Studies of Thermal Transformations in Organic Crystals

221 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.This research deals with three types of thermal solid-state transformations: (I) a physical transformation (or phase change); (II) a solid-state Beckmann-Chapman rearrangement; and (III) a solid-state Mumm rearrangement. During the course of other solid-state research, two polymorphs of benz-2,4-dinitroanilide (1) were discovered. A phase change from 1A to 1B occurred at 130(DEGREES) with sharp frontal migration in the long direction of the crystals. An investigation of the crystal structures of both forms was completed. Crystals of 1A were monoclinic, space group P2(,1/c) and z = 4. a = 6.810(2), b = 11.125(4), c = 17.178(5) (ANGSTROM), (beta) = 109.38(2)(DEGREES). Crystals of 1B were triclinic, space group P(')1 and z = 2. a = 7.649(2), b = 11.983(3), c = 7.414(2) (ANGSTROM), (alpha) = 101.82(2), (beta) = 110.57(2), (gamma) = 84.42(2)(DEGREES).The solid-state Beckmann-Chapman rearrangement of oxime picryl ethers was further investigated using the benzophenone oxime picryl ether (3) - N-picrylbenzanilide (4) system. Crystals of 3 were synthesized and laser Raman spectra were taken. The phonon spectra of the rearrangement indicate that the rearrangement may have an initial homogeneous phase. X-ray crystallographic determinations of the structures of both 3 and 4 were accomplished. Crystals of 3 were monoclinic, space group C(,2/c) and z = 8. a = 11.717(5), b = 12.870(7), c = 25.55(1) (ANGSTROM), (beta) = 90.15(4)(DEGREES). Crystals of 4 were monoclinic, space group P2(,1/c) and z = 4. a = 11.623(2), b = 6.139(2), c = 26.359(8) (ANGSTROM), (beta) = 101.02(2)(DEGREES).The Mumm rearrangement of isoimides to dibenzoylimides was found to occur in the solid-state. Two isoimides, N-(2,4-dinitrophenyl) benzimidoyl 4-methoxybenzoate (methoxy-6) and N-(2,4-dinitrophenyl) benzimidoyl p-toluate (methyl-6), were synthesized. Methoxy-6 rearranged in the solid-state at 113(DEGREES) to N-(2,4-dinitrophenyl) benzoyl-4-methoxybenzoylimide (methoxy-7). At 100(DEGREES) methyl-6 underwent a solid-state rearrangement to N-(2,4-dinitrophenyl) benzoyl-p-tolylimide (methyl-7). It was found from X-ray crystallographic investigations that crystals of methoxy-6 and methyl-6 were essentually isostructural. They were both triclinic, space group P(')1 and z = 2. For methoxy-6, a = 11.848(6), b = 11.358(4), c = 7.824(4) (ANGSTROM), (alpha) = 87.92(3), (beta) = 106.29(4), (gamma) = 104.58(3)(DEGREES). For methyl-6, a = 11.610(3), b = 11.233(2), c = 8.026(2) (ANGSTROM), (alpha) = 89.08(2), (beta) = 107.55(2), (gamma) = 99.60(2)(DEGREES).U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD