Propylene Glycol 40% – USP Grade (C3H8O2)

Product Overview

Propylene Glycol 40% – USP Grade (C₃H₈O₂) is a clear, colorless liquid composed of propylene glycol and water. This USP-grade solution meets strict pharmaceutical standards, delivering reliable solvent properties, low toxicity, and excellent solubility across diverse formulation environments. The ±1% assay range (39–41% w/w, typical 40%) is established by titration with standardized NaOH, ensuring consistent carrier performance in pharmaceutical excipients and industrial processes. Its APHA/Hazen color typically around 5 with a maximum of 10, confirming low impurity coloration and suitability for sensitive analytical and medical applications. The product’s density and viscosity profile, along with a narrow residue after ignition (typical 0.2%, max 0.5%), support precise formulation control and reproducible results in modern manufacturing workflows.

This solution is widely used as a solvent, humectant, and carrier due to its miscibility with water and numerous organic solvents, along with favorable physical properties such as a low vapor pressure and a relatively low boiling point of 188.2°C. The material is packaged and stored under controlled conditions to prevent moisture uptake, with tight specification verification through routine quality checks aligned to ACS/USP/FOOD_GRADE testing protocols. Its compliance with USP-NF Monograph standards and robust impurity profiling support safe integration into pharmaceutical, cosmetic, and industrial formulations.

Key Properties

• Appearance: Clear, colorless liquid
• Cas: 57-55-6
• Molecular Formula: C₃H₈O₂
• Molecular Weight: 76.09 g/mol
• Boiling Point: 188.2°C
• Freezing Point: -59°C
• Specific Gravity (20°C): 1.04–1.045 (typical 1.042)
• Specific Gravity (25°C): 1.036–1.041 (typical 1.039)
• Density (25°C): 1.036 g/mL
• Viscosity (20°C): 46 cP (20°C);
  40 cP (25°C)
• Refractive Index (20°C): 1.431
• Flash Point: 104°C (Celsius); 219°F (F)
• Water Content (Karl Fischer): Max 0.5%; typical 0.2%
• Chloride (Cl⁻): Max 2 ppm; typical 1 ppm
• Nitrate (NO₃⁻): Max 5 ppm; typical 2 ppm
• Ammonium (NH₄⁺): Max 2 ppm; typical 1 ppm
• Sulfate (SO₄²⁻): Max 5 ppm; typical 2 ppm
• Phosphate (PO₄³⁻): Max 2 ppm; typical 1 ppm
• Arsenic (As): Max 0.1 ppm; typical 0.05 ppm
• Heavy Metals (as Pb): Max 0.2 ppm; typical 0.05 ppm
• Iron (Fe): Max 0.2 ppm; typical 0.05 ppm
• Copper (Cu): Max 0.2 ppm; typical 0.05 ppm
• Manganese (Mn): Max 0.2 ppm; typical 0.05 ppm
• Nickel (Ni): Max 0.1 ppm; typical 0.02 ppm
• Lead (Pb): Max 0.2 ppm; typical 0.05 ppm
• Zinc (Zn): Max 0.3 ppm; typical 0.08 ppm
• Aluminum (Al): Max 0.5 ppm; typical 0.1 ppm
• Chromium (Cr): Max 0.3 ppm; typical 0.05 ppm
• Cobalt (Co): Max 0.05 ppm; typical 0.01 ppm
• Calcium (Ca): Max 2 ppm; typical 0.5 ppm
• Magnesium (Mg): Max 5 ppm; typical 2 ppm
• Potassium (K): Max 1 ppm; typical 0.3 ppm
• Sodium (Na): Max 1 ppm; typical 0.3 ppm
• Acidity (Meq): Max 0.5; typical 0.2
• Residue After Ignition: Max 0.005%; typical 0.002%
• Solubility: Miscible with water and many organic solvents
• Vapor Pressure (20°C): 0.1 mmHg
• Decomposition Temperature: > 250°C
• Assay (Wt %): 39–41%; typical 40% (Titration with standardized NaOH)
• Color (APHA/Hazen): Max 10; typical 5
• Available Chlorine: 0%
• Substances Reducing Permanganate: Passes test

Common Applications

• HPLC Mobile Phase: Detailed use as a mobile phase component in reversed-phase chromatography for separating organic compounds in analytical chemistry workflows.
• Pharmaceutical Excipients: Solvent and carrier for active pharmaceutical ingredients in diverse formulations, ensuring compatibility with USP-grade standards.
• Humectant in Food Products: Moisture-retaining agent to improve texture and shelf life while maintaining formulation stability.
• Cosmetic Formulations: Moisturizing solvent and carrier for active ingredients in skin care products, with favorable skin-compatibility.
• Antifreeze Component: Utilized in industrial antifreeze formulations due to low freezing point and high boiling point, contributing to system protection.
• Biopharmaceutical Processing: Used as a non-volatile vehicle in certain manufacturing steps where controlled vapor pressure aids process safety.
• Solvent for Chemical Reactions: Medium for synthesis and purification steps requiring a polar, water-miscible solvent with good solvation properties.
• Parenteral Formulation Support (where permitted): Carrier and processing aid in approved sterile preparation lines, aligned with USP guidelines.

Safety Precautions

Store in a cool, dry place away from direct sunlight and ensure containers are compatible (HDPE or glass). Maintain proper ventilation during handling to minimize inhalation exposure, and use PPE such as gloves and safety goggles to protect skin and eyes from splashes. Regularly inspect packaging for integrity to prevent moisture uptake and contamination, and follow all labeled shelf-life and storage recommendations to preserve product quality.

Emergency procedures: In case of contact with eyes, rinse cautiously with water for several minutes and remove contact lenses if present. For skin exposure, wash with plenty of soap and water and seek medical advice if irritation occurs. If inhaled, move to fresh air and monitor for symptoms; if symptoms persist, seek medical attention. For ingestion, rinse mouth and do not induce vomiting; seek medical attention if feeling unwell. The product is not classified as dangerous for transport but should still be handled according to SDS guidelines and local regulations.

Benefits

✔ USP-Grade Assurance – Meets USP-NF Monograph requirements with strict assay, impurity, and water content specifications to support pharmaceutical and sterile manufacturing needs.
✔ High Purity and Low Impurities – Low chlorine, nitrate, and heavy metal content, enabling reliable performance in sensitive formulations and analytical methods.