Aldehydes and Ketones - Structure and Nomenclature PDF

Aldehydes and Ketones Structure and Nomenclature Prepared by: Nickielyn B. Lauriano Trixie S. Nadayao Marc Jayson Rendan  Learning Objectives  Identify the general structure for an aldehyde and a ketone.  Use common names to name aldehy...

Aldehydes and Ketones Structure and Nomenclature Prepared by: Nickielyn B. Lauriano Trixie S. Nadayao Marc Jayson Rendan  Learning Objectives  Identify the general structure for an aldehyde and a ketone.  Use common names to name aldehydes and ketones.  Use the IUPAC system to name aldehydes and ketones. INTRODUCTION Aldehydes and ketones contain the carbonyl group. Aldehydes are considered the most important functional group. They are often called the formyl or methanoyl group. Aldehydes derive their name from the dehydration of alcohols. Aldehydes contain the carbonyl group bonded to at least one hydrogen atom. Ketones contain the carbonyl group bonded to two carbon atoms. Aldehydes and Ketones are organic compounds which incorporate a carbonyl functional group, C=O. The carbon atom of this group has two remaining bonds that may be occupied by hydrogen, alkyl or aryl substituents. If at least one of these substituents is hydrogen, the compound is an aldehyde. If neither is hydrogen, the compound is a ketone. STRUCTURE OF ALDEHYDES  Aldehydes contain the carbonyl group bonded to at least one hydrogen atom. NAMING ALDEHYDES  The IUPAC system of nomenclature assigns a characteristic suffix -al to aldehydes.  For example, H2C=O is methanal, more commonly called formaldehyde.  Since an aldehyde carbonyl group must always lie at the end of a carbon chain, it is always is given the #1 location position in numbering and it is not necessary to include it in the name. There are several simple carbonyl containing compounds which have common names which are retained by ALDEHYDES NOMENCLATURE 1. RULES Aldehydes take their name from their parent alkane chains. The -e is removed from the end and is replaced with -al. 2. The aldehyde funtional group is given the #1 numbering location and this number is not included in the name. 3. For the common name of aldehydes start with the common parent chain name and add the suffix -aldehyde. Substituent positions are shown with Greek letters. 4.When the -CHO functional group is attached to a ring the suffix -carbaldehyde is added, and the carbon attached to that group is C1.  EXAMPLES The IUPAC system names are given on top while the common name is given on the bottom in parentheses. Aldehydes Common Names to Memorize KETONE S  In a Ketone, two carbon groups are attached to the carbonyl carbon atom. The following general formulas, in which R represents an alkyl group and Ar stands for an aryl group, represent ketones. STRUCTU RE AMING KETONES The IUPAC system of nomenclature assigns a characteristic suffix of -one to ketone. A ketone carbonyl function may be located anywhere within a chain or ring, and its position is usually given by a location number. Chain numbering normally starts from the end nearest the carbonyl group.  Very simple ketones, such as propanone and phenylethanone do not require a locator number, since there is only one possible site for a ketone carbonyl function. The common names for ketones are formed by naming both alkyl groups attached to the carbonyl then adding the suffix -ketone. The attached alkyl groups are arranged in the name alphabetically.  KETONE NOMENCLATURE RULES 1.Ketones take their name from their parent alkane chains. The ending -e is removed and replaced with -one. 2.The common name for ketones are simply the substituent groups listed alphabetically + ketone. 3.Some common ketones are known by their generic names. Such as the fact that propanone is commonly referred to as acetone.  EXAMPLES The IUPAC system names are given on top while the common name is given on the bottom in parentheses. Ketones Common Names to Memorize Naming Aldehydes and Ketones in the Same Molecule  As with many molecules with two or more functional groups, one is given priority while the other is named as a substituent.  Because aldehydes have a higher priority than ketones, molecules which contain both functional groups are named as aldehydes and the ketone is named as an "oxo" substituent.  It is not necessary to give the aldehyde functional group a location number, however, it is usually necessary to give a location number to the ketone. EXAMPLES Naming Dialdehydes and Diketones  For dialdehydes the location numbers for both carbonyls are omitted because the aldehyde functional groups are expected to occupy the ends of the parent chain.  The ending –dial is added to the end of the parent chain name.  Naming Dialdehydes and Diketones For diketones both carbonyls require a location number. The ending- dione or -dial is added to the end of the parent chain. EXAMPL ES SIGNIFICANCE OF ALDEHYDE AND KETONE IN DAILY LIFE Org Chem (lec  Aldehydes and ketones are organic compounds that play significant roles in various aspects of daily life. Here are some examples:  Aldehydes 1. Food industry: Vanillin (an aldehyde) is used as a flavoring agent in foods, beverages, and pharmaceuticals 2. Perfumes and fragrances: Aldehydes like benzaldehyde and cinnamaldehyde are used in perfumes, soaps, and cosmetics. 3. Pharmaceuticals: Aldehydes are used as intermediates in the synthesis of certain drugs, such as sedatives and antihistamines. 4. Plastics and adhesives: Formaldehyde (an aldehyde) is used in the production of plastics, adhesives, and resins. 5. Preservation: Formaldehyde is used as a disinfectant and preservative in medical and industrial applications.  Ketone 1. Solvents: Acetone (a ketone) is a common solvent in nail polish removers, paint thinners, and cleaning agents. 2. Pharmaceuticals: Ketones like acetone and methyl ethyl ketone are used as solvents and intermediates in drug synthesis. 3. Cosmetics: Ketones like acetone and diacetone alcohol are used in skincare products, hair care products, and perfumes. 4. Food industry: Diacetyl (a ketone) is used as a flavoring agent in butter, margarine, and other food products. 5. Biotechnology: Ketones are used as energy sources in biotechnological applications, such as biofuel production. THANK YOU