3base
(Newbee) 06-04-02 18:49 No 317544 |
benzaldehydes via cleavage of styrenes | Bookmark | ||||||
this thread is dedicated to the preparation of benzaldehydes via the cleavage of styrene derivatives. depending on the cleavage reaction, the corresponding benzoic acids are often byproducts or in several cases even main products. see Post 317536 (3base: "benzaldehydes from benzoic acids", Chemistry Discourse) for suggestions how to convert benzoic acid derivatives to the corresponding benzaldehydes. |
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3base (Newbee) 06-04-02 18:51 No 317545 |
piperonal from isosafrole (Rated as: excellent) |
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isosafrole --> piperonal ozone, yield 96% tetrahedron letters, 1966 36, 4273-4278; pappas et al chemical abstracts 1966 65, 16890g isosafrole --> piperonal oxidation, K2Cr2O7 and H2S04, yield 47% j chem ind tokyo, 1920 23, 56-79; nagai chemical abstracts, 1920 14, 2839 isosafrole --> piperonylic acid potassium permanganate byproduct: piperonal(yield 8%) j chem ind tokyo, 1920 23, 56-79; nagai chemical abstracts, 1920 14, 2839 isosafrole --> piperonal J Chm Ind Toky 23, 56+151+342 (1920) isosafrole --> piperonal Chem. Trade J. and Chem. Engr. 359 (1926) |
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3base (Newbee) 06-04-02 18:57 No 317548 |
vanillin from 3-methoxy-4-hydroxy-propenylbenzene (Rated as: excellent) |
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3-methoxy-4-hydroxy-propenylbenzene --> vanillin H2O2, tert-butyl alcohol / tert-pentyl alcohol, CrO3 / V2O5 Patent US2437648; 1943; research corp Patent US2402566; 1942; research corp Patent US2414385; 1942; research corp j amer chem soc, 1937 59, 2342; milas 3-methoxy-4-hydroxy-propenylbenzene --> vanillin aqueous H2O2, sulfanilic acid, peroxidase-substance biokhimiya (moscow), 1942 7, 109 111; manskaja, emeljanowa chem abstr, 1943, 4525 3-methoxy-4-hydroxy-propenylbenzene --> vanillin ozone j soc chem ind london, 1922 41, 70 R.; anonymus helv chim acta, 1925 8, 407; briner, v tscharner, paillard helv chim acta, 1924 7, 71; briner, patry, de luserna 3-methoxy-4-hydroxy-propenylbenzene --> vanillin aqueous alkali, elektrolytische oxydation an Pt-, Fe- oder PbO2-anoden trans am elektroch soc, 42, 276 280; lowy, moore chem zentralbl, 1923 94 III, 1516; lowy, moore 3-methoxy-4-hydroxy-propenylbenzene --> vanillin aqueous alkali, 0-12C, elektrolytische oxydation an PbO2-anoden helv chim acta, 1925 8, 333; fichter, christen 3-methoxy-4-hydroxy-propenylbenzene --> vanillin oxygen, glacial acetic acid chem ber, 1915 48, 40; harries, haarmann 3-methoxy-4-hydroxy-propenylbenzene --> vanillin air, acetic acid, 50-60C, irradiation mit ultraviolettem licht Patent DE224071; genthe & co fortschr teerfarbenfabr verw industriezweige, 9, 1130; genthe & co 3-methoxy-4-hydroxy-propenylbenzene --> vanillin ozone, glacial acetic acid ann chim (paris), 1898 <7>13, 123; otto chem ber, 1915 48, 232; witt chem ber, 1915 48, 40; harries, haarmann Patent DE97620; otto, verley fortschr teerfarbenfabr verw industriezweige, 4, 1280; otto, verley 3-methoxy-4-hydroxy-propenylbenzene --> vanillin ozone, acetic acid ester man reduziert das entstandene ozonid in aether mit zink und eisessig chem ber, 1915 48, 40; harries, haarmann 3-methoxy-4-hydroxy-propenylbenzene --> vanillin air, durch ueberleiten des dampfes ueber eine gluehende platinspirale c r hebd seances acad sci, 1901 133, 822; trillat bull soc chim fr, 1903 <3>29, 41; trillat 3-methoxy-4-hydroxy-propenylbenzene --> vanillin alkali chlorate, osmium tetroxide Patent DE267906; hofmann chem ber, 1912 45, 3336; hofmann chem zentralbl, 1914 85 I, 199; hofmann 3-methoxy-4-hydroxy-propenylbenzene --> vanillin oxidation, yield 58%, rhodococcus rhodochrous MTCC 289, 3 days, 30C, pH6 indian j chem sect b, 1999 38 5, 538-541; t chatterjee, b k de, d