v. Braun, Julius published the artcileThe reaction of aldehydes with metals and their catalytic pressure hydrogenation, Category: catalysis-chemistry, the publication is Berichte der Deutschen Chemischen Gesellschaft [Abteilung] B: Abhandlungen (1934), 1696-712, database is CAplus.
On hydrogenation under pressure at high temperatures with Ni, nonaromatic aldehydes give, along with the expected primary alcs., considerable quantities of unsaturated OH compounds with double the number of C atoms, e. g., C14H29OH from enanthal, C7H14O (C. A. 18, 814). On the assumption that they are straight-chain compounds (Me(CH2)6CH(OH)(CH2)5Me from enanthal), it seemed that they might be formed according to 1 of the 2 following schemes (it was shown that they are not produced through a glycol RCH(OH)CH(OH)R formed primarily): RCH2CHO + OHCCH2R ¡ú RCH2CH(OH)COCH2R (I) ¡ú RCH:CHCOCH2R (II) ¡ú RCH2CH2CH(OH)CH2R (III), or RCH2CHO + OHCCH2R ¡ú RCH:CHOH + OHCCH2R ¡ú II ¡ú III. The first of these 2 possibilities, which seemed the more probable, is excluded by the fact that campholic and fencholic aldehydes, in which the CHO group is on a tertiary C atom, react exclusively like aromatic aldehydes with formation of the corresponding primary alcs. The 2nd possibility was also excluded by experiments made with special care on decylic aldehyde (IV). With Ni and H, IV gives, besides decyl alc., an alc. C20H41OH (V) which cannot be converted into crystalline eicosane; V or its bromide gives only an isomeric liquid eicosane (VI) and therefore the chain in V must be branched. The nature of the branching was shown by degradation experiments; the hydrogenation product of PrCHO gave pure BuCOEt, that of iso-BuCHO yielded iso-AmCOCHMe2, and that of enanthal formed C7H15COAm. The primary stage in the reduction of the aldehydes RCH2CHO must therefore be not RCH:CHOH but the aldol RCH2CH(OH)CHRCHO or the unsaturated aldehyde RCH2CH:CRCHO (VII). These aliphatic aldehydes RCH2CHO heated under N in steel autoclaves change rapidly, first into VI, and then into much higher boiling isomers with triple the mol. weight which, however, are not paraldehydes but the glycol esters, RCH2(OH)CHRCH2OCOCH2R (cf. Neust?dter, Monatsh. 27, 903(1906), and earlier papers by pupils of Lieben). The structure of these glycol esters has been confirmed by oxidation to the keto esters RCH2COCHRCH2OCOCH2R, and by dehydration to the unsaturated esters RCH2CH:CRCH2OCOCH2R which, after saponification, yield the unsaturated primary alcs. RCH2CH:CRCH2OH and then the saturated primary alcs. The change undergone by aldehydes heated in steel autoclaves is not a reaction of the aldehydes alone; the material of the autoclave plays a role. A considerable amount of metal powder (chiefly Cu, from the gaskets) was always formed; moreover, even at room temperature in the absence of air and moisture, aldehydes react distinctly with finely divided metals (Cu, Fe, Co, Ni, Cr, Zn, Mn) with primary evolution of H. In a short time colored solutions are formed, a flocculent metallic hydroxide gradually precipitates out, then a separation of water is observed, and after long standing VII and the glycol ester can be isolated as in the autoclave experiments, although the yields of glycol ester are much smaller. Presumably a metal enolate RCH:CHOM is first formed which yields with comparative ease the aldol RCH2CH(OM)CHRCHO and the latter changes, much less readily, through RCH2CH((CHRCHO)OCH((OM)CH2R and and through RCH2CH(CHRCHO)OCH(OM)CH2R and to RCH2CH(OM)CHRCH2OCOCH2R. In the cold, the aldol has time to change chiefly into the unsaturated aldehyde and metal hydroxide, whereas on heating the change into glycol predominates. Different metals vary distinctly in their influence on the reaction, but no relation between their influence and their properties (e. g., their position in the tension series) has as yet been established. All the experiments with metals at room temperature were made in Jena glass, so the alkalinity of the glass played no part. ¦Â-Decyl-¦Â-octylethyl alc. (V) b17 230¡ã; bromide, b0.4 195¡ã, reacts quite readily with Mg in ether, yielding asym-decyloctylethane (VI), b14 200¡ã, also obtained by catalytic hydrogenation with Pd and H of the ethylene, b12 193-5¡ã, d422.5 0.8102, which is best prepared by boiling