CIT6883 Citric Acid Anhydrous Powder CAS No. 77-92-9

Anhydrous Citric Acid Powder Description

Anhydrous Citric Acid Powder is a hygroscopic, free-flowing crystalline solid with a molecular weight of 192.12 g/mol and a decomposition point of 175°C. Its triprotic carboxylic acid structure enables strong chelation of divalent and trivalent metal ions (e.g., Ca²⁺, Fe³⁺), enhancing its functionality in sequestration applications. The compound exhibits high water solubility (147 g/100ml at 25°C), moderate solubility in ethanol (38 g/100ml), and negligible solubility in non-polar solvents. It features an acidic taste profile (pKa₁=3.15, pKa₂=4.77, pKa₃=6.40) allowing precise control over acidity in formulations. Thermogravimetric analysis confirms stability below 70°C, with decomposition occurring above 175°C with the release of carbon oxides. The regulatory qualities include a moisture content of ≤0.5%, a sulfate ash content of ≤0.7%, and controlled oxalate/calcium impurities according to USP monographs, ensuring consistency from batch to batch for GMP manufacturing.

Anhydrous Citric Acid Powder Applications

Food and Beverages: Primary acidulant in carbonated beverages, jams, and confections (E330); pH modifier for dairy products and canned foods.

Pharmaceutical Products: Buffering agent in effervescent tablets (5-20% w/w); excipient for controlled release formulations; anticoagulant in blood collection tubes.

Industrial: Descaling agent for boilers (5-15% solutions); chelating agent in plating baths; biodegradable detergent component (replaces phosphates).

Biotechnology: Component of cell culture media (e.g., Krebs-Ringer buffer); metabolite in studies of the citric acid cycle.

Packaging of Anhydrous Citric Acid Powder

Our products are packaged in customised cartons of various sizes tailored to the dimensions of the material. Smaller items are securely packed in PP cartons, while larger items are placed in bespoke wooden crates. We ensure strict compliance with package adaptation and the use of suitable cushioning materials to provide optimal protection during transport.

Packaging: Carton, wooden crate, or customised.

Please refer to the packaging details for your information.

Manufacturing Process

1)Testing Procedures

(1) Chemical composition analysis - Verified with techniques such as GDMS or XRF to ensure compliance with purity requirements.

(2) Mechanical properties testing - Includes tensile strength, yield strength, and elongation tests to evaluate material performance.

(3) Dimensional measurement - Measures thickness, width, and length to ensure compliance with specified tolerances.

(4) Surface quality inspection - Checks for defects such as scratches, cracks, or inclusions through visual and ultrasonic examination.

(5) Hardness testing - Determines material hardness to confirm uniformity and mechanical reliability.

For detailed information, please refer to the SAM Testing Procedures.

FAQs about Anhydrous Citric Acid Powder

Q1. What is the difference between anhydrous and monohydrate citric acid?

Anhydrous (CAS 77-92-9) contains ≤0.5% water, while monohydrate (CAS 5949-29-1) crystallises with one water molecule (8.5-9.0% water). Use anhydrous for moisture-sensitive formulations (e.g., powder blends) and monohydrate where water activity is tolerable (e.g., liquid syrups).

Q2. Can anhydrous citric acid replace phosphates in detergents?

Yes, at 2-7% w/w, it acts as a biodegradable chelator for Ca²⁺/Mg²⁺ ions (stability constant log K = 3.5 at pH 6-9). Its lower binding capacity compared to STPP requires additional binders (e.g., zeolites) in hard water (>180 ppm CaCO₃).

Q3. What precautions are required when handling powdered citric acid?

Respiratory protection: Use N95 masks (Dust PEL = 15 mg/m³ OSHA)

Storage: Maintain humidity <60% to prevent clumping; hygroscopicity increases above 65% RH.

Reactivity: Avoid contact with strong oxidisers (e.g., hypochlorite) - produces chlorine gas.

Related Information

1.Common Preparation Methods

Commercial anhydrous citric acid powder is produced through submerged fermentation of sucrose or molasses by Aspergillus niger strains under controlled aeration (28-30°C, pH 5-6). The resulting broth is filtered to remove mycelia and subsequently precipitated as calcium citrate tetrahydrate by adding lime. After treatment with sulphuric acid to release citric acid, the solution is purified through activated carbon adsorption and ion exchange. Crystallisation occurs through vacuum evaporation at 40-50°C, followed by centrifugation to isolate the crystals. Final dehydration at 70°C under reduced pressure yields the anhydrous form, which is ground and sieved to achieve a uniform particle size (typically 150-850 µm).