k bhattacharyya 3-methoxy-4-hydroxy-propenylbenzene --> vanillin air, terpentine oil Patent DE150981; froger-delapierre 3-methoxy-4-hydroxy-propenylbenzene --> vanillin ozone, sodium disulfite Patent DE192565; spurge 3-methoxy-4-hydroxy-propenylbenzene --> vanillin alkali, electrolysis patent, Patent DE92007; chem fabr v heyden fortschr teerfarbenfabr verw industriezweige, 4, 1279; chem fabr v heyden 3-methoxy-4-hydroxy-propenylbenzene --> vanillin peroxidene, alkali Patent DE93938; haarmann & reimer fortschr teerfarbenfabr verw industriezweige, 4, 1277; haarmann & reimer 3-methoxy-4-hydroxy-propenylbenzene --> vanillin manganese saltene Patent DE189178; lang |
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3base (Newbee) 06-04-02 20:05 No 317565 |
isoeugenole --> vanillin (Rated as: excellent) |
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isoeugenole --> vanillin Reaction Details 1 of 22; 2 of 22 ; 3 of 22 ; 22 of 22 Reaction Classification Preparation Reagent H2O2 tert-butyl alcohol or tert-pentyl alcohol Other Conditions Reagens 4: CrO3 or V2O5 Note 1 Handbook Ref. 1 1363245; Patent; Research Corp.; Patent US2437648; 1943. Ref. 2 1587093; Patent; Research Corp.; Patent US2402566; 1942. Ref. 3 1587094; Patent; Research Corp.; Patent US2414385; 1942. Ref. 4 519401; Journal; Milas; JACSAT; J.Amer.Chem.Soc.; 59; 1937; 2342. Reaction Details 4 of 22 Reaction Classification Preparation Reagent aqueous H2O2 sulfanilic acid peroxidase-substance Note 1 Handbook Ref. 1 1987161; Journal; Manskaja; Emeljanowa; BIOHAO; Biokhimiya (Moscow); 7; 1942; 109,111; Chem.Abstr.; 1943; 4525. Reaction Details 5 of 22 Reaction Classification Preparation Reagent ozone Note 1 Handbook Ref. 1 1545909; Journal; Anonymus; JSCIAN; J.Soc.Chem.Ind.London; 41; 1922; 70 R. Ref. 2 507359; Journal; Briner; v. Tscharner; Paillard; HCACAV; Helv.Chim.Acta; 8; 1925; 407. Ref. 3 1545911; Journal; Briner; Patry; de Luserna; HCACAV; Helv.Chim.Acta; 7; 1924; 71. Reaction Details 6 of 22 Reaction Classification Preparation Reagent aqueous alkali Other Conditions elektrolytische Oxydation an Platin-Anoden Note 1 Handbook Ref. 1 1982322; Journal; Lowy; Moore; Trans.am.elektroch.Soc.; 42; 276,280; CHZEA6; Chem.Zentralbl.; GE; 94; III; 1923; 1516. Reaction Details 7 of 22 Reaction Classification Preparation Reagent aqueous alkali Temperature 0 - 12 C Other Conditions elektrolytische Oxydation an Bleidioxyd-Anoden Note 1 Handbook Ref. 1 1541589; Journal; Fichter; Christen; HCACAV; Helv.Chim.Acta; 8; 1925; 333. Reaction Details 8 of 22 Reaction Classification Preparation Reagent oxygen glacial acetic acid Note 1 Handbook Ref. 1 1533646; Journal; Harries; Haarmann; CHBEAM; Chem.Ber.; 48; 1915; 40. Reaction Details 9 of 22 Reaction Classification Preparation Reagent air acetic acid Temperature 50 - 60 C Other Conditions Irradiation.mit ultraviolettem Licht Note 1 Handbook Ref. 1 1533596; Genthe & Co.; Patent DE224071; FTFVA6; Fortschr.Teerfarbenfabr.Verw.Industriezw Reaction Details 10 of 22 Reaction Classification Preparation Reagent ozone glacial acetic acid Note 1 Handbook Ref. 1 500446; Journal; Otto; ANCPAC; Ann.Chim.(Paris); <7> 13; 1898; 123. Ref. 2 1533598; Journal; Witt; CHBEAM; Chem.Ber.; 48; 1915; 232. Ref. 3 1533646; Journal; Harries; Haarmann; CHBEAM; Chem.Ber.; 48; 1915; 40. Ref. 4 1523833; Otto; Verley; DE97620; FTFVA6; Fortschr.Teerfarbenfabr.Verw.Industriezw DE; GE; 4; 1280. Reaction Details 11 of 22 Reaction Classification Preparation Reagent ozone acetic acid ester Other Conditions man reduziert das entstandene Ozonid in Aether mit Zink und Eisessig Note 1 Handbook Ref. 1 1533646; Journal; Harries; Haarmann; CHBEAM; Chem.Ber.; 48; 1915; 40. Reaction Details 12 of 22 Reaction Classification Preparation Reagent air Other Conditions durch Ueberleiten des Dampfes ueber eine gluehende Platinspirale Note 1 Handbook Ref. 1 