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Chapter

Cover Essentials of Human Nutrition

Alcohol  

A. Stewart Truswell

This chapter is about alcohol, which is the only substance that is both a drug affecting brain function and a nutrient. It begins by looking at the production of alcoholic beverages. Alcohol is produced by alcoholic fermentation of glucose; from the basic fermented beverages, alcohol becomes concentrated by the process of distillation. The chapter then considers the metabolism of alcohol and its effect on the brain. Pharmacologists classify ethanol as a central nervous system depressant, and it is in the same group as volatile anaesthetic agents. With increasing levels of blood alcohol, people pass through successive stages of alcohol intoxication. The chapter discusses the medical consequences of excess consumption of alcohol, examining coronary heart disease and alcoholism. It also investigates whether there is genetic liability to alcohol dependence.

Chapter

Cover Applied Organometallic Chemistry and Catalysis

Hydroformylation and related reactions  

This chapter focuses on hydroformylation, or the OXO (oxonation) reaction, which is used to describe the addition of CO and H2O to the C=C bond of an olefin or other unsaturated compounds. It talks about the synthesis of fatty alcohols from terminal olefins such as hept-l-ene. It also analyzes linear alcohols prepared by hydroformylation of mixtures of C12 olefins obtained by the controlled oligomerization of propylene, used in the synthesis of biodegradable detergents. The chapter deals with the bulk of productions via hydroformylation which involves relatively simple olefins. This is applied to a great variety of substituted olefins, both simple and complex. It illustrates several variations of olefin hydroformylation processes that have been commercialized.

Chapter

Cover Human Nutrition

Alcohol metabolism: implications for nutrition and health  

Vinood B. Patel and Victor R. Preedy

This chapter considers implications for nutrition and health in relation to alcohol metabolism. It shows how individuals will have a preference for consuming different types of alcoholic beverages, referencing some communities that forbid alcohol consumption on religious, cultural, or moral grounds. Acute and chronic consumption of alcohol may cause malnutrition or act as a toxin and induce pathological changes in a variety of organs and tissues. The chapter provides an overview into how alcohol damages virtually all organs in the body before detailing the principal nutritional deficiencies related to alcoholism. It looks into the causes associated with drinking in low socioeconomic status groups, and government policies to minimize alcohol consumption.

Chapter

Cover Bifunctional Compounds

Allyl compounds  

This chapter focuses on allyl alcohols, which are renowned for their ease of oxidation. It refers to manganese dioxide, which is highly effective for bringing about the oxidation of primary allylic alcohols to the αβ-unsaturated aldehydes. It also describes a highly-selective oxidation of allylic alcohols that involves epoxidation of the carbon-carbon double bond using tert-butyl hydroperoxide and a titanium or vanadium catalyst. The chapter analyses a valuable method of asymmetric synthesis known as Sharpless epoxidation, which involves treating the allylic alcohol with tert-butyl hydroperoxide in the presence of titanium tetraisopropoxide and a chiral ester of tartaric acid. This produces epoxy alcohols, which can be converted into a wide variety of other products by reduction or nucleophilic addition. The chapter also covers allyl ethers and allyl halides.

Chapter

Cover Making the Transition to University Chemistry

Alcohols  

This chapter focuses on alcohols (ROH) which have at least one hydroxyl group bonded to a carbon atom. Alcohols are known to undergo two reactions similar to the reactions of halogenoalkanes. Additionally, esters are formed through an alcohol's reaction to carboxylic acids. Alcohols also undergo oxidation reactions. The chapter explores the main manufacturing processes for ethanol which are fermentation and the direct hydration of ethene. It also considers the nucleophilic substitution and oxidation reactions of alcohols. The elimination reactions coincide with alcohol being dehydrated through heating with acid. However, conditions depend on the specific alcohol involved in the process as some of the alcohols could produce more than a single product.

