– In this topic, we will discuss the Fragmentation Patterns in Mass Spectrometry. Fragmentation Patterns in Mass Spectrometry – In addition to the molecular formula, the mass spectrum provides structural information. – An electron with a typical energy of 70 eV (6740 kJ mol or 1610 kcal mol) has far …
Read More »Determination of the Molecular Formula by Mass Spectrometry
Determination of the Molecular Formula by Mass Spectrometry – we can Determine the Molecular Formula by Mass Spectrometry and we will discuss : (A) High-Resolution Mass Spectrometry (B) Use of Heavier Isotope Peaks (A) High-Resolution Mass Spectrometry – Although mass spectra usually show the particle masses rounded to the nearest …
Read More »Mass Spectrometry : Introduction
Mass spectrometry (MS) provides the molecular weight and valuable information about the molecular formula, using a very small sample. Introduction to Mass Spectrometry – Infrared spectroscopy gives information about the functional groups in a molecule, but it tells little about the size of the molecule or what heteroatoms are present. …
Read More »Characteristic Absorptions of Carbonyl Compounds
– In this subject, we will talk about Characteristic Absorptions of Carbonyl Compounds such as Ketones, Aldehydes, Amines, and Acids. Characteristic Absorptions of Carbonyl Compounds – Because it has a large dipole moment, the C=O double bond produces intense infrared stretching absorptions. – Carbonyl groups absorb at frequencies around 1700 …
Read More »Characteristic Absorptions of Alcohols and Amines
– In this topic, we will discuss the Characteristic Absorptions of Alcohols and Amines by examples. Characteristic Absorptions of Alcohols and Amines – The O-H bonds of alcohols and the N-H bonds of amines are strong and stiff. – The vibration frequencies of O-H and N-H bonds therefore occur at …
Read More »Hydrocarbons: Infrared Spectroscopy of Hydrocarbons
Infrared Spectroscopy of Hydrocarbons – Hydrocarbons contain only carbon–carbon bonds and carbon–hydrogen bonds. – An infrared spectrum does not provide enough information to identify a structure conclusively (unless an authentic spectrum is available to compare “fingerprints”), but the absorptions of the carbon-carbon and carbon-hydrogen bonds can indicate the presence of …
Read More »IR Spectrum – Measurement of the IR Spectrum
– In this subject, we talk about how to Measure the IR Spectrum. Measurement of the IR Spectrum – Infrared spectra can be measured using liquid, solid, or gaseous samples that are placed in the beam of infrared light. – A drop of a liquid can be placed as a …
Read More »Inorganic Esters – Esters of Inorganic Acids
Esters of Inorganic Acids – In addition to forming esters with carboxylic acids, alcohols form inorganic esters with inorganic acids such as nitric acid, sulfuric acid, and phosphoric acid. – In each type of ester, the alkoxy (-OR) group of the alcohol replaces a hydroxyl group of the acid, with …
Read More »Esterification of Alcohols
– In this subject we will talk about the Esterification of Alcohols. What are Alcohols? – Alcohols are organic compounds containing hydroxyl (-OH) groups. – They are some of the most common and useful compounds in nature, in industry, and around the house. – The word alcohol is one of …
Read More »Reactions of Diols
Unique Reactions of Diols – Unique Reactions of Diols are: (1) The Pinacol Rearrangement (2) Periodic Acid Cleavage of Glycols (1) The Pinacol Rearrangement – Using our knowledge of alcohol reactions, we can explain results that seem strange at first glance. – The following dehydration is an example of the …
Read More »Reactions of Alcohols with Thionyl Chloride
Reactions of Alcohols with Thionyl Chloride – Reactions of Alcohols with Thionyl Chloride give alkyl chloride. – Thionyl chloride (SOCl2) is often the best reagent for converting an alcohol to an alkyl chloride. – The by-products (gaseous SO2 and HCl) leave the reaction mixture and ensure there can be no …
Read More »Reaction of Alcohols with Phosphorus Halides
Reaction of Alcohols with Phosphorus Halides – Reaction of Alcohols with Phosphorus Halides gives alkyl halides. – Several phosphorus halides are useful for converting alcohols to alkyl halides. – Phosphorus tribromide, phosphorus trichloride, and phosphorus pentachloride work well and are commercially available. 3 R-OH + PCl3 → 3 R-Cl + …
Read More »Reactions of Alcohols with Hydrohalic Acids
– In this topic the Reactions of Alcohols with Hydrohalic Acids such as HBr , HCl are discussed Reactions of Alcohols with Hydrohalic Acids – Tosylation of an alcohol, followed by displacement of the tosylate by a halide ion, converts an alcohol to an alkyl halide. – This is not …
Read More »Alcohols as Nucleophiles and Electrophiles
Alcohols as Nucleophiles and Electrophiles; Formation of Tosylates – One reason alcohols are such versatile chemical intermediates is that they react as both nucleophiles and electrophiles. – The following scheme shows an alcohol reacting as a weak nucleophile, bonding to a strong electrophile (in this case, a carbocation). – An …
Read More »Biological Oxidation of Alcohols
– In this topic, the Biological Oxidation of Alcohols and their effect on the humans and animals will be discussed Biological Oxidation of Alcohols – Although it is the least toxic alcohol, ethanol is still a poisonous substance. – When someone is suffering from a mild case of ethanol poisoning, …
Read More »Additional Methods for Oxidizing Alcohols
Additional Methods for Oxidizing Alcohols – Many other reagents and procedures have been developed for oxidizing alcohols. – Some are simply modifications of the procedures we have seen. – For example, the Collins reagent is a complex of chromium trioxide and pyridine, the original version of PCC. – The Jones …
Read More »Oxidation of Alcohols
Oxidation of Alcohols – Primary and secondary alcohols are easily oxidized (Oxidation of Alcohols) by a variety of reagents, including chromium oxides, permanganate, nitric acid, and even household bleach (NaOCl, sodium hypochlorite). – The choice of reagent depends on the amount and value of the alcohol. – We use cheap …
Read More »Oxidation states of Alcohols and Related Functional Groups
Oxidation states of Alcohols and Related Functional Groups – Oxidation states of Alcohols leads to ketones, aldehydes, and carboxylic acids. – These functional groups, in turn, undergo a wide variety of additional reactions. – For these reasons, alcohol oxidations are some of the most common organic reactions. – In inorganic …
Read More »Thiols (Mercaptans)
What is Thiols? – Thiols are sulfur analogues of alcohols, with an -SH group in place of the alcohol -OH group. – Oxygen and sulfur are in the same column of the periodic table (group 6A), with oxygen in the second row and sulfur in the third. Nomenclature of Thiols …
Read More »Reduction of the Carbonyl group : Synthesis of Alcohols
Reduction of the Carbonyl group : Synthesis of 1° and 2° Alcohols – Grignard reagents convert carbonyl group to alcohols by adding alkyl groups. – Hydride reagents add a hydride ion (H:–) reducing the carbonyl group to an alkoxide ion with no additional carbon atoms. – Subsequent protonation gives the …
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