Chemicals and Solvents

Ethanol, or Ethyl Alcohol, is a clear, colorless, flammable liquid with high volatility. Produced from the dawn of mankind, alcohol is ingrained in human history. Available in many concentrations, grades, and purities, it has applications in food, medicine, and manufacturing. Due to its unique solvation properties, ethanol is used by oil extraction specialists, as a denaturant for tissue cultures, and even in universities to conduct lab experiments. 

Since alcohol is also considered a drug, it is regulated by federal and state agencies. Choosing the right type of ethanol, denatured or undenatured, is critical for cost, quality and safety.

History of Denatured Ethanol

By 1906, methanol, or wood spirits, was added to ethanol so it could be used for industrial purposes at lower tax rates [1]. During Prohibition, even more toxic chemicals were added to alcohol to discourage drinking. Today, denaturized alcohol, or methylated spirits, might contain methanol, isopropyl alcohol, acetone, ketones, or other poisons. Undrinkable, it is exempt from federal alcohol excise tax. The TTB, the Alcohol and Tobacco Tax and Trade Bureau, regulates the taxation, formulations, permitting and uses of both ethanol and undenatured ethanol. 

Ethanol

Ethanol intended for foods and fuels is typically produced by fermenting grains and distilling off the ethyl alcohol. When ethanol reaches 95.6% concentration, it quits boiling separately from water, forming an azeotrope. Although ethanol boils at 78.2°C, and water boils at 100°C, the azeotropic mixture boils at lower temperature of 78.4°C. To concentrate ethanol to 99.5%, the water must be removed by molecular sieves, pressure-swing distillation, or another method.

200 proof alcohol means that the ethanol does not contain water. An anhydrous ethanol solution can be denatured with 95% ethanol and 5% methanol, and it is still 200 proof. Pure alcohol is non-denatured.

Denatured Ethanol 

Denatured alcohol can contain 70-99% ethyl alcohol and is most often denaturized with at least 5% methanol. Unfit to drink, denatured ethanol is exempt from federal alcohol excise taxes for approved end-uses. A link to information on industrial (nonbeverage) alcohol is below:

• https://www.ttb.gov/industrial/industrial-alcohol-denatured-alcohol
• https://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&sid=f7866313787bfcfb2b9cd25ba6af81b5&rgn=div5&view=text&node=27:1.0.1.1.17&idno=27#27:1.0.1.1.17.7.253.1

Reagent grade ethanol, a type of specially denatured alcohol (SDA), is 200-proof ethanol that is denatured with 5% methanol and 5% isopropyl alcohol. If used for manufacturing, you must hold a permit as a specially denatured alcohol (SDA) user. The TBB formula for reagent grade ethanol is SDA-3A. In educational settings, it is a popular solvent for conducting biochemistry or chemistry experiments. In industry, it can be used for manufacturing coatings, cosmetics, detergents, perfumes, pharmaceuticals, printing inks, polymer solutions, or vaccines. SDA-3A can be obtained in small amounts for scientific uses without a permit. When ordering in a container more than 4 liters, you must file an application with the TBB  unless you are qualified to receive bulk shipments. 

Ethanol enters the cell was through the lipid bilayer membranes in nanoseconds, interacting with the hydrophobic portions of the protein and quickly replacing water in the cell [2]. Successive solutions of 70%, 95% and 100% ethanol may facilitate dehydration. The isopropyl present in reagent grade ethanol might even aid paraffin infiltration.

Non-Denatured Ethanol

Non-denatured ethanol is at least 95% concentration and contains no co-solvents or additives. If subject to excise tax, it is more expensive, but a permit may not be required. You must be 21 to purchase it. [Note: A permit may be required to purchase non-denatured ethanol in your state. Check state laws and consult with your EHS coordinator before ordering.]

Tax-free Alcohol is pure non-denatured 99.6% ethyl alcohol. Hospitals, charity clinics, government labs and universities can qualify for tax-free usage with permit approval. Lab students might use non-denatured ethanol to learn how to run GC or to conduct synthetic organic reactions. Hospitals pharmacies can compound prescriptions or run analyses with pure ethanol. Since it is hydroscopic, it should remain tightly capped.

Non-Beverage Drawback

When using food-grade non-denatured ethanol to manufacture a non-beverage food, flavor, or perfume, you may be able to claim a return on TBB alcohol excise tax.

Industrial (Non-Beverage) Ethanol

Pure non-denatured ethanol does not contain adulterants and is a popular tool for manufacturing culinary extracts, essential oils, tinctures, and even tobacco flavors. If pure ethanol is a raw material for foods or beverages, federal excise tax might apply. Because ethanol is a polar solvent, it will extract both water and oil soluble components, like chlorophyll and terpenes. In cold-process extraction, it might prevent heat-induced degradation. Whether used as a processing agent for winterization or as a wash for other extraction processes like CO2, ethanol is a popular choice for extraction specialists. Since it is pure, it leaves little to no residual. For disinfection purposes, 70-90% works best. 

Safety

Ethanol is a flammable, mildly toxic liquid that can be ignited at most ambient temperatures. Flashback along a vapor trail could occur and it could explode if in an enclosed area. 

NEVER mix with Piranha solution, because contact with sulfuric acid and potassium or hydrogen peroxide can cause explosions. 

Skin contact should be avoided, so gloves (like Neoprene, Butyl, or Viton), goggles, and appropriate ventilation (fume hood) should be used. Since reagent grade denatured ethanol is more toxic than non-denatured ethanol, because it contains methanol and isopropyl alcohol, always review your SDS for guidelines.

Conclusion

Ethanol, a universal solvent, has many applications both in science and industry. Non-denatured ethanol is an eco-friendly choice for extraction specialists. Histology clinics use non-denatured ethanol for conducting cell tissue fixation. Whether you need denatured or non-denatured ethanol, Lab Pro has the right grade for your needs.

For over 40 years, Lab Pro has been committed to delivering a complete chemical inventory including ethanol for laboratories worldwide. Come visit the biggest Lab Supply showroom in California, or contact us online or at 888-452-2776.

 

Disclaimer: These chemicals are meant to be used for research, industrial work, cleaning or disinfecting and should always be stored out of the reach of young children or infants. 

Refrences: 

1  Ind. Eng. Chem.192315101086-1087 Publication Date:October 1, 1923:  https://doi.org/10.1021/ie50166a054

2  Biophys J. 2006 Feb 15; 90(4): 1121–1135. Published online 2005 Dec 2. doi: 10.1529/biophysj.105.062364: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1367264/