31. Contributed by
J. KRC, JR.,
Acetoacetanilide 11
AND
W. C. MCCRONE, Armo,ur ~ e s e a r o hrOunaation, Illinois I n s t i t u t e of 'lleotmology, ChicagoI 16, 111.
CHa--C-CHIG-NH-C6Hs
8
Optic Axial Angles (5893 A,; 25" C.). 2V = 74" (cdcd.); 2E = ~ 160' .(on1cd.l. ~ .. . Dispersion. T v. Optical Axial Plane. 010. Sign of Double Refraction. Positive. Acute Biseetrix. y = Moleculm Refraction (R)(5893A.: 25" C.). = 1.618. R (calcd.) = 49.5. R(ab8d.I = 50.4.
8
>:
~
Structural formula for acetoacetanilide
(I.
OOD crystals are obtained from deohol, dioxane, G ethyl acetate, acetone, and benzene solutions (Figure 1). Figure 2 show8 an orthographic projection of typical crystal rater,
a
from solution. Four polymorphs have been observed from fusion (I); however, only the stable modification I w w obtained from solutions with various solvents and varying conditions of orystallieation.
Figure 2. Orthographic Projection of Tvoisal Crvstal of Acetoamtanilide I
FUSION D
Aoetoacecaniiioe snows row poiymorpmr; m r m wuen wysw.ilieed from fusion. If fused completely and allowed to cool m y of these modificstions may crystallize, either spantaneousiy or with a plioation of pressure on the oover g1.m. F o r m I (m.p. 83" C.yand IV grow rapidly as highly birefnngent rods or plates, the latter being transformed almost immediiutely by I from many nuclei. This rapid transformation made it im ssible to deter111 (m.p. mine melting oint of modification IV. Modi!&ion 61" C.) solidi&s spontaneously from a supercooled melt as very low birefringent spherulites (hrst-order ay to yellow). Modification I1 (m.p. 72" C.) seldom eryst&m spontaneously. It can be observed readily, however in the transformation Ill I1 at lower temperatures, cry$alli& into fine ,radiating crystals from manv mints of nucleation. Transformation I11 -P I is raoid
R
A Figure 1. Aoetoaoetanilide A. 6.
C v e t s l s 01 modificetionI from betmeme
( p ~ r d l e Niools) l Fusion p~epaietiond t o r f m g Modihoitions I, 111, and 1%'(cmsacd
Nicole)
-
CRYSTAL MORPFIOWOY Crystal System. Orthorhombic. Form and Habit. Hemimorphio tablets or rods elongated alon c, lying an macropinamid (100) and showing forms ( O l O ) , 10017, 10211, 10411,and (110). Add Ratio. o:bc = 0.573:130.450, Interfacial Angles (Polar). 021 A 021 = 83' 55'; 041 A 031 = 121"50'; 11OA 100 = 29"40'. Cleavage. (100)andslight (0101. X-RAYDIFFRACTION DATA CellDimensions. a = 11.07A.; b = 19.31A.; e = 8.68A. Formula Weights per Cell. 8. Formula. Weight. 177.20. Density. 1.23 (pycnometer); 1.26 (x-ray).
rmall whke upper right section, Ghich is modification 111. LITERATURE CITED
Principal Lines d
(1) KoEer. A,, M i ! m x h i e o e r . Mikrochim. A
d
h . 34, 15-24 (1848).
~ o l r ~ ~ i s n n o ncrvatallo.araphihie sof datsfor thio~8itionshouldbep8nttowalter C. MoCrone. Analytical Section. Armour Research Foundation of Illinois Institute of Teohnoloqy, Chicago. Ill.
Determination of Carbon in Ferrous Alloys SIR: I n the report of the Atlantic City round-table discussion
_.. "..
tho
OP~ICAL PROPERTIES Refractive Indexes (5893 A,; 25' C.). 6 B = 1.603 * 0.002; 'I = 1.697 1 0.002.
-
"l."
...
"notnrminstinn n F Ps-hnn in lbwnnAlln.id2 Y I YI....... I". Y " . . _ . _.I" _"..""I ._.
_-.."J"
IAwir
,._I.. I ..
CHEM., 22,488 (1960)] I note some errom in reporting my portion
1.556
+
of the discussion. ThEi occurs on page 488, seeand column, and third paragraph.
0.002; t5
