Phenol for Bakelite comes from coal tar, where it is concentrated in the middle-oil fraction distilled at roughly 170-230 degrees Celsius and purified by crystallisation, or in lower yield from the tar and liquor of wood distillation. Phenol is dangerous because it numbs the skin it burns: a splash can destroy tissue and be absorbed into the body while hurting little at first, so the correct response is immediate, prolonged flooding with water and removal of contaminated clothing.
Part of Plastics and Polymers
Phenol, or carbolic acid, is the aromatic alcohol that reacts with formaldehyde to form Bakelite and is recovered from coal tar or wood tar.
Coal Tar Is The Main Source
Heating coal without air gives coal gas, tar and coke: see Coal Tar. Distilling the tar separates it into fractions. Coal Tar Distillation puts phenol in the middle (carbolic) oil, collected at 170-230 °C, and says a narrower re-distilled cut at 180-195 °C is richer in phenol. Plastics from Scratch gives 180-185 °C as the crude phenol fraction. The two cuts overlap on the same range, and phenol itself boils at about 182 °C (general knowledge).
Purification by crystallisation: phenol melts at about 41 °C, so cooling the fraction slowly lets it separate as crystals, which are filtered off. The coal-tar article gives the middle oil as 8-12% of the tar, so 100 kg of tar gives 8-12 kg of middle oil, and the phenol is only part of that. Plan on a small yield from a lot of tar.
Wood Is A Weaker Source
Destructive distillation of hardwood gives pyroligneous acid that contains a little phenol and cresols. The scratch carrier calls it low yield but universally available. Wood tar processing is in Wood Tar Production. Cresols are also toxic and behave like phenol.
Salvage As A Source
Where phenol is already around, as old disinfectant or stocks of carbolic, it is the same chemical. The sensible alternative to synthesis is to use salvaged phenolic parts directly: see Bakelite.
Why Phenol Is Underestimated
Phenol is a local anaesthetic as well as a corrosive. It denatures protein and, as it does, deadens the nerve endings, so the skin may turn white and numb with little pain. The person feels no alarm, does not wash it off, and phenol is absorbed through the skin meanwhile. Absorbed phenol is poisonous to the whole body, not just the skin, and affects the nervous system and the heart (general knowledge). A small area of contact can matter. This mechanism is why people underestimate a splash, and is the reason the reaction must be immediate.
Response if phenol contacts skin:
- Get the person away from the source and remove contaminated clothing at once, without letting it touch more skin.
- Flood the area with large amounts of water, for a long time.
- If polyethylene glycol (PEG 300 or 400) is available, it is the standard decontaminant for phenol on skin (general knowledge). Use it on a swab, followed by water.
- Seek medical help even if the skin looks and feels fine, because systemic effects can follow.
The corpus’s coal-tar article says to wash with large amounts of water and then alcohol or glycerin. Water first, in volume, is common to both. This page changes neither the corpus text nor its doses.
Eyes: flood with water continuously and seek medical help. Phenol in the eye is an emergency.
Worked Example: Phenol From A Load Of Tar
From 100 kg of tar the middle oil is 8-12 kg. If phenol makes up one third of that (an assumed fraction), the phenol is 2.7-4.0 kg: 8 / 3 = 2.7 kg to 12 / 3 = 4.0 kg. The one-third fraction is an illustration, not a corpus figure, so measure your own. The next articles work in moles, and 1 mole of phenol is about 94 g (general knowledge).
Common Mistakes
- Waiting for pain before washing — phenol deadens it.
- Using a small splash of water — it needs volume and time.
- Handling crude carbolic oil with bare hands.
- Distilling in a closed system.
Phenol burns without pain and poisons through the skin
Phenol is corrosive, locally anaesthetic and absorbed through skin with systemic toxicity. Wear chemical-resistant gloves, a face shield and an apron, work outdoors, and keep a large volume of water at hand. Flood any contact immediately, remove contaminated clothing and seek medical care. See Protective Gear and Chemical Burns.
What’s Next
- Learn next: Formaldehyde Production — the other feedstock
- Combine with: Synthesis and Molding — putting them together