Peroxide Removal from Organic Solvent Tetrahydrofuran

What is THF aka Tetrahydrofuran?

Tetrahydrofuran is an organic solvent that contains four carbons, eight hydrogens and one oxygen atom. It’s a colourless solvent that can be mixed with water. This solvent is otherwise known as oxolone (C4H8O).

THF is commonly used as a solvent, a medium for conducting various chemical reactions, and as a point to start for many chemical synthesis processes .

Peroxides when combined with Tetrahydrofuran (THF)

Peroxides are formed when the chemical compounds are stored for a long period and are then shown to light, heat, moisture etc., which results in a slow oxidation process.

Chemicals that can form peroxides are a category of compounds that are capable of forming hazardous peroxide crystals that can cause explosions.

Among the organic solvents that are used in laboratories, many of them can form these types of dangerous crystals by combining them with peroxides. One such chemical that is widely available and used is tetrahydrofuran.

If peroxide formation takes place in tetrahydrofuran, there is a large possibility of an explosion taking place under mechanical shock or thermal shock. So, a lot of care must be taken in handling them. THF when exposed to air, moisture, heat, light and contaminants can all cause peroxide formation. When these peroxide crystals are formed, they can be seen on the lids or lid lines of the container. They may explode when those lids are opened.

Detection of peroxides in Tetrahydrofuran (THF)

Peroxide test strips can be used to identify the presence of peroxide in the organic compounds.

The presence of peroxide, as well as the amount of peroxide in the tetrahydrofuran solvent, can be identified using these peroxide test strips.

To conduct the test, place the strip in the solvent for a second and remove it. If there is high content of peroxide in the solvent, the strip will change to deep blue, brown or green colour.

Peroxide formation, as well as contamination, can be avoided to an extent by following the steps given below.

As a chemical sensitive to shock and heat, THF mfg. comes under Class C.

•  Identifying the chemical
  • Class A (severe peroxide hazard -if opened, dispose of off in 3 months)
  • Class B (Concentration hazard- if opened, dispose of in 6 months)
  • Class C (Heat & shock-sensitive- if opened, dispose of in 6 months)
  • Class D (chemicals that could form peroxide that is to be decomposed only if peroxide crystals are present)
• Handling is the next step
  • These chemicals which can form peroxides, like THF should only be handled when clearly labelled with the date of receipt and date when it was opened.
• Storing TFH
  • They must be stored in containers that are air-tight and that don’t allow light to pass through them. Even direct sunlight can cause peroxide formation in these bottles.
•  Disposing peroxide forming chemicals
  • These organic solvents which can probably form peroxides in them must be disposed of off even if the bottle is opened in a year.

How to remove peroxides from the organic solvent tetrahydrofuran mfg.?

If the concentration of peroxides in ppm is low, for instance, if it’s less than 30 ppm then it’s considered hazardous and the peroxides can be removed with various procedures like chromatography, distillation, evaporation etc. Peroxide level above 30 ppm is deadly hazardous and is removed with some other techniques.

• Distillation

  When the peroxide level is 0 ppm, the distillation process is used. The vapour steam that contains a fraction of tetrahydrofuran is absorbed by alumina balls and then a peroxide-free THF is obtained as a result of a multi-stage distillation process.

• Evaporation

  It is used when there is a low amount of peroxide. In this process, a significant amount of heat energy is needed and only low level less hazardous peroxides are subjected to the process of evaporation.

• Column chromatography

  In the column chromatographic process, tetrahydrofuran is passed through a column containing activated alumina. This activated alumina in the column absorbs the peroxide and then using some dilute acids like ferrous sulphate, it is flushed and removed. When the activated alumina used in the column are of two forms- powdered alumina and alumina balls, this is what results in the faster rate of absorption of peroxide from the solvent.

  Activated alumina as an absorbent plays a significant role in adsorbing peroxides in all these processes. With its highly porous nature and larger surface are alumina acts as an excellent absorber that can yield a more efficient tetrahydrofuran solvent-free from hazardous peroxides.

  Sorbchem India is a global organization solely devoted to providing adsorbents and desiccants to various industries and has a large number of trusted customers. Superior quality alumina powder, as well as activated alumina balls of various types, are all available here.