Alkynes презентация

ALKYNES GROUP MEMBERS: 1)Toktassyn Olzhas 2)zHARKYNulY YEDIL 3)Sattarov satzhan 4)Alpyssov madi

BOND Hydrocarbons that contain the carbon-carbon triple bond –C (triple)C- are called alkynes. Each triple bond contains one sigma (σ) and two pi (π) bonds. Because of the π bonds in their structure alkynes are unsaturated hydrocarbons.

GENERAL FORMULA The general formula of alkynes is CnH2n–2 where n is an integer starting from 2. Alkynes are named by using the –yne suffix in place of the –ane suffix of alkanes.

ALKYNYL GROUP Alkynyl groups are formed from alkynes by removing one H atom. The most common alkynyl groups are ethynyl, 1–propynyl, and 1–butynyl

NOMENCLATURE The naming of alkynes is similar to that of other hydrocarbons. Alkynes may contain more than one triple bond. An alkyne with two triple bonds is called an alkadiyne. Alkenynes

CYCLOALKYNES Alkynes may be cyclo compounds (cycloalkynes). The simplest stable cycloalkyne at room temperature is cyclononyne.

ISOMERISM The triple bond may be in different locations in an alkyne, so alkynes can exhibit structural isomerism.

PHYSICAL PROPERTIES Similar to alkanes, alkenes. 1)Insoluble in water. BUT 2)Soluble in organic solvents 3)Density less than water

CHEMICAL PROPERTIES Alkynes are unsaturated compounds and their chemical properties are similar to alkenes. Alkynes undergo combustion reactions and addition reactions, as alkenes do. In addition, alkynes undergo substitution reactions with metals.

COMBUSTION REACTIONS

ADDITION REACTIONS Addition reactions occur by breaking the π bonds of the triple bond. Hydrogen, halogens, hydrogen halides and water may give addition reactions with alkynes.

ADDITION OF HYDROGEN Two hydrogen molecules are added to one triple bond using a nickel, platinum or palladium catalyst. Alkenes are the intermediate products.

PREPERATION OF ALKYNES Alkynes can be synthesized from metallic acetlylides and alkyl halides.

ACETYLENE Acetylene, the first member of the alkyne series, is one of the major chemicals used in industry.

USES OF ALKYNES Histrionicotoxin toxic alkyne present in South American frogs used to make poison-tipped arrows   Ichthyothereol highly toxic alkyne found in the leaves of a Brazilian herb used to kill fish Calicheamicin and Esperamicin extremely toxic to cells breaks double strand of DNA researchers are trying to use it to develop a cancer fighting drug   Capillin natural plant fungicide

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