Unsaturated aliphatic halogen compounds

Alberti and Jonke [60] describe a gas chromatographic method for the determination of vinyl chloride in surface waters using a flame ionisation detector and a Poropak Q or Chromosorb 101 column. The detection limit is 0.3mg L and samples of waste waters from vinyl chloride or PVC factories can be irqected direct into the gas chromatograph, while water samples with lower concentrations require preliminary eruichment for which a gradient-tube method is described. 

Source Reproduced by permission from Elsevier Science, UK [57] 

In the direct gas chromatographic method [62] vinyl chloride, arenes and other volatile halogen compovmds are separated from the water sample by stripping them in a closed system. The stripped compoimds were absorbed on Poropak N in a glass tube within the closed system and eluted with methanol. They were then separated by gas chromatography on a 3m Chromosorb 102 column. The solvent is compatible with either 

Other applications of gas chromatography to the determination of unsaturated aliphatic halogen compounds in non saline waters are discussed in Table 15.9. 

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It is only in relatively recent years that the interaction of indole Grignard reagents with unsaturated aliphatic halogen compounds has... 

There has been a growing interest in applying high performance liquid chromatography, to the determination of the not only volatile compounds, such as aliphatic and polyaromatic hydrocarbons, saturated and unsaturated aliphatic and polyaromatic hydrocarbons, saturated and unsaturated aliphatic halogen compounds, haloforms and some esters, phenols and others but also non volatile components of water. 

In unsaturated aliphatic systems the most important reactions are those of czirbonyl compounds of the type —COX, in which X is a good leaving group such as halogen. In general, most displacement reactions of anionic nucleophiles on the carbonyl carbon atom of acyl halides involve an addition-elimination mechanism " (e.g. equation 16). In such reactions bond-formation is in advance of bond-rupture... 

Applicability Particularly accurate for the following families acetates, aliphatic ethers, halogenated compounds, dicarboxylic acids, ketones, aliphatic alcohols, aliphatic acids, propionates and butyrates, and unsaturated aliphatic esters. 

As shown in Figure 4.1, there are additional reactive sites in phospholipids that potentially may be halogenated in the presence of peroxidase-derived hypohalous acids. In 1998, studies by Winterbourne et al. showed both hypochlorous acid and hypobromous acids react with both unsaturated aliphatic residues and the ethanol-amine of phosphatidylethanolamine (Carr et al. 1998). These studies showed that the amine was more reactive than alkenes and that the alkenes formed halohydrins only after the amine was consumed by the hypohalous acid. This was similar to the findings with plasmalogens which showed the chlorohydrins were only produced once the vinyl ether bond was consumed. Additionally these earlier studies demonstrated that bromoamine was reactive in producing bromohydrins, and this activity was greater than that observed with chloramines (Carr et al. 1998). Others have also shown the reactivity of hypohalous acids with ethanolamine (Jaskolla et al. 2009), but it is unclear whether these compounds are stable in cells or in vivo. 

The organization is fairly classical, with some exceptions. After an introductory chapter on bonding, isomerism, and an overview of the subject (Chapter 1), the next three chapters treat saturated, unsaturated, and aromatic hydrocarbons in sequence. The concept of reaction mechanism is presented early, and examples are included in virtually all subsequent chapters. Stereoisomerism is also introduced early, briefly in Chapters 2 and 3, and then given separate attention in a fuU chapter (Chapter 5). Halogenated compounds are used in Chapter 6 as a vehicle for introducing aliphatic substitution and elimination mechanisms and dynamic stereochemistry. 

This topic has been reviewed [2, pp 94, 100-111, 130-134] All of the standard approaches to the synthesis of a compound like methyl 2-fluorostearate from methyl 2-bromostearate result mall yield of the 2-fluoro ester and the unsaturated esters. Although silver fluoride is not a new reagent, its use moist in wet acetonitrile to convert methyl 2-bromostearate to its fluoro ester is a departure from the traditional set of anhydrous conditions (Procedure 6, p 194) [71] In contrast, silver tetrafluoroborate converts a-chloroketones to their respective fluoroketones under anhydrous conditions. The displacement of less activated halogen groups by silver tetrafluoroborate to form their respective fluorides is novel Although silver tetrafluoroborate could not be used to convert an aliphatic terminal dichloromethyl or trichloromethyl group to its corresponding fluoro derivative, it is an effective fluorine source in other situations [72] (Table 8)... 

The lower members of the homologous series of 1. Alcohols 2. Aldehydes 3. Ketones 4. Acids 5. Esters 6. Phenols 7. Anhydrides 8. Amines 9. Nitriles 10. Polyhydroxy phenols 1. Polybasic acids and hydro-oxy acids. 2. Glycols, poly-hydric alcohols, polyhydroxy aldehydes and ketones (sugars) 3. Some amides, ammo acids, di-and polyamino compounds, amino alcohols 4. Sulphonic acids 5. Sulphinic acids 6. Salts 1. Acids 2. Phenols 3. Imides 4. Some primary and secondary nitro compounds oximes 5. Mercaptans and thiophenols 6. Sulphonic acids, sulphinic acids, sulphuric acids, and sul-phonamides 7. Some diketones and (3-keto esters 1. Primary amines 2. Secondary aliphatic and aryl-alkyl amines 3. Aliphatic and some aryl-alkyl tertiary amines 4. Hydrazines 1. Unsaturated hydrocarbons 2. Some poly-alkylated aromatic hydrocarbons 3. Alcohols 4. Aldehydes 5. Ketones 6. Esters 7. Anhydrides 8. Ethers and acetals 9. Lactones 10. Acyl halides 1. Saturated aliphatic hydrocarbons Cyclic paraffin hydrocarbons 3. Aromatic hydrocarbons 4. Halogen derivatives of 1, 2 and 3 5. Diaryl ethers 1. Nitro compounds (tertiary) 2. Amides and derivatives of aldehydes and ketones 3. Nitriles 4. Negatively substituted amines 5. Nitroso, azo, hy-drazo, and other intermediate reduction products of nitro com-pounds 6. Sulphones, sul-phonamides of secondary amines, sulphides, sulphates and other Sulphur compounds... 

Volume 9 deals with the majority of addition and elimination reactions involving aliphatic compounds. Chapter 1 covers electrophilic addition processes, mainly of water, acids and halogens to olefins and acetylenes, and Chapter 2 the addition of unsaturated compounds to each other (the Diels-Alder reaction and other cycloadditions). This is followed by a full discussion of a-, y- and S-eliminations (mainly olefin and alkyne forming) and fragmentation reactions. In Chapter 4 carbene and carbenoid reactions, and in Chapter 5 alkene isomerisation (including prototropic and anionotropic, and Cope and Claisen rearrangements), are discussed. 

The reactive halogenated flame-retardants are unsaturated monomers or functional aromatic and aliphatic compounds. The most important materials are listed in Table 5.5. 

Initial pyrolysis reactions of halogen-containing compounds generally lead to the formation of HX and RX but seldom to the formation of X2, where X is a halogen atom. Detachment of HX from the aliphatic structured macromolecules is accompanied mostly by the formation of unsaturated systems. Transformation of these systems inside the condensed phase causes the formation of a nonvolatile carbonized residue which, in the long run, affects the rate of combustion of the materials. 

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