Chapter

Cover Organic Chemistry

Reactions of Alcohols, Ethers, Thiols, Sulfides, and Amines  

This chapter examines the principal methods of preparation of alcohols. It emphasizes that the characteristic properties of alcohols originate in the hydroxy group. Protonation of the O in alcohols and ethers converts poor leaving groups, HO− and RO−, into good ones, H2O and ROH. The chapter then reveals that this enhancement of reactivity by protonation is another example of acid catalysis. The chapter also covers other examples such as acid-catalysed nucleophilic substitution and elimination reactions. In these reactions, R–OH2+ and R–O(H)R+ are comparable with haloalkanes. The chapter also explores the ring-opening reactions of epoxides (oxiranes). It then shifts to discuss the reactions of the sulfur analogues of alcohols (thiols, RSH) and of ethers (sulfides, RSR'), which may be regarded as derivatives of hydrogen sulfide, H2S. It concludes by explaining the reactions of amines.

Book

Cover Essentials of Human Nutrition

Jim Mann, A. Stewart Truswell, and Leanne Hodson

Essentials of Human Nutrition provides a comprehensive guide to human nutrition. The first part provides an introduction. Part 2 looks at energy and macronutrients, considering carbohydrates, lipids, protein, energy, and alcohol. Part 3 looks at organic and inorganic essential nutrients. The fourth part covers nutrition-related disorders such as obesity, protein-energy malnutrition, cardiovascular disease, cancer, diabetes, metabolic syndrome, and eating disorders. The fifth part looks at food groups and food toxicity and safety. Part 6 considers changing food habits. The seventh part is about various life stages and how they relate to nutrition, such as pre-pregnancy, pregnancy, lactation, infants, toddlers, childhood, adolescents, and aging. The next part looks at nutritional assessment. The last part talks about applications such as sport nutrition, poverty, food in hospitals, and hospital patients.

Chapter

Cover Making the Transition to University Chemistry

Aldehydes and Ketones  

This chapter describes aldehydes and ketones. Aldehydes have one alkyl group and one hydrogen atom attached to the carbonyl carbon. Ketones have two alkyl groups and resist oxidation. Both aldehydes and ketones contain the carbonyl group which has a carbon atom doubly bonded to an oxygen atom. Fehling's solution and Tollens' reagent can also help determine the differences between aldehydes and ketones. Oxidation can also help the reduction of aldehydes and ketones to primary and secondary alcohols respectively. The chapter also explains nucleophilic addition, condensation reactions, and alpha carbon reaction of aldehydes and ketones.

Book

Cover Human Nutrition

Catherine Geissler and Hilary Powers

Human Nutrition features chapters from global experts, covering a broad range of disciplines within the field of human nutrition. Part 1 covers food and nutrients, looking at food and nutrient patterns and structure. It also considers food safety. The second part looks at physiology and macronutrient metabolism. Here, chapters examine nutrient digestion and absorption, body size and composition, energy balance and body weight regulation, and carbohydrate metabolism. This part also covers fat metabolism, protein metabolism, and alcohol metabolism. The third part looks at micronutrient function and metabolism and describes water-soluble vitamins, fat-soluble vitamins, and minerals and trace elements. The next part moves to dietary requirements for specific groups such as in infancy, childhood, pregnancy, and for sport and exercise. Part 5, the largest part of the book, considers nutrition and disease. Diseases and conditions covered include obesity, diabetes, cancer, dental disease, and eating disorders. Part 6 provides and assessment of nutritional status. The final part is about public health nutrition. This edition contains new material covering food sustainability, the gut microbiome, dementia, the social impact of alcohol consumption, and the implications of climate change on food security. It also looks at emerging trends are highlighted and discussed, including global malnutrition and food safety policy. COVID-19 is discussed in the context of diet and nutritional status.