1296879; Journal; Trillat; COREAF; C.R.Hebd.Seances Acad.Sci.; 133; 1901; 822; BSCFAS; Bull.Soc.Chim.Fr.; <3>29; 1903; 41. Reaction Details 13 of 22 Reaction Classification Preparation Reagent alkali chlorate osmium tetroxide Note 1 Handbook Ref. 1 1977927; Hofmann; Patent DE267906. Ref. 2 1977928; Journal; Hofmann; CHBEAM; Chem.Ber.; 45; 1912; 3336; CHZEA6; Chem.Zentralbl.; GE; 85; I; 1914; 199. Reaction Details 14 of 22 Reaction Classification Preparation Reagent aqueous alkali Other Conditions elektrolytische Oxydation an Eisen-Anoden Note 1 Handbook Ref. 1 1982322; Journal; Lowy; Moore; Trans.am.elektroch.Soc.; 42; 276,280; CHZEA6; Chem.Zentralbl.; GE; 94; III; 1923; 1516. Reaction Details 15 of 22 Reaction Classification Preparation Yield 58 percent (BRN=472792) Reagent Rhodococcus rhodochrous MTCC 289 Time 3 day(s) Temperature 30 C pH-Value 6.0 Reaction Type Oxidation Ref. 1 6222516; Journal; Chatterjee, T.; De, B. K.; Bhattacharyya, D. K.; IJSBDB; Indian J.Chem.Sect.B; EN; 38; 5; 1999; 538 - 541. Reaction Details 16 of 22 Reaction Classification Preparation Reagent aqueous alkali Other Conditions elektrolytische Oxydation an Bleidioxyd-Anoden Note 1 Handbook Ref. 1 1982322; Journal; Lowy; Moore; Trans.am.elektroch.Soc.; 42; 276,280; CHZEA6; Chem.Zentralbl.; GE; 94; III; 1923; 1516. Reaction Details 17 of 22 Reaction Classification Preparation Reagent air terpentine oil Note 1 Handbook Ref. 1 1523719; Froger-Delapierre; Patent DE150981. Reaction Details 18 of 22 Reaction Classification Preparation Reagent ozone sodium disulfite Note 1 Handbook Ref. 1 1523721; Spurge; Patent DE192565. Reaction Details 19 of 22 Reaction Classification Preparation Reagent alkali Other Conditions Electrolysis Note 1 Handbook Ref. 1 1973055; Chem. Fabr. v. Heyden; Patent DE92007; FTFVA6; Fortschr.Teerfarbenfabr.Verw.Industriezw Reaction Details 20 of 22 Reaction Classification Preparation Reagent peroxidene alkali Note 1 Handbook Patent DE 93938 (http://l2.espacenet.com/espacenet/viewe haarmann & reimer Fortschr.Teerfarbenfabr.Verw.Industriezw Reaction Details 21 of 22 Reaction Classification Preparation Reagent manganese saltene Note 1 Handbook Ref. 1 1669893; Lang; Patent DE189178. isoeugenole --> vanillin nitrobenzene, aqueous KOH, 120-130°C Kimura; KGKZA7; Kogyo Kagaku Zasshi; 40; 1937; 600, 603; Kimura; J. Soc. chem. Ind. Japan Spl.; 40; 1937; 277. isoeugenole --> vanillin acetic acid, air oxygen, ultraviolettes Licht.Irradiation Patent DE224071; Genthe & Co. FTFVA6; Fortschr.Teerfarbenfabr.Verw.Industriezw isoeugenole --> vanillin air, an der gluehenden Platinspirale Trillat; COREAF; C.R.Hebd.Seances Acad.Sci.; 133; 1901; 822; Trillat; BSCFAS; Bull.Soc.Chim.Fr.; <3>29; 1903; 41. isoeugenole --> vanillin aqueous NaOH, 4-nitro-benzoic acid or 3-nitro-benzenesulfonic acid or 2-chloro-5-nitro-benzenesulfonic acid Hoffmann-La Roche; Patent DE578037; 1931; FTFVA6; Fortschr.Teerfarbenfabr.Verw.Industriezw isoeugenole --> vanillin aqueous OsO4-solution Hofmann; CHBEAM; Chem.Ber.; 45; 1912; 3336 Hofmann; CHZEA6; Chem.Zentralbl.; GE; 85; I; 1914; 199 isoeugenole --> vanillin oxygen, terpenes Patent DE150981; froger-delapierre isoeugenole --> vanillin hydrogen peroxide, V2O5 or CrO3, 2-methyl-propan-2-ol or 2-methyl-butan-2-ol Ref. 1 1587093; Research Corp.; Patent US2402566; 1942. Ref. 2 1587094; Research Corp.; Patent US2414385; 1942. Ref. 3 519401; Journal; Milas; JACSAT; J.Amer.Chem.Soc.; 59; 1937; 2342. eugenol --> vanillin chem trade j and chem engr 3 (1925) isoeugenole --> 1-(4-hydroxy-3-methoxy-phenyl)-propane-1 --> 2-hydroxy-1-(4-hydroxy-3-methoxy-phenyl) --> 1-Hydroxy-1-(4-hydroxy-3-methoxy-phenyl) --> vanillin 30% H2O2, HOAc, solvent aq ethanol, 5h, ambient temperature, further byproducts given phytochemistry, 1990 29 5, 1653-1659; (english) rupert kraus, gerhard spiteller |
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3base (Newbee) 06-04-02 20:32 No 317569 |
