Section 3 Glycol ethers

Butoxyethanol and 2-butoxycthanol acetate may be released to water by facilities that manufacture, process, or use these compounds in the production of other materials (see Sections 4.1 and 4.3). Information on releases to water from facilities that manufacture or process 2-butoxyethanol is not available in the TRI database because the database contains such information only for the general toxic chemical category of glycol ethers and not for specific glycol ethers (EPA 1995). No information is available in the TRI database on the amount of 2-butoxyethanol acetate released to water by facilities that manufacture or process this compound because this compound is not included under SARA, Title III it is therefore not among tlie chemicals that facilities are required to report (EPA 1995). 

A search of tlie Federal Research in Progress database (FEDRIP 1995) indicates that no research studies are in progress to fill the data gaps discussed in Section 5.7.1. The Consumer Products Safety Commission is working on a report concerning the uses of ethylene glycol ethers including 2-butoxyethanol. 

The most extensive group of ether surfactants is that of polyethoxylated long-chain alcohols and related ethoxylated products considered, in view of their practical importance, in a separate section. Other ether nonionics of importance are polypropylene glycols, propoxylated alcohols, block-copolymers of ethylene oxide and propylene oxide, block-copolymers of ethylene oxide and butylene oxide [8, 16-20], block-copolymers having a hydrophobic polydimethylsiloxane moiety [19, 21], as well as alkyl polyglycerides, alkyl polyglycosides, derivatives of maltose and other saccarides. 

Individual compounds in air, water, or wastes may be analyzed by common instrumental techniques such as gas chromatography using a flame ionization detector. Other techniques, such as HPLC and GC/MS, are equally suitable. Any column that is efficient for the separation of alcohols may be used to analyze glycol ethers. Analysis of some of these compounds is discussed in greater detail in the sections on individual compounds. 

Electrophoretic coatings are similar to those used and described in section 8.2 on automotive OEM coatings. Metallic (conductive) substrates are essential if this technique is to be used successfully. Water is obviously the main solvent to achieve the degree of conductivity needed, but significant quantities of solvents such as the glycol ethers are needed to solubilise the resins used and to produce the quality of film finish required. 

Other important aliphatic ethers include ethylene and propylene glycol ether that form from the respective epoxide hy water addition (see Section 6.12 for details) and methyl tert-butyl ether (MTBE) that is obtained from condensation of methanol and isobutanol or by addition of methanol to isobutene. 

Ethylene oxide A Ethylene glycol, glycol ethers poly(elhylene glycols), non-ionic tensides, ethanolamine 18 in 2005 (see Section 6.12)... 

This part of the handbook focuses on organic solvents. Speciflc information covered includes physical and chemical properties, typical uses, pertinent legislation, and selection criteria. The important solvent classes covered in this section include aldehydes, aliphatic and aromatic hydrocarbons, ethers, halogenated hydrocarbons, ketones, nitroparaffins, monohydric and polyhydric alcohols, glycol ethers, aliphatic and heterocyclic amines, esters, and some miscellaneous organic solvents. 

There will be considerable discussion of glycol ether ester plasticizers under the application section for polar elastomers. This group of plasticizers is the most polar of all and along with polymeries is probably the most important for purposes of this chapter. 

Oleophilic/oleophobic fluorinated surfactants without a hydrophile, designed for use in hydrocarbon systems, are in a structural sense also nonionic fluorinated surfactants (see Section 1.8) for example, the semifluorinated alkanes [266-270], block polyethylene-polypropylene glycol ethers prepared with perfluoroalkene trimers [271], surfactants featuring an oligo(hexafluoropropene oxide) chain [272], and carboxamides and sulfonamides derived from A -(perfluorooctanesul-fonyl)piperazine [273]. 

Hexamethylene glycol, HO(CH2)gOH. Use 60 g. of sodium, 81 g. of diethyl adipate (Sections 111,99 and III,100) and 600 ml. of super-d ethyl alcohol. All other experimental detaUs, including amounts of water, hydrochloric acid and potassium carbonate, are identical with those for Telramelhylene Glycol. The yield of hexamethylene glycol, b.p. 146-149°/ 7 mm., is 30 g. The glycol may also be isolated by continuous extraction with ether or benzene. 

Epoxides are cleaved by treatment with acid just as other ethers are, but under much milder conditions because of ring strain. As we saw in Section 7.8, dilute aqueous acid at room temperature is sufficient to cause the hydrolysis of epoxides to 1,2-diols, also called vicinal glycols. (The word vicinal means "adjacent/ and a glycol is a diol.) The epoxide cleavage takes place by SK2-like backside attack of a nucleophile on the protonated epoxide, giving a trans- 1,2-dio) as product. 

Acetalization or ketalization with silylated glycols or 1,3-propanediols and the formation of thioketals by use of silylated 1,2-ethylenedithiols and silylated 2-mer-captoethylamines have already been discussed in Sections 5.1.1 and 5.1.5. For cyclizations of ketones such as cyclohexanone or of benzaldehyde dimethyl acetal 121 with co-silyl oxyallyltrimethylsilanes 640 to form unsaturated spiro ethers 642 and substituted tetrahydrofurans such as 647, see also Section 5.1.4. (cf. also the reaction of 654 to give 655 in Section 5.2) Likewise, Sila-Pummerer cyclizations have been discussed in Chapter 8 (Schemes 8.17-8.20). 

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