摘要:

AbstractPhase‐transfer catalysis (PTC) has grown into a versatile preparative method in the last few years. The most notable new developments include the use of crown ethers as phase‐transfer catalysts and the introduction of solid‐liquid PTC. Some representative examples have been selected from the large number of new PTC reactions and some of them are summarized in t

ISSN:0570-0833    

DOI:10.1002/anie.197704933

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractAnalysis of the growth of the world's population shows that if no trenchant measures are taken, the number of the earth's inhabitants is likely to double to 8 billion people within as few as 35 years. Hormonal contraception is presently the best method available which would be capable of counteracting this trend. 6.5 tons of estrogen and 32 tons of progestogen would in theory be sufficient to protect the 500 million women of child‐bearing age from unwanted pregnancies for one year.—In addition, the history, industrial methods of synthesis, mode of action and side effects of steroid contraceptives as well as the possible future developments are briefly mentio

ISSN:0570-0833    

DOI:10.1002/anie.197705061

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractIn 1974 ProfessorsRowlandandMolinaof the University of California at Irvine developed a theory concerning the possible adverse impact of chlorofluorocarbons on the earth's ozone shield. These compounds are the working fluids responsible for the safety and efficiency of almost all air‐conditioning and refrigeration equipment and are used as propellants in many types of aerosol products.—The present article is divided into five sections. The first is an historical perspective of the scientific situation up to the end of 1974. The second section examines the various findings and observations on which the theory is founded and outlines new knowledge gained in this sector since early 1975. The third section is devoted to the possible consequences of ozone depletion while the fourth and fifth sections consider the question of the risk taken in delaying a decision to stop production of certain halocarb

ISSN:0570-0833    

DOI:10.1002/anie.197705131

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe electrical conductivity of a wide variety of organic materials is reviewed and a comparison made between those materials which transport charge efficiently and those that do not. This comparison reveals that the most efficient conductors contain molecules (a) whose radical ions form a new aromatic sextet upon one‐electron oxidation or reduction and (b) whose aromaticity can migrate by mixed‐valence interaction. The electrical data are presented in light of the chemistry of these materials and the importance of chemical bonding interactions in the electron transport process. Several new examples are discussed and directions for further research explo

ISSN:0570-0833    

DOI:10.1002/anie.197705191

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197705341

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197705351

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197705361

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197705381

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197705391

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197705401

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY