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peroxide Removal from THF using activated alumina balls
December 4, 2017


Chemical compounds when stored for a prolonged period and later when exposed to air and light undergo slow oxidation and lead to the formation of Peroxide, which can be visualized in the form of Crystals. The Peroxide thus, formed get detonated on combining with other compounds or when disturbed due to fiction or heat resulting in an explosion. This is because of the Chemicals or Chemical compounds having oxidation and reduction center within the same molecule. Thus, such chemical compounds are instable and undergo auto-decomposition even on exposure to Sunlight. The Presence of peroxides can be detected by using Peroxide test strips. The change in the colour of the strips indicates the presence of Peroxide.

peroxide Removal from THF

Peroxide forming chemicals include Di-isopropyl ether, Di-vinyl acetylene, Sodium amide, Vinylidiene Chloride, Dioxane, Diethyl ether, Tetra hydro Furan. Among these Tetra hydro Furan(C4H8O) also known as Oxolone, is a solvent which is most often used in manufacturing of Rubber, Plastics, Dyes, PVC pies and even in food storage and Packaging material.

THF(Tetra Hydro Furan) PeroxideTest:

Presence of Peroxide indicates the formation of Tetrahydrofuran peroxide formation in the solvent, which can be established by performing THF peroxide Test which gives the concentration of peroxide level in THF solvent. In this test Peroxide test strip is placed in the solvent for 1 second, and then removed. If the strip turns deep blue, green or brown it indicates high peroxide levels in the solvent. The gradations on the color scale 0,5,60,250 and 500ppm indicates the concetation of the peroxide level in THF.

THF peroxide test

Therefore, proper handling of THF{Tetra hydro Furan)Mfg is necessary as it stimulates  the rate of peroxide formation within a short time. By following the guidelines by EH&S, which are given below not only slows down the rate of peroxide formation but also prevents the peroxide contamination.

 

Best Guidelines for removal of peroxide from THF (Tetra Hydro Furan)

  • Identification: Based on peroxide formation, Identify the Chemical, which are classified into

Class A: Severe Peroxide Hazard, which need to be disposed off within 3 months if opened.

Class B: Concentration Hazard, need to be disposed off within 6 months if opened.

Class C: Shock and Heat Sensitive, need to be disposed off within 6 months if opened.

Class D: Potential Peroxide forming Chemicals need to be disposed off only if peroxide crystals      are Present.

Therefore, THF (Tetra Hydro Furan)Mfg is considered as a Class C, Chemical as it is Shock and Heat Sensitive.

  • Handling: Handle the peroxide forming chemicals, such as THF (Tetra Hydro Furan)Mfg only when labeled with Date received and Date opened .
  • Storage: Do not store, Peroxide forming Chemicals such as THF (Tetra Hydro Furan)Mfg in direct sunlight as it accelerates peroxide Formation. Store in a tightly closed, air-impermeable, light resistant containers.
  • Disposal: Peroxide forming Chemicals, such as THF (Tetra Hydro Furan)Mfg must be disposed off, even if unopened within a time frame of 1year.

Procedures for the Removal of Peroxides in THF (Tetrahydrofuran) Mfg:  

Procedures for the Removal of Peroxides in THF (Tetrahydrofuran)

Removal of peroxides is performed by various methods, in which absorption by Activated Alumina is considered as an efficient process. Removal of Peroxides is possible only if the concentration of peroxide, in parts per million is low, such as-

  • If the concentration of Peroxide level is less than 30ppm, it is considered has Hazardous. Thus formed peroxide is removed either by Distillation Process or by Evaporation process or by Chromatography process.
  • But if the concentration of Peroxide level is greater than 30ppm, it is considered has deadly Hazardous and need to be disposed off  carefully using a suitable procedure.

Distillation:  

Distillation process is employed for the THF(Tetrahydrfuran)mfg containing only 0ppm of Peroxide. In this process the THF fraction of vapour steam is absorbed by the Activated Alumina Balls after which a multi-stage distillation is run which gives a peroxide free THF.Since, Distillation eliminates the inhibitor if present , enhancing peroxide formation, it is a less often used procedure.

Evaporation :

Evaporation process requires a significant amount of heat, which is why employed for removal of low level of Peroxides. Since this evaporation process is performed in a rotary evaporator containing round bottomed flask, only low level peroxides which possess less hazard are said to be subjected to Evaporation. Hence it is considered as the safe procedure only for low Volumes of THF(Tetrahydrfuran)Mfg.

Chromatography:

Column Chromatography which consists of a glass tube with bottom portion of the column packed with glass wool or cotton wool, above which the absorbent, Activated Alumina powder slurred is poured and a paper disc is placed above it. Then peroxide contamiated THF(Tetrahydrfuran)Mfg solvent is added to the column, which slowly passes through the packed column and gets eluted on removing the glass wool which is collected in a brown glass bottle . The Peroxide free THF(Tetrahydrfuran) thus obtained is filled with an inert gas to prevent reformation of Peroxide on contact with Oxygen. The peroxide absorbed by the Activated Alumina in the Column is then flushed with suitable dilute acids such as Potassium Iodide or Ferrous Sulfate in order to remove the peroxide that is absorbed.

peroxide Removal from THF using activated alumina power via chromatography

THF(Tetrahydrfuran) being a water-misscible organic solvent, is passed on through Activated Alumina,in  the Column , which absorbs the peroxides present in the Solvent .In Chromatography, Absorbent plays a main role in peroxide removal . On the other hand Activated Alumina being available in Activated Alumina powder form and Alumina Ball form absorbs the peroxides at a faster rate.

ACTIVATED ALUMINA

Activated Alumina being porous in nature with a high surface area absorbs Peroxide by intermolecular attraction force, until equilibrium is attained between the Solvent and the Solute in the Column. As the Activated Alumina can be slurred it act as a best Absorbent to yield high efficient peroxide free THF(Tetrahydrfuran).

ALUMINA BALLS

Alumina under heat or pressure gets molded into a solid mass material and is referred to as Alumina Balls. Alumina Balls act as a Catalyst better than absorbent because of uniform and regular shape increase the distribution of the THF solvent, thereby holding the contaminant, i.e, Peroxide .

ACTIVATED ALUMINA BALL

Alumina under heat or pressure gets molded into a solid mass material and is referred to as Alumina Balls. These are white in color, spherical in shape and they are available in a size ranging from 25mm to70mm.Activated Alumina Balls which act as Catalyst in Hydrogen peroxide production is also used to trap the peroxides when the THF (Tetrahydrfuran) peroxide solvent is run through the Vertical Columns containing Activated Alumina Balls.

Activated Alumina price hike seems to be inevitable with the growing need at Industrial level as well as for new technologies and researches.

activated alumina balls

Uses Of Activated Alumina:

  • Commercially available techniques for water purification such as Ultra filtration, Membrane separation, Reverse Osmosis , Adsorption and many more rely on the sorbent – Activated Alumina.
  • Activated Alumina is also used for Hydrogen Purification, Feedstock drying, Solvent Purification.
  • Drying CO2 in Breweries, inert gas drying, Removal of H2S from natural gas , Polymer Purification is also performed by Activated Alumina.
  • LPG sweetening, Propane Sweetening, LNG sweetening is also achieved through Activated Alumina.
  • TBC removal from Styrene, Butadiene during Polymerization is also carried on by Activated Aumina.