page_title: Crack cocaine
section_title: Synthesis
hierarchical_section_title: Crack cocaine / Physical and chemical properties / Synthesis
caption_attribution_description: English: Cooking Crack in a Spoon with Sodium Bicarbonate
context_page_description: Crack cocaine, also known simply as crack or rock, is a free base form of cocaine that can be smoked. Crack offers a short, intense high to smokers. The Manual of Adolescent Substance Abuse Treatment calls it the most addictive form of cocaine. Crack first saw widespread use as a recreational drug in primarily impoverished neighborhoods in New York City, Philadelphia, Baltimore, Washington, D.C., Los Angeles, and Miami in late 1984 and 1985; its rapid increase in use and availability is sometimes termed as the "crack epidemic".
context_section_description: Sodium bicarbonate (NaHCO₃, common baking soda) is a base used in preparation of crack, although other weak bases may substitute for it. The net reaction when using sodium bicarbonate is
  Coc-H⁺Cl⁻ + NaHCO₃ → Coc + H₂O + CO₂ + NaCl
  With ammonium bicarbonate:
  Coc-H⁺Cl⁻ + NH₄HCO₃ → Coc + NH₄Cl + CO₂ + H₂O
  With ammonium carbonate:
  2(Coc-H⁺Cl⁻) + (NH₄)₂CO₃ → 2 Coc + 2 NH₄Cl + CO₂ + H₂O
  Crack cocaine is frequently purchased already in rock form, although it is not uncommon for some users to "wash up" or "cook" powder cocaine into crack themselves. This process is frequently done with baking soda (sodium bicarbonate), water, and a spoon. Once mixed and heated, the bicarbonate reacts with the hydrochloride of the powder cocaine, forming free base cocaine and carbonic acid (H₂CO₃) in a reversible acid-base reaction. The heating accelerates the degradation of carbonic acid into carbon dioxide (CO₂) and water. Loss of CO₂ prevents the reaction from reversing back to cocaine hydrochloride. Free base cocaine separates as an oily layer, floating on the top of the now leftover aqueous phase. It is at this point that the oil is picked up rapidly, usually with a pin or long thin object. This pulls the oil up and spins it, allowing air to set and dry the oil, and allows the maker to roll the oil into the rock-like shape.
  Crack vaporizes near temperature 90 °C (194 °F), much lower than the cocaine hydrochloride melting point of 190 °C (374 °F). Whereas cocaine hydrochloride cannot be smoked (burns with no effect), crack cocaine when smoked allows for quick absorption into the blood stream, and reaches the brain in eight seconds. 
  Crack cocaine can also be injected intravenously with the same effect as powder cocaine. However, whereas powder cocaine dissolves in water, crack must be dissolved in an acidic solution such as lemon juice (containing citric acid) or white vinegar (containing acetic acid), a process that effectively reverses the original conversion of powder cocaine to crack. Harm reduction and public health agencies may distribute packets of citric acid or ascorbic acid (Vitamin C) for this purpose.
caption: A close up of the "cooking" process that creates crack.
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