Propylene Glycol Insights
Shell Food Grade Propylene Glycol vs Cosmetic Grade Propylene Glycol: Physical and Chemical Property Comparison
The products compared in this article are from actual Shell batches produced in March and May 2026 and supplied to Henan Tongshang’s Zhengzhou warehouse.
As an authorized distributor of Shell propylene glycol products, Henan Tongshang would like to share a comparative analysis of the physical and chemical properties of Shell food grade propylene glycol and Shell cosmetic & personal care grade propylene glycol.
The products compared in this article are from actual batches produced by Shell in May 2026 and shipped to Henan Tongshang’s Zhengzhou warehouse. The detailed comparison is as follows:
Comparison of Shell Food Grade Propylene Glycol and Cosmetic Grade Propylene Glycol
| Test Item | Food Grade Propylene Glycol | Cosmetic Grade Propylene Glycol | Difference Analysis |
|---|---|---|---|
| Purity | >99.90% m/m | >99.90% m/m | Both achieve extremely high purity standards |
| Specific Gravity (25/25°C) | 1.0355 | 1.0355 | No difference in physical density |
| Monoethylene Glycol | <0.0005% m/m | <0.0005% m/m | Same level of toxic impurity control |
| Diethylene Glycol | <0.0005% m/m | <0.0005% m/m | Same level of toxic impurity control |
| Dipropylene Glycol | 0.0168% m/m | Not tested | Additional impurity monitoring item for food grade |
| Propylene Oxide | <0.0005% m/m | Not tested | Additional key toxic substance control for food grade |
| Initial Boiling Point | 187°C | Not tested | Additional distillation range evaluation for food grade |
| Dry Point | 188°C | Not tested | Additional distillation range evaluation for food grade |
| Water Content | 0.005% m/m | 0.005% m/m | Extremely low moisture control with no difference |
| Iron | <0.020 mg/kg | <0.020 mg/kg | Same metal impurity control level |
| Chloride (as Cl-) | 0.01 mg/kg | 0.01 mg/kg | Same chloride ion content |
| Residue on Ignition | <10 mg/kg | <10 mg/kg | Test method updated according to CP-2025 |
| Heavy Metals (as Pb) | <5 mg/L | <5 mg/L | Test method updated according to CP-2025 |
| Lead (Single Element) | <0.020 mg/kg | Not tested | Additional strict lead control for food grade |
| Arsenic Compounds | <0.0002% m/m | <0.0002% m/m | Same toxic element control level |
| Acidity (as Acetic Acid) | 0.0007% m/m | 0.0006% m/m | Both far below specification limits |
| Acidity (0.1N NaOH) | 0.012 ml | 0.011 ml | Normal minor batch variation |
| Acidity (0.01N NaOH) | 0.56 ml | 0.52 ml | Normal minor batch variation |
| Color (Pt-Co) | 2 | 1 | Both are clear and transparent, far below limit of 10 |
| Odor / Appearance / Infrared | Pass | Pass | No difference in sensory and qualitative identification |
Key Differences and Quality Control Analysis
1. Similar Core Quality Standards
The comparison shows that Shell cosmetic grade and food grade propylene glycol maintain the same high-level manufacturing standards in core indicators, including:
- Purity (>99.90% m/m)
- Water content (0.005% m/m)
- Control of key impurities such as monoethylene glycol and diethylene glycol
The main differences between the two grades are not basic product quality, but rather the scope of testing and compliance requirements based on different application fields.
2. Food Grade Has More Strict Safety-Oriented Testing Requirements
Due to the higher compliance requirements for products involving food contact, oral applications, or pharmaceutical-related uses, food grade propylene glycol includes additional inspection items.
These include:
- Distillation range testing (initial boiling point and dry point) to better evaluate component distribution;
- Dipropylene glycol content analysis to control related impurities;
- Propylene oxide testing for trace-level toxic substance monitoring;
- Individual lead testing with strict limits to ensure product safety.
These additional tests reflect the higher safety requirements of food/pharmaceutical-related applications.
3. Differences in Testing Standards and Batch Variation
The cosmetic grade batch (production date: 2026-05-02) and food grade batch (production date: 2026-03-30) follow different testing requirements.
The food grade batch has adopted testing methods aligned with the latest Chinese Pharmacopoeia (CP-2025) requirements, while some tests for cosmetic grade products follow previous CP-related standards.
Minor differences in indicators such as:
- Color value (1 vs 2)
- Acidity (0.011 ml vs 0.012 ml)
are considered normal production batch variations and do not represent any significant difference in product performance.
Shell Propylene Glycol Stock Supply in China
Henan Tongshang maintains inventory of Shell propylene glycol products in multiple warehouses across China, including:
- Shell Food Grade Propylene Glycol
- Shell Cosmetic & Personal Care Grade Propylene Glycol
- Shell Dipropylene Glycol
We provide:
- Product samples
- COA / SDS documents
- Qualification documents
- Supply and pricing information
For more information about Shell propylene glycol products, please contact Henan Tongshang’s sales team.