What Are the Main Grades of N-Hexane?
N-Hexane is a six-carbon alkane with the molecular formula C6H14 and CAS Registry Number 110-54-3. It is obtained from petroleum fractions and ranks among the most widely used industrial solvents: a clear, colourless liquid with a characteristic petroleum-like odour and a low boiling point.
Because the commercial product is always a mixture of related hydrocarbons, suppliers sort it into distinct grades according to purity, and each grade is matched to specific end uses. Choosing the wrong grade means either paying for purity a process does not need or accepting impurities that damage product quality or analytical results.
Purity Comparison of Hexane Grades
| Grade | Typical purity | Impurity profile | Typical use |
|---|---|---|---|
| Industrial | 95 – 98 % hexane | Small amounts of other C5 – C7 hydrocarbons | General degreasing, rubber and adhesive work, non-critical synthesis |
| Technical | 98 – 99 % | Lower sulfur and aromatic content | Oil extraction, rubber processing |
| High-purity / laboratory | 99.5 % and above | Minimal impurities | Chromatography, analytical chemistry, pharmaceutical synthesis |
| Food grade | Ultra-low residual impurities | Meets food-contact solvent requirements | Vegetable oil extraction for food production |
What Is Food Grade N-Hexane?
Food grade n-hexane is produced to satisfy the requirements set by food safety authorities, including the FDA in the United States and EFSA in Europe. It is characterised by ultra-low residual impurities and is approved for vegetable oil extraction in food production.
In that process the solvent selectively dissolves oil from oilseeds, and the residual solvent is removed in the downstream refining steps of evaporation and stripping before the oil reaches consumers. Buyers in this segment should always verify the certification documents supplied by the manufacturer, because the grade is defined by compliance rather than by a single purity figure.
Solvent Properties That Drive Grade Selection
Low boiling point – allows easy removal by evaporation or distillation after use.
Low surface tension – helps the solvent penetrate tight spaces and wet surfaces quickly.
Low flash point – demands strict control of ignition sources during handling and transfer.
Low solubility in water – simplifies separation from aqueous systems and speeds phase splitting.
Strong solvency for oils and fats – the reason it dominates oilseed extraction.
How to Choose the Right Grade
Selection depends on the process and on the level of impurity the product can tolerate. General degreasing and cleaning operations run economically on industrial grade material. Oil extraction, rubber processing and similar duties benefit from the tighter specification of technical grade. Laboratories and pharmaceutical manufacturing should use high-purity or laboratory grade to protect the validity of analytical work and the quality of synthesised products. Food production should use only the dedicated food grade, supported by valid certification.
Safe Storage and Handling
N-Hexane is highly volatile and flammable. Keep it in tightly sealed containers in a cool, well-ventilated area away from heat, sparks and open flames. Use explosion-proof equipment and grounding measures during transfer, wear suitable protective clothing and gloves, and avoid prolonged inhalation of vapour. Follow the safety data sheet for the specific grade being handled, since flash point and impurity limits differ between grades.
Frequently Asked Questions
Q: What is the CAS number of n-hexane?
The CAS Registry Number is 110-54-3 and the molecular formula is C6H14.
Q: What purity does industrial grade n-hexane have?
Industrial grade n-hexane typically contains 95 to 98 % hexane together with small amounts of other C5 to C7 hydrocarbons.
Q: Which grade is used for vegetable oil extraction?
Food grade n-hexane, produced to meet food safety authority requirements, is the grade approved for vegetable oil extraction.
Q: Is high-purity n-hexane used in laboratories?
Yes. High-purity or laboratory grade material at 99.5 % or above is used in chromatography, analytical chemistry and pharmaceutical synthesis.
Q: What are the main benefits of n-hexane as a solvent?
Its low boiling point, low surface tension and strong solvency for oils make it effective in degreasing, extraction and synthesis.
Q: Why must n-hexane be kept away from ignition sources?
It has a low flash point and is highly flammable, so it must be stored and transferred away from heat, sparks and open flames.