Alkyl sulfates conversion

Mono- and dialkyl derivatives can also be prepared using alkyl sulfates. Aryl chlorides are usually inert, unless activated by an electron-withdrawing group. Conversion to alkoxides allows formation of ethers. 

Alkyl sulfates, tosylates, and other esters of sulfuric and sulfonic acids can be converted to alkyl halides with any of the four halide ions.979 Neopentyl tosylate reacts with Cl, Br, or I without rearrangement in HMPA.980 Similarly, allylic tosylates can be converted to chlorides without allylic rearrangement by reaction with LiCl in the same solvent.981 Inorganic esters are intermediates in the conversion of alcohols to alkyl halides with SOCl2, PC15, PC13, etc. (0-67), but are seldom isolated. 

In fact, the reaction of alkoxides with alkyl halides or alkyl sulfates is an important general method for the preparation of ethers, and is known as the Williamson synthesis. Complications can occur because the increase of nucleo-philicity associated with the conversion of an alcohol to an alkoxide ion always is accompanied by an even greater increase in eliminating power by the E2 mechanism. The reaction of an alkyl halide with alkoxide then may be one of elimination rather than substitution, depending on the temperature, the structure of the halide, and the alkoxide (Section 8-8). For example, if we wish to prepare isopropyl methyl ether, better yields would be obtained if we were to... 

The effect of increasing the hydrocarbon chain length from methyl to octadecyl on the acid catalyzed, neutral, and base catalyzed hydrolysis of n-alkyl sulfate esters has been examined (Kurz, 1962). The rate constants for the neutral hydrolysis decrease smoothly from methyl to dodecyl sulfate and hence are unaffected by micellization of the longer chain esters. The rate constants for the acid-catalyzed hydrolysis, however, are relatively constant for the non-micellar ester but increase dramatically with micelle formation (Table 7). Conversely, the hydroxide... 

The effects of increasing the concentration of initiator (i.e. increased conversion, decreased and broader PDi) and reducing the reaction temperature (i.e. decreased conversion, increased M and narrower PDi) for the polymerizations in ambient-temperature ionic Uquids are the same as observed in conventional solvents. Mays et al. reported similar results and, in addition, used NMR to investigate the stereochemistry of the PMMA produced in (BMIMjlPFej. They found that the stereochemistry is almost identical to that for PMMA produced by free radical polymerization in conventional solvents [28]. The homopolymerization and copolymerization of several other monomers are also reported. Similar to vdiat was found by Noda and Watanabe, in many cases the polymer was not soluble in the ionic liquid and thus phase separated [28,29]. Free radical polymerization of n-butyl methacrylate in ionic liquids based on imidazolium, pyridinium, and alkylammonium salts as solvents was investigated with a systematic variation of the length of the alkyl substituents on the cations, and employing different anions such as tetrafluoroborate, hexafluorophosphate, tosylate, triflate, alkyl sulfates and dimethyl phosphate [31]. 

The use of chlorosulfonic acid (1.5-1.6 equivalents) converted petroleum-derived unsaturated alcohols (one equivalent) into alkyl sulfates (92% conversion) with good surfactant properties. ... 

Fig. 1. Sulfonated and sulfated acid products viscosities after 98% conversions at varying temperatures where the vertical line indicates the maximum temperature for batch sulfonation using SO to minimi2e color deterioration lines A—C represent branched C 2 alkyl ben2ene (BAB) sulfonic acid from SO, oleum (settied), and oleum (whole mixture), respectively lines D and E, lauryl alcohol 3-ethoxylate sulfuric ester (SO ) and lauryl alcohol sulfuric ester...

Internal Sizing. The most widely used internal sizes are alkyl ketene dimers (AKD), alkenylsuccinic anhydrides (ASA), and rosin-based sizes that are used with papermaker s alum (aluminum sulfate with 14 waters of hydration), polyaluminum chloride (PAG), or polyaluminum siUcosulfate (PAS) (61). The rosin-based sizes are used under acidic conditions. Since the mid 1980 s there has been a steady conversion from acid to alkaline paper production, resulting in static to declining demand for the rosin-based sizing systems. Rosin is a complex mixture of compounds and consists primarily of monocarboxyhc acids with alkylated hydrophenan threne stmctures (62). A main constituent of wood rosin, gum rosin and taH-oil rosin is abietic acid. 

The straightforward construction of substituted pyrone 4 proceeded as follows (see Scheme 6c). Alkylation of the monoanion of 2,4-pentanedione (8) with methyl iodide furnishes 3-methyl-2,4-pentanedione. Conversion of this substance into the corresponding dianion with sodium amide followed by selective carboxylation of the more basic site provides intermediate 7. Pyrone 4 is obtained after cyclization with l,l -carbonyldiimidazole and methylation of the resulting enol with dimethyl sulfate. 

A variety of solid acids besides zeolites have been tested as alkylation catalysts. Sulfated zirconia and related materials have drawn considerable attention because of what was initially thought to be their superacidic nature and their well-demonstrated ability to isomerize short linear alkanes at temperatures below 423 K. Corma et al. (188) compared sulfated zirconia and zeolite BEA at reaction temperatures of 273 and 323 K in isobutane/2-butene alkylation. While BEA catalyzed mainly dimerization at 273 K, the sulfated zirconia exhibited a high selectivity to TMPs. At 323 K, on the other hand, zeolite BEA produced more TMPs than sulfated zirconia, which under these conditions produced mainly cracked products with 65 wt% selectivity. The TMP/DMH ratio was always higher for the sulfated zirconia sample. These distinctive differences in the product distribution were attributed to the much stronger acid sites in sulfated zirconia than in zeolite BEA, but today one would question this suggestion because of evidence that the sulfated zirconia catalyst is not strongly acidic, being active for alkane isomerization because of a combination of acidic character and redox properties that help initiate hydrocarbon conversions (189). The time-on-stream behavior was more favorable for BEA, which deactivated at a lower rate than sulfated zirconia. Whether differences in the adsorption of the feed and product molecules influenced the performance was not discussed. 

Figure 13.6 Variation of both the conversion of 2-butene and the selectivity to trimethyl-pentanes (TMP), with the nature of the metal oxide support obtained during the isobutene/ 2-butene alkylation at 32°C over sulfated supported on different metal oxides. (After Ref. 35.)...

Figure 13.7 Conversion of 2-butene and the selectivities to cracking products, TMP, and C9+ hydrocarbons during the isobutane alkylation at 50°C on nafion/Si02 (NS-1), sulfated zirconia (SZ), and MCM-41-supported 12-tungstophosphoric acid (HPW/MCM). Experimental conditions T = 32 C TOS = 1 min molar ratio of 15.

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