benzaldehydes from cinnamic acids (Rated as: excellent) |
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cinnamic acid --> benzaldehyde potassium dichromate, diluted H2SO4 justus liebigs ann chem, 1839 31, 271; simon cinnamic acid --> benzaldehyde water, 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 --> anisaldehyde KMnO4 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. ../rhodium /benzald sinapic acid --> syringaldehyde autoclaving 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. |
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3base (Newbee) 06-04-02 20:51 No 317572 |
benzaldehydes from styrenes | Bookmark | ||||||
oxidation with MnO2 and aq H2SO4 (1) methyl-isoeugenol --> veratric aldehyde; in the presence of sulphanilic acid (2) anethol --> anisaldehyde; in the presence of sulphanilic acid (3) styrene --> benzaldehyde (5) b-methyl styrene --> benzaldehyde (6) anethol --> anisaldehyde; with pyrolusite in the presence of sulphuric acid and of sulphanilic acid (7,8) methyl-isoeugenol --> veratric aldehyde; by a mixture of manganese dioxide and sodium dichromate in the presence of sulphuric acid and sulphanilic acid Patent GB774608, 1957-05-15, (equivalents: CH330121, DE1024500, FR1120496) "a process for the preparation of aromatic carbonyl compounds from aryl ethylenes" POLAK & SCHWARZ S ESSFNCEFABRI |
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3base (Newbee) 06-04-02 20:55 No 317574 |
benzoic acids from styrenes | Bookmark | ||||||
cleavage of of styrenes under photoirradiation synlett, 2002 3, 522-524 "oxidative cleavage of the double bonds of styrenes with a combination of mesoporous silica FSM-16 and I2 under photoirradiation" akichika itoh, tomohiro kodama, yukio masaki, shinji inagaki abstract: a mesoporous silica FSM-16 was found to be a recyclable promoter for the oxidative cleavage of double bonds, which are conjugated with an aromatic nucleus, to afford the corresponding carboxylic acid in the presence of catalytic iodine under photoirradiation conditions. styrene --> benzoic acid chemical communications, 1999 (1), 37-38 "heterogeneously catalysed cleavage of carbon-carbon double bonds with hydrogen peroxide using calcined heteropolyacids on oxide supports" christopher d. brooks , ling-chu huang , moya mccarron, robert a. w. johnstone abstract: reaction of an alkene with aqueous hydrogen peroxide and a catalytic quantity of a heteropolyacid adsorbed onto magnesium, aluminium or zinc oxide leads to complete, rapid cleavage of the alkene to give carbonyl compounds. |
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3base (Newbee) 06-04-02 21:01 No 317578 |
diol cleavage route | Bookmark | ||||||
isosafrole glycol --> piperonal Patent JP60070193, 1985-04-20 "production of piperonal" TORII SHIGERU; TAKASAGO KORYO KOGYO KK PURPOSE: To produce piperonal at a high yield by electrolyzing isosafrole glycol in an org. solvent or a solvent mixture composed of the org. solvent and water in the presence of a specific electrolyte. CONSTITUTION: The isosafrole glycol expressed by the formula ( I ), the hydroxide, halide and carbonate of an alkali metal, the halide of an alkaline earth metal and other electrolytes are put together with pentane, heptane, octane and other org. solvents into a reaction vessel and are made into an electrolyte. Water is added if necessary to the org. solvent in this case and the isosafrole glycol is incorporated at 0.01-50% concn. into the electrolyte. The electrolyte is so adjusted as to have 0.1-25% concn. An anode and cathode formed of Au, Pt, stainless steel, etc. are dipped in the electrolyte and after electrolysis is performed at 1-100A/cm2 current density, piperonal is produced at a high yield by solvent extraction, distillation, etc. of the conventional method. C=C bond cleavage of aromatic diols in hexane under relatively mild conditions journal of chemical research (synopses), 1998 (6), 308-309 "oxidation by chemical manganese dioxide. part 1. facile oxidation of benzylic alcohols in hexane" masao hirano, sigetake yakaba, hideki chikamori, james h. clark, takashi morimoto abstract: an inexpensive, stable, commercially available reagent, chemical manganese dioxide, can be used for the oxidation of a wide variety of benzylic alcohols and the C-C bond cleavage of aromatic diols in hexane under relatively mild conditions. |
