Methods of Preparation of Alkenes in the Laboratory | Mechanism

Methods of Preparation of Alkenes

Alkenes belong to the family of hydrocarbons. They contain at least one double bond between two adjacent carbon atoms. The general chemical formula of an alkene is CnH2n. Alkenes can be prepared via various methods. A few methods of preparation of alkenes have been detailed in this article.

From alkynes: Alkynes can be used for the preparation of alkenes. Alkyne to alkene conversion is carried out by the reduction of alkynes with hydrogen in the presence of palladised charcoal. The charcoal used is moderately deactivated with the help of quinoline or sulphur compounds. This reaction results in the formation of alkenes. Palladised charcoal which is halfway deactivated is called as Lindlar’s catalyst. The alkenes obtained from the above reaction have cis geometry. In order to form trans alkenes, alkynes are made to undergo reduction with sodium in liquid ammonia.

Alkenes belong to the family of hydrocarbons. They contain at least one double bond between two adjacent carbon atoms. The general chemical formula of an alkene is CnH2n. Alkenes can be prepared via various methods. A few methods of preparation of alkenes have been detailed in this article.

From alkyl halides: Alkenes are obtained by heating alkyl halides with alcoholic potash. Alcoholic potash is obtained by dissolving potassium hydroxide in alcohol. In this reaction, dehydrohalogenation takes place i.e. a single molecule of halogen acid is removed. The rate of reaction depends upon the alkyl group and the nature of the halogen group attached.

Alkenes belong to the family of hydrocarbons. They contain at least one double bond between two adjacent carbon atoms. The general chemical formula of an alkene is CnH2n. Alkenes can be prepared via various methods. A few methods of preparation of alkenes have been detailed in this article.

From vicinal halides: Vicinal dihalides can be defined as the dihalides in which two adjacent carbon atoms are attached to two halogens. When such dihalides react with zinc metal, they lose halogen molecules which result in the formation of alkenes. Such a reaction of preparation of alkenes from Vicinal dihalides is known as dehalogenation.

Alkenes belong to the family of hydrocarbons. They contain at least one double bond between two adjacent carbon atoms. The general chemical formula of an alkene is CnH2n. Alkenes can be prepared via various methods. A few methods of preparation of alkenes have been detailed in this article.

From alcohols: Alcohols react with concentrated sulphuric acid which results in the formation of alkenes due to the elimination of a water molecule. As water molecule is removed in this reaction, it is called as acidic dehydration of alcohol and the dehydrating agent is concentrated sulphuric acid.

Alkenes belong to the family of hydrocarbons. They contain at least one double bond between two adjacent carbon atoms. The general chemical formula of an alkene is CnH2n. Alkenes can be prepared via various methods. A few methods of preparation of alkenes have been detailed in this article.

Er. Neeraj K.Anand is a freelance mentor and writer who specializes in Engineering & Science subjects. Neeraj Anand received a B.Tech degree in Electronics and Communication Engineering from N.I.T Warangal & M.Tech Post Graduation from IETE, New Delhi. He has over 30 years of teaching experience and serves as the Head of Department of ANAND CLASSES. He concentrated all his energy and experiences in academics and subsequently grew up as one of the best mentors in the country for students aspiring for success in competitive examinations. In parallel, he started a Technical Publication "ANAND TECHNICAL PUBLISHERS" in 2002 and Educational Newspaper "NATIONAL EDUCATION NEWS" in 2014 at Jalandhar. Now he is a Director of leading publication "ANAND TECHNICAL PUBLISHERS", "ANAND CLASSES" and "NATIONAL EDUCATION NEWS". He has published more than hundred books in the field of Physics, Mathematics, Computers and Information Technology. Besides this he has written many books to help students prepare for IIT-JEE and AIPMT entrance exams. He is an executive member of the IEEE (Institute of Electrical & Electronics Engineers. USA) and honorary member of many Indian scientific societies such as Institution of Electronics & Telecommunication Engineers, Aeronautical Society of India, Bioinformatics Institute of India, Institution of Engineers. He has got award from American Biographical Institute Board of International Research in the year 2005.