cinnamic acid --> benzaldehydepotassium dichromate, diluted H2SO4
justus liebigs ann chem, 1839 31, 271; simon
cinnamic acid --> benzaldehydewater, hydrogen peroxide, copper sulfate, 60C
bei einwirkung auf das natrium-salz
further products: carbon dioxide, formic acid, acetic acid
biochem j, 1935 29, 1877; jones, smedley-maclean
4-methoxycinnamic acid --> anisaldehydeKMnO4 oxidation, yield 94%
synthesis, 2001 11, 1645-1648
"heterogeneous permanganate oxidation of styrene and cinnamic acid derivatives:
a simple and effective method for the preparation of benzaldehydes"
sheng lai, donald g. lee
abstract: styrene and cinnamic acid derivatives yield correspondingly substituted
benzaldehydes when oxidized by permanganate under heterogeneous conditions.
reaction of terminal aliphatic alkenes under similar conditions gives discouragingly
low yields; however, ketones and ketols are obtained in very good yields from the
oxidation of 2,2-disubstituted and trisubstituted alkenes, respectively. alumina and
amberlite IR-120 can be used as solid supports in these reactions with equally
good results.
https://www.thevespiary.org/rhodium/Rhodium/chemistry/benzaldehydes.kmno4.html
sinapic acid --> syringaldehydeautoclaving
journal of the american oil chemists' society, 1999 76(4), 433-441
"structural changes of sinapic acid and sinapine bisulfate during autoclaving"
with respect to the development of colored substances"
r cai, s d arntfield, j l charlton
abstract: structural changes in sinapic acid during autoclaving were studied using spectral
analysis, thin-layer chromatography, high-performance liquid chromatography, nuclear
magnetic resonance (NMR), and mass spectroscopy. color properties of sinapic acid and
its derivatives were studied by determining the transmittance spectrum, calculating the
commission internationale de l'eclairage 1931 tristimulus values and converting to hunter l
a b values. it was found that the colorless sinapic acid aqueous solution (100 µg/mL) turned
yellow after 15 min in an autoclave at 121°C and 0.1 MPa. filtering the yellow aqueous
solution through a 0.45-µm filter removed a brown solid consisting of at least three
undetermined colored substances and left a yellow liquid. a newly developed yellow
substance, syringaldehyde, was identified in the liquid phase by comparing the NMR and
mass spectra of the unknown with those of authentic syringaldehyde. thomasidioic acid
was also found in the liquid phase. under the same autoclaving conditions, sinapine
bisulfate showed no evidence of any structural or color changes.
catalysed degradation of aqueous solutions of cinnamic acids
in the presence of TiO2 and UV radiation:
journal of environmental science and health part a- toxic/hazardous
substances & environmental engineering, 2001 36(5), 599-612
"PHOTOCATALYTIC DEGRADATION OF TRANS-CINNAMIC,
DIHYDROCINNAMIC, TRANS-CAFFEIC, AND DIHYDROCAFFEIC
ACIDS AND CHARACTERIZATION OF THE PRODUCTS"
Susan M. Grimes, Lina K. Mehta, Helen C. Ngwang
abstract: Catalysed degradation of aqueous solutions of cinnamic 1,
dihydrocinnamic 2, dihydrocaffeic 3 and trans-caffeic 4 acids in the presence of
(TiO2) and UV radiation and the products identified by HPLC, and after treatment
with diazomethane by GC-MS have been studied. A pH range of 3 to 11 was used.
The four acids, in the presence of TiO2 in the dark, underwent little degradation.
Extended irradiation of all the acids in the presence of TiO2 produced complete
degradation as shown by TOC measurements. Initially the volume of carbon
dioxide produced rose steadily to a constant value.
journal of environmental science and health part a- toxic/hazardous
substances & environmental engineering, 2001 36(10), 1891-1904
"CHEMICAL KINETICS OF THE PHOTOCATALYTIC DEGRADATION
OF TRANS-CINNAMIC, DIHYDROCINNAMIC, TRANS-CAFFEIC,
AND DIHYDROCAFFEIC ACIDS"
Susan M. Grimes, Lina K. Mehta, Helen C. Ngwang
abstract: Quantitative studies of the catalysed degradation of aqueous solutions
of cinnamic 1, dihydrocinnamic 2, trans-caffeic 3 and dihydrocaffeic 4 acids in
the presence of TiO2 and UV radiation at pH 3 and 10 are reported. The phenolic
and aliphatic unsaturated groups in caffeic acid 3 caused it to be adsorbed more
strongly than the phenolic saturated acid 4, and these two acids were much more
strongly adsorbed than cinnamic and hydrocinnamic acids. The kinetics of the
degradation of each acid has been studied at pH 3 and 10. TIC analysis showed
complete mineralisation of the acids after 9 h.
j chem soc perkin trans 2, 2001 (5), 793-797
"the reactions of ozone with cinnamic acids:
formation and decay of 2-hydroperoxy-2-hydroxyacetic acid"
Achim Leitzke , Erika Reisz , Roman Flyunt and Clemens von Sonntag
abstract: In aqueous solution, ozone reacts with 4-methoxycinnamate,
cinnamate and 4-nitrocinnamate with rate constants of 6.8 × 105, 3.8 × 105 and
1.2 × 105 dm3 mol-1 s-1, respectively. The corresponding acids react somewhat
more slowly. In product studies, material balance with respect to ozone
consumption has been obtained. In the case of cinnamic acid and its 4-methoxy
derivative, glyoxylic acid, H2O2 and the corresponding benzaldehydes are formed.
In contrast, 4-nitrocinnamic acid affords, besides a full yield of
4-nitrobenzaldehyde, 70% glyoxylic acid and 30% formic acid, while the H2O2
yield is also reduced to 70%. These results can be explained if in the latter case
the Criegee intermediate decomposes not only into glyoxylic acid and
1-hydroperoxy-1-phenylmethanol (which rapidly releases H2O2 yielding
4-nitrobenzaldehyde, k > 0.5 s-1), but also, to an extent of 30%, into
4-nitrobenzaldehyde and 2-hydroperoxy-2-hydroxyacetic acid. This product has
been produced independently by ozonating fumaric acid and has been shown
to decompose rapidly (k > 1 s-1) into formic acid and CO2. The reaction of H2O2
with the free carbonyl form of glyoxylic acid, present at 1.8% in equilibrium with
its hydrate, is comparatively slow (k = 0.3 dm3 mol-1 s-1, based on total glyoxylic
acid concentration). The reaction of the stronger nucleophile HO2-, present in basic
solutions, is considerably faster (k = 1700 dm3 mol-1 s-1). Thus, in the cinnamate
system, the substituents markedly influence the fate of the Criegee intermediate,
although they have only a small influence on the rate of the ozone reaction.