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Rhodium (Chief Bee) 06-04-02 23:20 No 317616 |
Oxidation by Chemical Manganese Dioxide | Bookmark | ||||||
The latter article (MnO2 oxidation) is available free of charge here: http://www.rsc.org/CFmuscat/intermediate |
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3base (Hive Bee) 06-05-02 18:48 No 317874 |
benzaldehydes from styrenes | Bookmark | ||||||
Patent GB774608, 1957-05-15, (Patent DE1024500) this patent names some other nice refs for the preparation of benzaldehydes from styrenes like anisaldehyde from anethol via oxidation by ozonizaion, nitrobenzene, dichromate, ... |
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3base (Hive Bee) 06-05-02 19:11 No 317876 |
isosafrole --> piperonal (V2O5, yield 67.4%) (Rated as: excellent) |
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Piperonal from Isosafrole Five grams of isosafrole (Eastman Kodak Company) was mixed with 45 cc. of the peroxide reagent and to the mixture was added 0.02 g. of vanadium pentoxide. As the catalyst dissolved, the mixture heated up as before to almost the b. p. of the solvent. The reaction was over in about two hours when the mixture was still blood red due perhaps to the presence of the addition complex between vanadium pentoxide and piperonal.(12) The yield (67.4%) of piperonal, in this case, was also estimated by precipitating its P-nitrophenyl- hydrazone.(10) This P-nitrophenylhydrazone was recrystal- lized twice from 95% ethyl alcohol, mp 202-203'. An authentic sample prepared and purified in the same way had a mp of 203-203.5°; mixed mp showed no depression. In another experiment in which 0.02 g. of chromium trioxide was used as the catalyst, the yield of piperonal was only 14%. further procedures are given for: Isoeugenol --> Vanillin (yield 66%) Anethole --> Anisaldehyde (yield 55%) J. Am. Chem. Soc.; 1937; 59(11); 2342-2344. "The Hydroxylation of Unsaturated Substances. III. The Use of Vanadium Pentoxide and Chromium Trioxide as Catalysts of Hydroxylation"; Nicholas A. Milas |
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Rhodium (Chief Bee) 06-05-02 19:19 No 317877 |
What is "the peroxide reagent"? | Bookmark | ||||||
What is "the peroxide reagent"? |
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3base (Hive Bee) 06-05-02 19:43 No 317882 |
Re: What is "the peroxide reagent"? | Bookmark | ||||||
> What is "the peroxide reagent"? hi rhodium, the paper says: Vanadium Pentoxide This catalyst may be obtained from the Vanadium Corporation of America or it may be prepared in accordance with the method described elsewhere(5) Vanadium pentoxide is almost entirely insoluble in tertiary butyl or tertiary amyl alcohol but, when the latter contains hydrogen peroxide, it goes promptly into solution to form blood red pervanadic acid(6) The reaction mixture, as a rule, remains blood red until the end of the reaction when either the vanadium pentoxide precipitates out as a dark brown solid, or re- mains in solution as blue or green lower oxide. In every case the catalyst may be rejuvenated easily by the addition of more peroxide reagent. |
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Rhodium (Chief Bee) 06-05-02 21:28 No 317904 |
Ok, so it is H2O2 in conjunction with V2O5 - but ... | Bookmark | ||||||
Ok, so it is H2O2 in conjunction with V2O5 - but there is no information on the concentration of H2O2, just "45ml" per 5g isosafrole. |
