What are the chemical preparation of iron oxide yellow?

What are the chemical preparation of iron oxide yellow, detailed below.

Aromatic nitro compounds of oxidation also produces aromatic amino. The reaction equation is as follows:

Fe+H2O+R-NO2→Fe2O3· H2O+R-NH2

Reaction conditions are as follows: include 560 parts water in the reactor, 36.5, 32% hydrochloride, 160 iron and 10 aluminium powders. 16~24h added to the reaction vessel 1460 with 253 parts of 5-Nitro-naphthalene sulfonic acid and 8-Nitro-naphthalene sulfonic acid with aqueous, aqueous solution of naphthalenesulfonic acid pH values of 6, temperature 80~85℃. Reaction Kettle within temperature in 95~100℃, pH value for 6~6.5, this conditions Xia reaction 2H, joined 8 copies 25% ammonia, further reaction 4H, filter, with 560 copies washing filter cake three times, will washing Hou of filter cake and 1000 copies water mixed, in 95~100℃ heating, joined 45 copies 32% hydrochloride, mixing 2H, filter, will filter cake washing to no acid, dry can have 160 copies iron oxide yellow pigment, while get amino naphthalene sulfonic acid, received rate 96%.

Sulfuric acid reacts with iron oxidation of ferrous sulfate ferrous sulfate, adding sodium hydroxide and into the air oxidation of nucleus, then add in the nucleus suspensions of ferrous sulfate and iron, oxidation of heat into the air, filter, rinse, dry, crushed iron oxide yellow.