Chapter

Cover Organic Chemistry

Using organometallic reagents to make C–C bonds  

This chapter addresses one of the most important ways of making carbon–carbon (C–C) bonds: using organometallics, such as organolithiums and Grignard reagents, in combination with carbonyl compounds. Carbon dioxide reacts with organolithiums and Grignard reagents to give carboxylate salts. Protonating the salt with acid gives a carboxylic acid with one more carbon atom than the starting organometallic. Meanwhile, aldehydes and ketones react with organometallic reagents to form secondary and tertiary alcohols, respectively. The chapter then looks at the oxidation of alcohols. Oxidation of primary alcohols gives aldehydes and then carboxylic acids, while oxidation of secondary alcohols gives ketones. It is important to note that we cannot oxidize tertiary alcohols without breaking a C–C bond.

Chapter

Cover Organic Synthesis

Retrosynthetic analysis I: The basic concepts  

This chapter discusses the basic concepts of retrosynthetic analysis. When presented with a specific target molecule, a synthetic route must be designed which enables a pure sample of the desired product to be obtained using a convenient and efficient procedure. Chemists have developed a logical approach for the design of routes for the preparation of organic compounds which involves working the synthesis backwards by making strategic carbon–carbon bond cleavages at points where, in the forward reaction, bond forming reactions may be achieved. This is known as either the disconnection approach or retrosynthetic analysis. The fundamentals of the process of retrosynthetic analysis may be demonstrated by consideration of the synthesis of the secondary alcohol.

Chapter

Cover Organic Synthesis

Protection of hydroxy groups as silyl ethers  

This chapter illustrates the formation of silyl ethers. It gives attention to the trimethylsilyl group which has been used extensively for the protection of alcohols. One of the many methods which have been used for protecting a hydroxy group as its trimethylsilyl ether involves adding trimethylsilyl chloride (trimethylchlorosilane, TMCS) to the alcohol in the presence of a weak base. The chapter then argues that silyl ethers are cleaved to their parent alcohols by nucleophiles (often alcohols) under a range of acidic or basic conditions. Finally, the chapter shows some examples of protection of hydroxy groups as silyl ethers — emphasizing the synthesis of (R)-isoproterenol and the synthesis of gephyrotoxin.

Chapter

Cover Organic Synthesis

Allylboranes and boron enolates  

This chapter considers allylboranes in organic synthesis. Focusing on the stability of allylboranes, the chapter displays how allyldialkylboranes can be used in further reactions if either they are prepared and used directly at low temperature, or the predominant isomer at equilibrium is the required isomer. The chapter also discusses the reaction of allylboranes with carbonyl compounds. It examines how triallylboranes react with aldehydes and ketones to give, on hydrolysis, homoallylic alcohols. The chapter then investigates the synthesis of homochiral homoallylic alcohols containing one chiral centre, and the synthesis of homoallylic alcohols containing two chiral centres. It ends with a discussion of boron enolates in organic synthesis.

Chapter

Cover Functional Groups

Organometallic compounds  

This chapter covers the most useful organometallic compounds R-M with M = Li, Mg, or Cd, including Zn compounds and lithium cuprates. It illustrates the main features of R-Mg-Hal as reagents in synthetic work and reactions that produce Mg derivatives from which the products are liberated by a treatment with dilute acid. It also discusses the reactions with esters that result in ketones or aldehydes, which cannot be isolated under standard conditions. The chapter refers to the instability of intermediates, which is are not readily predicted by organic theory and stems from the decrease of free energy associated with their decompositions. It highlights the formation of the tertiary alcohol in high yield by R-Li, which provides a sharp contrast and exemplifies the modern trends towards the use of reagents.

Chapter

Cover Bifunctional Compounds

Selective protection of bifunctional compounds  

This chapter addresses a problem which frequently arises with a molecule that contains two reactive functional groups: how can one carry out a selective reaction on one group without affecting the other? It clarifies how acetals can be used to protect aldehyde or ketone groups while transformations are carried out elsewhere in a molecule. It also implies that acetals can be used to protect diols and simple alcohols, noting that they are often preferable to simple ether protecting groups as they can be removed under very mild conditions. The chapter points out that tetrahydropyranyl and methoxymethyl ethers are actually acetals that can be easily removed via treatment with aqueous acid. The chapter also covers the selective protection and deprotection of carbohydrates and amino acids.