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Bwiti (PVC-Analog Taste-Tester) 06-07-02 09:30 No 318500 |
Fuck ActiveX | Bookmark | ||||||
What's up Rhodium?! I went to that link you provided, and I can't view it because I don't have an object handler called "ActiveX". The download page for this software at microsoft is fucked, it doesn't even tell me where else I can find this software. When I go to that link and try to view the full article, it says “There is no viewer available for the type of object you are trying to open”. I’ve downloaded and ran about 8 different software programs. Don’t have a clue what I’m doing. Could someone please go to http://www.rsc.org/CFmuscat/intermediate Check-out example 3 from GB774608 1920 grams of water and 617 grams of manganese dioxide of 66.9 % purity (4.75 mols) are introduced into a reaction flask. The mixture is heated to 1000 C. and 208 grams (2.00 mols) of styrene are added. A gentle stream of nitrogen is introduced into the apparatus and in 55 minutes a mixture of 2236 grams of water and 1118 grams of sulphuric acid cooled to room temperature is added at 100 C. Stirring is continued for 1 hour 20'Sminutes at the same temperature. The reaction mixture is worked up and undistillable materials are discarded by a distillation in vacuum without the use of a column. In the distillate the components are identified by analytical methods. 28.8% of the styrene Introduced, 28.3% of the theoretical yield of benzaldehyde and 8.1% of the theoretical yield of benzoic acid are present The total yield of oxidation products is about 51% of the theoretical amount calculated on the converted starting material. By fractionation of the reaction product, benzaldehyde with the boiling point 90 C, at 42 torr, nD20 = 1.5440 and of 97.5 % purity is obtained. 1000 C? I hope they meant to say 100 C! Anyway, with yields that lousy, then why not replace the styrene with an equimolar amount of toluene? Love my country, fear my government. |
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Elementary (Hive Addict) 06-07-02 11:22 No 318528 |
Here you go | Bookmark | ||||||
You should be able to read it if you have acrobat reader installed. Anyway I've converted it to jpeg's for you mate. Here are the links http://geocities.com/c6h5uk3/1.jpg http://geocities.com/c6h5uk3/2.jpg John Lennon - Working Class Hero |
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Bwiti (PVC-Analog Taste-Tester) 06-08-02 03:35 No 318729 |
Cool | Bookmark | ||||||
I already have acrobat reader. Love/Hate relationship with my computer. Thanks for converting it to a jpg! Much appreciated! Love my country, fear my government. |
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3base (Hive Bee) 06-09-02 14:28 No 319101 |
piperonal from isosafrole via ozonolysis | Bookmark | ||||||
isosafrole --> piperonal ozonolysis, yield 87% advan chem ser, 1958 21: 149; c a sublunskey et al Patent US2776986; C.A., 1957 51: 8141 |
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pROcon (Hive Bee) 06-12-02 01:11 No 319957 |
Could one of you take a moment to explain to me ... | Bookmark | ||||||
Could one of you take a moment to explain to me why you pluralise the word benzaldehydes? benzaldehyde is unambiguously C6H5CHO, synthetic bitter almond oil, no? Or are aldehydes always pluralised when there s more than a single molecule? don't call me...I wont answer, or call you back. |
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Rhodium (Chief Bee) 06-12-02 03:19 No 319995 |
He is referring to that several different ... | Bookmark | ||||||
He is referring to that several different benzaldehydes can be made from several different styrenes, and that the reaction is not limited to a special variety of benzaldehyde. |
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