摘要:

AbstractThe secret of old Chinese porcelain is the technique by which a material, capable of forming extremely thin‐walled articles, was obtained from a slightly plastic kaolin. Intercalation compounds, which form by treating kaolinite with decaying urine, give the key to the preparation of this materia

ISSN:0570-0833    

DOI:10.1002/anie.196306971

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractAt low temperatures, ethylene and α‐olefins (Δ1‐olefins or 1‐alkenes) are rapidly converted into oligomrs by the two‐component organometallic catalyst CH3TiCl3·CH3AlCl2. To achieve smooth oligomerizations, aromatic or chlorinated hydrocarbons must be used as solvents. Although the activity of the titanium‐carbon bond is enhanced by the aluminum component of the catalyst, the aluminum and its methyl group do not participate in the reaction proper; the latter proceeds exclusively at the titanium‐carbon bond. The reaction will olefins can be used as an analytical method for the quantitative determination of the titanium‐carbon bond in admixture with the organoaluminum component. It is thus possible to follow the reaction leading to formation of the catalyst from titanium tertrachloride, as well as the processes occurring at the titanium‐carbon bond during the oligomerization of olefins. All the observations indicate that the catalyst possesses an ionic structure which is determined by the solvent. It is shown that the initial reaction step probably involves formation of a complex between the olefin and the alkyltitanium cation. The reaction scheme proposed is based on organometallic reactions which are characterized by carbanion and hydride transfers within the olefin‐cation complex. This mechanism, which is unusual for Ziegler catalysts, is due to the predominance

ISSN:0570-0833    

DOI:10.1002/anie.196307041

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractThe ring system of non‐anellated 1,2‐thiazoles (isothiazoles) has only recently become accessible. Four syntheses and numerous interconversions have opened up new routes to compounds which command interest as intermediates and as analogues of natural products and established pharmaceutic

ISSN:0570-0833    

DOI:10.1002/anie.196307141

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractWhen straight‐chain mono‐olefins, from pentene to decene, are subjected to the Koch carboxylic acid synthesis by the addition of CO and H2O or CH3OH in the presence of strongly acidic catalysts, not only the expected secondary acids, but also mixtures of a specific type of tertiary acids or their methyl esters are formed. When the catalysts contain boron trifluoride, the secondary acids are formed in ratios of isomers which are, within the scope of this investigation, independent of the experimental conditions and which agree well with the values calculated from the isomer equilibria of the corresponding n‐olefins. Using concentrated sulfuric acid as catalyst, a larger proportion of tertiary acids is obtained than with BF3‐catalysis, and amongst the secondary acids, those isomers predominate in which the COOH group is situated near the centre of the m

ISSN:0570-0833    

DOI:10.1002/anie.196307191

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractThe use of well‐known phenol oxidation reactions for the preparation of compounds arising from CC and CO coupling has recently received increased attention. A selection from the large number of products obtainable by oxidation of mono‐ and polyhydric phenols and a discussion of the reaction mechanisms indicate the scope of this method. The formation of hydroxyphenylquinones and orceine dyes from resorcinol derivatives is explained. The synthesis of natural products by way of phenol oxidations is briefly di

ISSN:0570-0833    

DOI:10.1002/anie.196307231

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196307363

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196307372

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196307383

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196307392

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196307402

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY