: For high levels of protection, especially in more aggressive cleaning environments, a concentration of 1.5% to 2.0% by weight is recommended.
It is essential to consider the specific requirements of your cleaning process and the type of caustic cleaner being used. Additionally, conducting trials to determine the optimal concentration for your particular application is advisable.