CRYSTALLOGRAPHIC DATA-31. Acetoaccentanilide I (Acetoaccetic

of crystallographic data for this section should besent to Wal- ter C. McCrone, Analytical Section, Armour Research Foundation of Illinois. Institute ...
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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)

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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

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OP~ICAL PROPERTIES Refractive Indexes (5893 A,; 25' C.). 6 B = 1.603 * 0.002; 'I = 1.697 1 0.002.

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...

"notnrminstinn n F Ps-hnn in lbwnnAlln.id2 Y I YI....... I". Y " . . _ . _.I" _"..""I ._.

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IAwir

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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