the bromide with 2-3 mols. aqueous alc. KOH until free from halogen, precipitating with water and boiling 10-12 hrs. with 60% H2SO4. ¦Â-Butyl-¦Â-ethylethyl alc., from PrCHO, b15 84-6¡ã, d420 0.8381, nD 1.4335; bromide, b15 73-6¡ã, forms with NMe3 in benzene at 100¡ã the quaternary bromide BuEt-CHCH2NMe3Br, which m. above 200¡ã and yields on treatment with Ag2O and distillation with alkali the tertiary dimethylamine, b. 177-9¡ã (methiodide, m. 215¡ã), and asymbutylethylethylene, b. 116-18¡ã. The latter on ozonization gives BuCOEt. Heated 3 hrs. under N at 300¡ã in a steel autoclave, PrCHO gives 25% unchanged PrCHO, 50% ¦Áethyl-¦Â-propylacrolein, b. 172¡ã, and 15% of the glycol ester, C12H24O3, b10 148-50¡ã, saponified to PrCO2H and the glycol, C8H18O2, b12 131-3¡ã, d422 0.9789, nD12 1.4537. With 1 mol. PrCOCl in pyridine, the glycol regenerates the above ester and with 2 mols. chloride forms the dibutyrate, b12 154-8¡ã. The dichloride and dibromide, b0.2 50¡ã and 82¡ã, resp., from the glycol with concentrated HCl and HBr at 120¡ã, are unstable and lose considerable halogen acid when distilled in the vacuum of a water pump. The structure of the acrolein was established by hydrogenation with Pd and H and conversion of the oxime, C8H17ON, b10 104-6¡ã, of the product with PCl5 into the nitrile, b10 75¡ã, of BuEtCHCO2H. The glycol treated in a current of H with Beckmann’s mixture (2 atoms O) gives about 50% of a compound C8H14O2, b12 100-3¡ã (presumably chiefly the HO aldehyde PrCH(OH)CHEtCHO; oxime, b. 140-5¡ã), and the yellow diketone PrCOCOEt, b. 147-9¡ã. The latter is also formed, in very small amount, with the keto ester, PrCOCHEtCH2OCOPr, b. 130-4¡ã, from the glycol ester with CrO3AcOEt. The glycol ester is best dehydrated with PCl3 in CH2Cl2; the resulting ¦Á-ethyl-¦Â-propylallyl alc. (65-70% yield), b12 68-71¡ã, d422 0.8414, nD 1.4418; acetate, b. 79-81¡ã; bromide, b12 68-70¡ã, splits off HBr with cold water, forms with NMe3 a quaternary bromide, m. 175¡ã, and yields with NH4SCN the mustard oil, C8H15NCS, b. 105-10¡ã. The yield of glycol ester is not increased by adding the unsaturated aldehyde to the PrCHO before heating in the autoclave; the acrolein is therefore not an intermediate stage in the production of the glycol ester. That the acrolein is formed by direct dehydration of 2 mols. PrCHO is confirmed by the behavior of the PrCHO in the presence of BzH; heating after addition of BzH gives ¦Á-ethylcinnamaldehyde, b10 126-8¡ã, d422 1.0201, nD16 1.5847, which is reduced by Pd and H to ¦Â-ethyl-¦Â-benzylethyl alc., b10 126-8¡ã. ¦Â-Heptyl-¦Â-amylethyl alc., from enanthal, forms a bromide, b11, 154-6¡ã; the quaternary bromide obtained with NMe3 and the quaternary chloride are soluble in ether, and evaporation of the C6H6-Et2O solutions leaves viscous residues, but the chloroplatinate, C34H76N2Cl8Pt, seps. in golden yellow leaflets decomposing 218¡ã. The tertiary amine, Am(C7H15)CHCH2NMe2, b11 143-5¡ã, and the ethylene, Am(C7H15)C:CH2, b11 117-18¡ã, d422.5 0.7728, nD 1.4374; the latter on ozonization gives heptyl Am ketone, b11 128-9¡ã, m. 18.5¡ã, d425 0.8244, nD 1.4320. The glycol ester, C21H42O3, from enanthal, b0.3 176-8¡ã, d417 0.9012, nD 1.4554, is saponified by alkali to enanthic acid and the glycol, C6H13CH(OH)CHAmCH2OH, which distils under 12 mm. as a thick liquid; the diketone, b12 110¡ã, has not yet been obtained in entirely pure form. 2-Isopropyl-5-methylhexanol, from iso-BuCHO, b11 92-5¡ã; bromide, b11 92-5¡ã; trimethylammonium bromide, m. 152¡ã; dimethylamine, b. 196-8¡ã (methiodide, m. 132¡ã); asym-isoamylisopropylethylene, b. 150¡ã, d424 0.7387, nD24 1.4202; iso-Am iso-Pr ketone, b10 58¡ã, d425 0.8135, nD 1.4147; glycol ester, iso-BuCH(OH)CH(CHMe2)CH2OCOCH2CHMe2, b12 150-8¡ã (Rosiner, Monatsh. 22, 545(1901)), dehydrated by PCl3 and saponified with alkali, gives enanthic acid and ¦Á-isopropyl-¦Â-isobutylallyl alc., b12 80-5¡ã, d420 0.8375, nD 1.4485.
Berichte der Deutschen Chemischen Gesellschaft [Abteilung] B: Abhandlungen published new progress about 28056-87-3. 28056-87-3 belongs to catalysis-chemistry, auxiliary class Amine,Aliphatic hydrocarbon chain, name is 2-Ethyl-N,N-dimethylhexan-1-amine, and the molecular formula is C7H13NO2, Category: catalysis-chemistry.
Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia