1,4-NAPHTHOQUINONE

1,4-Naphthoquinone is the parent structure of the family of 1,4-naphthoquinones, in which the oxo groups of the quinone moiety are at positions 1 and 4 of the naphthalene ring. Derivatives have pharmacological properties. 
1,4-Naphthoquinone derives from a hydride of a naphthalene.

CAS:    130-15-4
MF:    C10H6O2
MW:    158.15
EINECS:    204-977-6

Synonyms: 1,4-Naftochinon;1,4-Naphthaquinone;1,4-Naphthylquinone;Dapoxetine Impurity R;нафтахинон, нафталин-1,4-дион, α-Naphthoquinone, п-нафтахинон, 1,4-Naphthoquinone, Naphthalene-1,4-dion;1,4-napthaquinone,Naphthoquinone;1,4-naphtoquinone;A-NAPHTHOQUINONE

1,4-Naphthoquinone or para-naphthoquinone is a quinone derived from naphthalene. 
1,4-Naphthoquinone forms volatile yellow triclinic crystals and has a sharp odor similar to benzoquinone. 
1,4-Naphthoquinone is almost insoluble in cold water, slightly soluble in petroleum ether, and more soluble in polar organic solvents. 
In alkaline solutions 1,4-Naphthoquinone produces a reddish-brown color.
Natural vitamin K is a derivative of 1,4-naphthoquinone. 
1,4-Naphthoquinone is a planar molecule with one aromatic ring fused to a quinone subunit.
1,4-Naphthoquinone itself has some vitamin K activity.
1,4-Naphthoquinone is an isomer of 1,2-naphthoquinone.
1,4-Naphthoquinone is a powder used in chemical manufacturing, primarily in polymerization processes. 
1,4-Naphthoquinone acts as a hardener, enhancing the strength and durability of polyesters and other polymers. 
Known for its excellent strength and high durability, 1,4-Naphthoquinone plays a crucial role in improving the performance of plastics and elastomers.
1,4-Naphthoquinone is an organic compound used as a starting material in the synthesis of various pharmaceuticals. 
1,4-Naphthoquinone's quinone structure makes it a versatile intermediate, contributing to the formation of complex pharmaceutical agents.

1,4-Naphthoquinone Chemical Properties
Melting point: 119-122 °C(lit.)
Boiling point: 243.22°C (rough estimate)
Density: 1,42 g/cm3
Vapor pressure: <1 hPa (50 °C)
Refractive index: 1.5300 (estimate)
Fp: 141 °C
Storage temp.: Store below +30°C.
Solubility: 0.09g/l
Form: Powder
Color: Khaki
PH: 6.1 (10g/l, H2O, 20℃)
Water Solubility: insoluble
Merck: 14,6395
BRN: 878524
Stability: Stable. Incompatible with strong reducing agents, strong oxidizing agents.
InChIKey: FRASJONUBLZVQX-UHFFFAOYSA-N
LogP: 1.71-1.77 at 25℃
CAS DataBase Reference: 130-15-4(CAS DataBase Reference)
NIST Chemistry Reference: 1,4-Naphthoquinone(130-15-4)
EPA Substance Registry System: 1,4-Naphthoquinone (130-15-4)

1,4-Naphthoquinone is a yellow to greenish yellow crystalline solid that has pungent odor like benzoquinone. 
1,4-Naphthoquinone is slightly soluble in water, soluble in ether, chloroform, benzene, glacial acetic acid.
In alkaline solutions 1,4-Naphthoquinone produces a reddish-brown color.

Reactions
1,4-Naphthoquinone acts as strong dienophile in Diels-Alder reaction.
1,4-Naphthoquinone's adduct with 1,3-butadiene can be prepared by two methods: 1) long (45 days) exposure of naphthoquinone in neat liquid butadiene taken in huge excess at room temperature in a thick-wall glass tube or 2) fast catalyzed cycloaddition at low temperature in the presence of 1 equivalent of tin(IV) chloride.

Uses    
1,4-Naphthoquinone is used as a strong dienophile in Diels-Alder reaction. 
1,4-Naphthoquinone is also used as a precursor to anthroquinone and 5-nitro-1,4-naphthalenedione, which finds application in the preparation of aminoanthroquinone and is also used as a dye precursor. 
1,4-Naphthoquinone is a basic component of Vitamin K.
1,4-Naphthoquinone is an important organic intermediate compound, it is the chemical intermediate of fungicide dichlone and dithianon, and also the by-product of anthraquinone synthesis. 
1,4-Naphthoquinone can be used as polymerisation regulator of rubber and polyester resin, synthesis of dyestuffs and drugs, algaecide, corrosion inhibitor, stabiliser of transformer oil, etc.
1,4-Naphthoquinone is mainly used as a precursor to anthraquinone by reaction with butadiene followed by oxidation. 
Nitration gives 5-nitro-1,4-naphthalenedione, precursor to an aminoanthroquinone that is used as a dye precursor.

Synthesis
1,4-Naphthoquinone is prepared by reacting naphthalene with molecular oxygen in a gaseous phase in the presence of a catalyst containing vanadium.
Prior to reacting the naphthalene with oxygen, the catalyst is pre-treated with molecular oxygen at 300° to 400° C in the absence of organic compounds and immediately thereafter a gas mixture containing naphthalene and molecular oxygen is passed over the pretreated catalyst at temperatures in the range of 300° to 400° C. 
The catalyst pre-treatment can be carried out in the presence of water vapor and the subsequent reaction of naphthalene with molecular oxygen can also be carried out in the presence of water vapor.

Preparation
The industrial synthesis involves aerobic oxidation of naphthalene over a vanadium oxide catalyst:

C10H8 + 3/2 O2 → C10H6O2 + H2O
In the laboratory, naphthoquinone can be produced by the oxidation of a variety of naphthalene compounds. 
An inexpensive route involves oxidation of naphthalene with chromium trioxide.

Reactivity Profile    
1,4-Naphthoquinone may react with many acids and bases liberating heat and flammable gases (e.g., H2). 
The heat may be sufficient to start a fire in the unreacted portion of the ketone. 
May react with reducing agents such as hydrides, alkali metals, and nitrides to produce flammable gas (H2) and heat. 
Incompatible with isocyanates, aldehydes, cyanides, peroxides, and anhydrides. 
May react violently with aldehydes, HNO3, HNO3 + H2O2, and HClO4.