Freebase (chemistry)

Freebase or free base refers to the standalone neutral, basic form of an amine, as opposed to its water-soluble salt form. The amine is usually an alkaloid natural product. "Free base" is commonly used in chemistry and pharmaceuticals to describe the unprotonated amine form of a compound. The adverb "freebase" and the verb "freebasing" are usually restricted to recreational drug-related contexts.

Most alkaloids are unstable and corrosive in their freebase form, and thus are usually stored as ammonium salts. The charged salt is usually much more soluble than the molecular freebase. Common counterions include chloride, bromide, acetate and oxalate. Because of the ubiquity of chloride salts, formed from the reaction of the amine with hydrochloric acid, these amine derivatives are known as the hydrochlorides. For example, compare the free base hydroxylamine with hydroxylamine hydrochloride.

Preparation

Obtaining a purified free base is often a goal during workup of chemical reactions producing amines. Generally, the amine-containing product is acidified to give the ammonium salt, and extracted with water and an organic solvent such as dichloromethane. The desired ammonium salt dissolves in the aqueous layer, while the impurities (presumably not aqueous soluble) remain in the organic layer.

Adding an appropriate base, the aqueous solution is re-extracted with organic solvent to obtain the free base in the organic layer, leaving simple inorganic salt-impurities behind.

Freebases in recreational drug usage

When used as a verb, it refers to smoking freebase cocaine, crack cocaine, freebase heroin or more rarely freebase PCP. Freebasing also refers to the process of freeing the active ingredients of a drug from its adulterants with which, in the slang term, it has been "cut". Adulterants are various substances which are mixed into drugs as fillers by dealers, thus increasing the amount that they can sell. Adulterants commonly include inositol and baby powder in the case of cocaine, and a wide range of substances in the case of heroin.

Drugs smoked in their freebase form are generally more powerful, and act more rapidly, than their salts.Fact|date=June 2008 This can make freebase drugs even more powerfully addictive than their salt equivalents.Fact|date=June 2008 Some drugs such as methamphetamine, MDMA, and mescaline are strong-smelling, corrosive oily yellow liquids when in base form and so are rarely ingested as bases, instead almost always being encountered as the hydrochloride or sulfate salts.

Freebase heroin

Illegal heroin is sometimes distributed in its freebase form, highly adulterated with fillers. The users then add acid to convert it to its water-soluble salt form to make it injectable. This is typically done by mixing the freebase form of the drug with a commonly available mild acid such as acetic or citric acid, and warming the mixture in a spoon or aluminum foil in order to make an injectable solution. Often the solution is injected hot to add a rush as it is felt travelling through the user's body, although it is far less dangerous to let it cool to more of a warm state.Fact|date=June 2008

Freebase cocaine

As the name implies, "freebase" is the base form of cocaine, as opposed to the salt form of cocaine hydrochloride. Whereas cocaine hydrochloride is extremely soluble in water, cocaine base is insoluble in water and is therefore not suitable for drinking, snorting or injecting. Cocaine hydrochloride is not well-suited for smoking because the temperature at which it vaporizes is very high, and close to the temperature at which it burns; however, freebase cocaine base vaporizes at a low temperature, which makes it suitable for inhalation.

Smoking freebase is preferred by many users because the cocaine is absorbed immediately into blood via the lungs, where it reaches the brain in about five seconds. The rush is much more intense than sniffing the same amount of cocaine nasally, but the effects do not last as long. The peak of the freebase rush is over almost as soon as the user exhales the vaporFact|date=June 2008, but the high typically lasts 5–10 minutes afterwards. What makes freebase a particularly dangerous drug is that users typically don't wait that long for their next hit and will continue to smoke freebase until none is left.Fact|date=June 2008 These effects are similar to those that can be achieved by injecting cocaine hydrochloride, but without the risks associated with intravenous drug use (although there are other serious risks associated with smoking freebase).

Freebase cocaine is produced by first dissolving cocaine hydrochloride in water. Once dissolved in water, cocaine hydrochloride (Coc HCl) dissociates into protonated cocaine ion (CocH⁺) and chloride ion (Cl^-). Any solids that remain in the solution are not cocaine (they are part of the cut) and are removed by filtering. A base, typically ammonia (NH₃) in the case of traditional "freebase" or sodium bicarbonate (baking soda) in the case of crack freebase, is added to the solution. Using ammonia as an example, the following net chemical reaction takes place:

:NH₃ + CocH⁺ + Cl^- → NH₄Cl + Coc

As freebase cocaine (Coc) is insoluble in water, it precipitates and the solution becomes cloudy. To recover the freebase in the "traditional" manner, diethyl ether is added to the solution: Since freebase is highly soluble in ether, a vigorous shaking of the mixture results in the freebase being dissolved in the ether. As ether is practically insoluble in water, it can be siphoned off. The ether is then left to evaporate, leaving behind the nearly pure freebase. Alternatively, the baking soda/freebase solution is simply evaporated until the solution "rocks up"—thereby producing the form commonly known as "crack" or "rock" cocaine.

Since the manufacture of "traditional" freebase involves the use of flammable solvents, it is a dangerous process, particularly since it is often carried out outside a controlled laboratory environment without sufficient safety precautions.

The "traditional" procedure is dangerous because of the hazards of handling diethyl ether: it is extremely flammable, its vapors are heavier than air and can "creep" from an open bottle, and in the presence of oxygen it can form peroxides which can spontaneously combust. It is due both to these dangers and to the relative complexity of the "traditional" ammonia/ether method that the simpler "crack" method with sodium bicarbonate became the norm.

Although freebase cocaine prepared with ammonia and ether is generally purer than freebase cocaine prepared with baking soda but no solvent, the cocaine fumes produced when the product is smoked are approximately equally pure, and the active ingredient ingested is exactly the same. Despite this, for many years "traditional" freebase smokers scorned "crack" freebase smokers—asserting incorrectly that these were fundamentally different drugs.

External links

* [http://www.erowid.org/ask/ask.cgi?ID=2348 what does it mean when something is converted to a freebase?]

* [http://www.cocainehelp.org/mod-subjects-viewpage-pageid-1.html Cocaine-Drug of Illusion]