Primary

Name:
Primary
Detailed information:
(1) In reference to monohydric alcohols, amines, and a few related compounds, this term, together with secondary and tertiary, describes the molecular structure of isomeric or chemically similar individuals. Monohydric alcohols are based on the methanol group
in which three of the bonds of the methanol carbon may be attached either to hydrogen atoms or alkyl groups. A primary alcohol has one alkyl group and two hydrogens,

except methanol, in which all three bonds are to hydrogen atoms. A secondary alcohol has two alkyl groups and one hydrogen, e.g.,

A tertiary alcohol has three alkyl groups, e.g.,

The three types can be readily identified by the number of hydrogen atoms attached to the central (methanol) carbon atom: if it is two or more, the alcohol is primary; if one, it is secondary; and if zero, it is tertiary. For example, CH₃CH₂OH is primary; (CH₃)₂CH₂OH is secondary; (CH₃)₃COH is tertiary. Primary, secondary, and tertiary amines are formed from ammonia (NH₃) when one, two, or three hydrogen atoms, respectively, are replaced by alkyl groups.
These terms are also used to name salts of orthophosphoric acid (H₃PO₄) in which one, two, or three of the hydrogen atoms have been replaced by metal or radicals: NaH₂PO₄ is primary sodium phosphate, Na₂HPO₄ is secondary sodium phosphate. The same system of names is used for salts of other acids containing three replaceable hydrogen atoms.(2) A type of battery that is irreversible in respect to power output; a voltaic cell. A secondary battery (storage battery) is reversible and can be recharged.(3) In the terminology of minerals, primary (in the case of metals) refers to direct production from the ore; in the case of petroleum it refers to production from wells by direct means. This meaning contrasts with the term secondary that is used to denote recovery of metal from scrap and, for petroleum, recovery by means of special techniques such as flooding and hydraulic pressure.