Chapter

Cover Carbohydrate Chemistry

Reactions of hydroxyl groups Part I  

This chapter describes the types of hydroxyl groups found in sugars and points out that carbohydrates exist in cyclic forms of hemiacetals. It highlights the importance of the reaction of the hydroxyl groups. This reaction allows for regioselective reactions of those groups left unprotected. The chapter also analyses the products of acetylations under different conditions and give examples of methods that are used to protect the c of a sugar. The chapter reviews the methods for forming and cleaving ether, such as benzyl, trityl, and silyl, and ester, such as acetate, benzoate, and sulfonate to protect groups. It talks about the difficulties associated with the substitution of sugar hydroxyl groups.

Chapter

Cover Core Carbonyl Chemistry

Acetals and ketals  

This chapter examines acetals and ketals. Aldehydes and ketones react reversibly 1:1 with alcohols under general acid or general base catalysis, to give hemiacetals and hemiketals, respectively. With excess alcohol and a catalytic amount of a strong acid, further reversible reaction takes place to replace the OH group and give an acetal (from an aldehyde) or ketal (from a ketone). If arrangements are made to remove the water from the continuously equilibrating mixture, by distillation or other means, then the aldehyde or ketone is quantitatively converted to an acetal or ketal, as the case may be. The reaction proceeds more easily with aldehydes than with ketones, and is practically limited to primary alcohols. The chapter then looks at dithioacetals, dithioketals, and orthoesters. It also considers the protecting group principle.

Chapter

Cover Protecting Group Chemistry

Silyl protecting groups  

This chapter evaluates silyl protecting groups. To categorise silicon protecting groups as either acid or base-labile is impractical because both types of cleavage are possible and find routine use. Organosilicon chemistry is characterised by a high affinity for oxygen, which has led to the widespread use of silyl ethers for the protection of alcohols, and higher affinity for fluorine, which provides a very selective deprotection pathway. The chapter then looks at alcohols, diols, aldehydes and ketones, and amines. Deprotection of silyl protecting groups with F-ion is normally highly selective but the basic properties of the hydrated ion in solution can interfere with functionality not containing silicon and can lead to unexpected reactions.

Chapter

Cover How to Succeed in Organic Chemistry

Building Skills  

This chapter presents a series of worked problems within organic chemistry that vary in scope and complexity and require the basic application of knowledge to predict the outcomes of reaction. It includes activities that require the drawing of correct curly arrows showing either a substitution or an elimination reaction. It also presents a question on whether it is possible for all nine C–H bonds in the t-butyl carbocation to simultaneously overlap with the vacant p orbital. The chapter reviews the thermodynamics of reactions involving charged species and considers the implications of acid catalysis with a strong acid and a weak acid. It compares two processes that established that the activation energy from the protonated alcohol is significantly lower.

Chapter

Cover Aromatic Chemistry

Aromatic compounds  

This chapter assesses aromatic compounds. Alkenylbenzenes are normally synthesized through the dehydration of arylalkanols, or by the dehydrohalogenation of arylalkyl halides. The best known alkenylarene, ethenylbenzene (styrene), is obtained commercially from benzene in two steps: first, alkylation with ethene in the presence of an acid or a Lewis acid, and second, dehydrogenation of the product, ethylbenzene, by heating over a catalyst at 600°C. Styrene undergoes radical initiated polymerization with itself, to form polystyrene, or with other molecules to form copolymers; both processes have important commercial applications. The chapter then looks at aromatic halides; aromatic alcohols; aromatic carbonyl compounds; and aromatic acids, esters, and amides. It also considers aromatic sulfonic acids, nitro compounds and reduction products, aromatic amines, and phenols.