6 BULLETIN 1390, U. S. DEPARTMENT OF AGRICULTURE 
ORANGE I 
Orange I (Ci6Hi:N,0,SNa), a monazo dye (41, 42, 60, 74, 75), is 
made by coupling diazotized para-sulphanilic acid with a-naphthol. 
Sufficiently pure para-sulphanilic acid is readily obtainable. The 
purity of the a-naphthol used, however, is of the utmost im- 
portance. The percentage of 8-naphthol present in this intermediate 
should be as low as practicable, as 6-naphthol coupled with para- 
sulphanilic acid produces orange II, which is so toxic that it is ex- 
tremely objectionable and is tolerated only in small quantity in the 
final product if the orange I is to be used for coloring foods or bever- 
ages. It is safer to use a-naphthol made from a-nitronaphthalene 
than that made from a-naphthalene-sulphonic acid. Even when 
a-naphthol from a-nitronaphthalene is used, care must be taken to 
provide that the a-naphthylamine formed in the process be transformed 
as completely as possible into the naphthol. To the extent that this 
is incomplete the objectionable insoluble coloring matter sulpho- 
benzeneazo-a-naphthylamine will be present in the final product. 
Because calcium forms an insoluble salt with orange I, only lime- 
free water should be used as a solvent in the final stages of the process 
of manufacture and in the purification of the dye, if it is to be of certi- 
fied grade. It has been shown that even small quantities of the cal- 
cium salt cause the solution of the dye to “set” to a stiff, opaque, 
jellylike mass. 
Foundation and supplemental affidavits (70) for this dye should 
contain analytical data on the determinations listed in Table 4, 
which also enumerates the methods of analysis and shows the purity 
specifications. 
TABLE 4.—Specifications for orange I 
acre et ue 
olerance inimum ethod of 
Component (ratio to pure| tolerance analysis 
coal-tar dye) 
Per cent Per cent Page 
IVEDISHIEO meta tec ee ete ee i ee re oe oe LOO ets |Erroneee ee 14. 
Insoluble matter: 
Ota = 8 EL a IE the 2 ee ee 5 en ete ea es 15. 
INonyolatile: 2-22-24. 222ee es SS Sie Se a eee ce cece D gine i toa pe heed £5. 
Sodimmrenloride: 2-222 2-5-3 Ae ee ee A ae et 3: OR to) | Sse Beta 15, 16 
Sodiunrsulphate-. 2. sv act ase sire Bor as as eee eee. Oe mf soeat es oes iV és 
Siiphated ashe $25 = 2. ae © ee ee ee eee ee (0) Reet Peeve ee 18. 
Sodium in color! 345245 cos ae ee eae ee ee “Theoretical sew oe 18. 
Heavy metals 3. = we hed Se See be Po San See Ree SS 010 ee eee 19. 
Malem te Ste te 220 = oes een Cae oe en 2, J ees Tae 0305: ~sie/2ate-22 2-85 19. 
IViaonesitina £40)" hooey at OL AOC Fe os See eee ot Soo # ee es a eee 19. 
VATETTAUTATUITYY so Se Bs hel he a RO Ee ec a eee 5 — aon trate oh wel 19. 
NOT es een see hk ae ig a BP ee be RES ai eS ee eee oy Rie eeegererree es te 19. 
HATSOMIC: AS “ASa a6 2 2 Seed a aesks coe <i Son Ass woe SER Shes 00014) =. 2222528 22, 23. 
Ether extractives: 
Weutrals 23 joes bak Cen oe Bn er a ee ee (Dyes t a) | see ee 23 
Al alin gs. Soe 8 atte) he oS SARE Sh S ROwls ie Bares (Die -- > See eeet ee 23 ‘ 
NCIC 25.22 Sea oe Seth Sa we) ek eg en cere (1) if pl eee eS 24 
Tots ates 2 we fern Pe Ne ei BUS | ae oe ess 24. 
Silphuriin Color: <4. 5-= sss sooth tn ee eo te eee Theoretieal.-|22222-22-=5 24. 
Color acid ss) ~ arcs ie le anu eid a ee he re he | oe oe ee 76.8 | 25. 
Pure codl-tar dye ts ee et ks ore ea ae ee en 82.0 | 26. 
Subsidiary dyes(as’orange TD). 2 ee ee 5904 * «2 eens 33. 
_ ! Although no limit is here defined, a statement of the percentage found by analysis must be incorporated 
in the foundation and supplemental affidavits (70). 
. Orange I, a reddish-brown powder, dissolves in water to form an 
orange-red solution. Its alcoholic solution is orange. The addition 
: 
