Dictionary of Chemistry [6th Ed.]

benzoyl chloride 64

b

benzoyl chlorideSee benzenecar-

bonyl chloride.

benzoylecgonine(BZ)A primary

metabolite of cocaine, used in drug

testing. It can be detected in the

urine up to 48 hours after taking co-

caine. BZ is tested for by immunoas-

say or by gas chromatography/mass

spectrometry.

benzoyl group See benzenecar-

bonyl group.

benzpyrene A pale yellow solid,

C 20 H 12 , m.p. 179°C, whose molecules

consist ofÜve fused benzene rings. It

occurs in tars from coal and tobacco

smoke and is a *carcinogen.

benzvaleneA valence isomer of

benzene, C 6 H 6 , with a bridged struc-

ture.

benzyl alcoholSee phenyl-

methanol.

benzylamine(α-aminotoluene,

phenylmethylamine)A colourless liq-

uid, C 6 H 5 CH 2 NH 2 ; r.d. 0.981; b.p.

185 °C. It behaves in the same way as

primary aliphatic amines.

benzyne(1,2-didehydrobenzene) A

highly reactive short-lived com-

pound, C 6 H 4 , having a hexagonal

ring of carbon atoms containing two

double bonds and one triple bond.

Benzyne, which is the simplest exam-

ple of an *aryne, is thought to be an

intermediate in a number of reac-

tions.

CH

CH

C

H

C

H

Benzyne

Bergius, Friedrich Karl Rudolf

(1884–1949) German organic

chemist. While working with Fritz

*Haber in Karlsruhe, he become in-

terested in reactions at high pres-

sures. In 1912 he devised an

industrial process for making light

hydrocarbons by the high-pressure

hydrogenation of coal or heavy oil.

The work earned him a share of the

1931 Nobel Prize for chemistry with

Carl Bosch (1874–1940). The Bergius

process proved important for supply-

ing petrol for the German war effort

in World War II.

Bergius process A process for

making hydrocarbon mixtures (for

fuels) from coal by heating powdered

coal mixed with tar and iron(III)

oxide catalyst at 450°C under hydro-

gen at a pressure of about 200 atmos-

pheres. In later developments of the

process, the coal was suspended in

liquid hydrocarbons and other cata-

lysts were used. The process was de-

veloped by Friedrich *Bergius during

World War I as a source of motor fuel.

berkeliumSymbol Bk. A radio-

active metallic transuranic element

belonging to the *actinoids; a.n. 97;

mass number of the most stable iso-

tope 247 (half-life 1.4 × 103 years); r.d.

(calculated) 14. There are eight

known isotopes. It wasÜrst produced

by G. T. Seborg and associates in

1949 by bombarding americium–241

with alpha particles.

A

• Information from the WebElements site

Berry mechanismA mechanism

by which ligands in trigonal bipyra-

midal complexes can interchange be-

tween axial and equatorial positions.

It involves intermediate formation of

a square pyramidal conformation. It

is also known as the Berry pseudo-

rotation.

Berthelot, Marcellin (Pierre Eu-

gène)(1827–1907) French chemist

who pioneered organic synthesis,

producing many organic compounds