Freebase (chemistry)
Encyclopedia
Freebase or free base refers to the pure basic
form of an amine
, as opposed to its salt form. The amine is usually an alkaloid
natural product. Free base is commonly used in organic chemistry
and pharmaceuticals to describe the unprotonated amine form of a compound.
Most alkaloids are unstable in their pure form and exist in ionic salt form. The salts usually exhibit greater water solubility. 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 hydrochloride
s. For example, compare the free base hydroxylamine
(NH2OH) with hydroxylamine hydrochloride (NH3OH+ Cl-).
The term "freebasing" means to convert an ionic form into free base. It can refer to deprotonating
hydrochloride salt
form of cocaine
to free base form. The process provides for same merits of acid-base extraction. The free base is preferred for smoking because the evaporation point of the free base is further apart from the burning point compared to the hydrochloride salt, making the salt form more prone to destruction by pyrolysis
. Some of the active drug is lost in the deprotonation process. Freebasing became popular in the United States
during the 1980s, mainly due to the fear of diseases such as HIV
and viral hepatitis
, since users did not have to share hypodermic needle
s.
"Freebasing" may also describe the use of ammonia in cigarettes, which helps convert bound nicotine molecules in tobacco smoke into free nicotine molecules, therefore, boosting the effect of the nicotine on the smoker.
Base (chemistry)
For the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...
form of an amine
Amine
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...
, as opposed to its salt form. The amine is usually an alkaloid
Alkaloid
Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...
natural product. Free base is commonly used in organic chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
and pharmaceuticals to describe the unprotonated amine form of a compound.
Most alkaloids are unstable in their pure form and exist in ionic salt form. The salts usually exhibit greater water solubility. Common counterions include chloride
Chloride
The chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
, bromide
Bromide
A bromide is a chemical compound containing bromide ion, that is bromine atom with effective charge of −1. The class name can include ionic compounds such as caesium bromide or covalent compounds such as sulfur dibromide.-Natural occurrence:...
, acetate
Acetate
An acetate is a derivative of acetic acid. This term includes salts and esters, as well as the anion found in solution. Most of the approximately 5 billion kilograms of acetic acid produced annually in industry are used in the production of acetates, which usually take the form of polymers. In...
and oxalate
Oxalate
Oxalate , is the dianion with formula C2O42− also written 22−. Either name is often used for derivatives, such as disodium oxalate, 2C2O42−, or an ester of oxalic acid Oxalate (IUPAC: ethanedioate), is the dianion with formula C2O42− also written (COO)22−. Either...
. Because of the ubiquity of chloride salts, formed from the reaction of the amine with hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
, these amine derivatives are known as the hydrochloride
Hydrochloride
In chemistry, hydrochlorides are salts resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic base . This is also known as muriate, derived from hydrochloric acid's other name: muriatic acid....
s. For example, compare the free base hydroxylamine
Hydroxylamine
Hydroxylamine is an inorganic compound with the formula NH2OH. The pure material is a white, unstable crystalline, hygroscopic compound. However, hydroxylamine is almost always provided and used as an aqueous solution. It is used to prepare oximes, an important functional group. It is also an...
(NH2OH) with hydroxylamine hydrochloride (NH3OH+ Cl-).
The term "freebasing" means to convert an ionic form into free base. It can refer to deprotonating
Deprotonation
Deprotonation is the removal of a proton from a molecule, forming the conjugate base.The relative ability of a molecule to give up a proton is measured by its pKa value. A low pKa value indicates that the compound is acidic and will easily give up its proton to a base...
hydrochloride salt
Hydrochloride
In chemistry, hydrochlorides are salts resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic base . This is also known as muriate, derived from hydrochloric acid's other name: muriatic acid....
form of cocaine
Cocaine
Cocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system, an appetite suppressant, and a topical anesthetic...
to free base form. The process provides for same merits of acid-base extraction. The free base is preferred for smoking because the evaporation point of the free base is further apart from the burning point compared to the hydrochloride salt, making the salt form more prone to destruction by pyrolysis
Pyrolysis
Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures without the participation of oxygen. It involves the simultaneous change of chemical composition and physical phase, and is irreversible...
. Some of the active drug is lost in the deprotonation process. Freebasing became popular in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
during the 1980s, mainly due to the fear of diseases such as HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
and viral hepatitis
Viral hepatitis
Viral hepatitis is liver inflammation due to a viral infection. It may present in acute or chronic forms. The most common causes of viral hepatitis are the five unrelated hepatotropic viruses Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, and Hepatitis E...
, since users did not have to share hypodermic needle
Hypodermic needle
A hypodermic needle is a hollow needle commonly used with a syringe to inject substances into the body or extract fluids from it...
s.
"Freebasing" may also describe the use of ammonia in cigarettes, which helps convert bound nicotine molecules in tobacco smoke into free nicotine molecules, therefore, boosting the effect of the nicotine on the smoker.