Tri ethers

These selectivities obtained with Amberlyst-15 seem to be rather optimistic in view of recent work, where only with overstoichiometric ratios high di-+tri-ether selectivity is obtained. It is also not settled why addition of tert-butanol to the reaction mixture suppresses isobutene oligomerization selectivity [34, 35], At this stage it should also be stressed that the tert-butylglycerol ethers (TBGE) mentioned are excellent substitutes for MTBE (ETBE) as gasoline octane boosting components [36]. 

The highly hydrophilic alcohols, pentaerythritol and 2-ethyl-2-hydroxymethyl-propan-l,3-diol, can be converted into their corresponding ethers in good yields under phase-transfer catalytic conditions [12]. Etherification of pentaerythritol tends to yield the trialkoxy derivative and kinetics of the reaction have been shown to be controlled by the solubility of the ammonium salt of the tris-ether in the organic phase and the equilibrium between the tris-ether and its sodium salt [13]. Total etherification of the tetra-ol is attained in good yield when reactive haloalkanes are used, and tetra-rt-octylammonium, in preference to tetra-n-butylammonium, bromide [12, 13]. 

Sugar Ligand Conversion (%) Selectivity (%) Mono-ethers Diethers Tri-ethers... 

Phosphorus-31 NMR has also been employed in identifying fluxionalities of various metal phosphine complexes. Bis- and tris-(ether phosphine) ruthenium(II) chloro and acetato complexes exhibit exchange between the... 

When the MD-P2P/crap oil has been isolated and is at the point where one would normally apply distillation, this is the point where the chemist will use the bisulfite. One should not try this method unless the oil is rid of most solvent. In the Method 1 above, one would apply it after the ether from the final extraction has been removed by boiling or distillation (Yes, some distillation still ap-... 

Both reactants m the Williamson ether synthesis usually originate m alcohol pre cursors Sodium and potassium alkoxides are prepared by reaction of an alcohol with the appropriate metal and alkyl halides are most commonly made from alcohols by reaction with a hydrogen halide (Section 4 7) thionyl chloride (Section 4 13) or phosphorus tri bromide (Section 4 13) Alternatively alkyl p toluenesulfonates may be used m place of alkyl halides alkyl p toluenesulfonates are also prepared from alcohols as their imme diate precursors (Section 8 14)... 

ECF is successfully used on a commercial scale to produce certain perfluoroacyl fluorides, perfluoroalkylsulfonyl fluorides, perfluoroalkyl ethers, and perfluoroalkylamines. The perfluoroacyl fluorides and perfluoroalkylsulfonyl fluorides can be hydrolyzed to form the corresponding acid and acid derivatives. Examples include perfluorooctanoyl fluoride [335-66-0] perfluorooctanoic acid [335-67-1] perfluorooctanesulfonyl fluoride [307-35-7] perfluorooctanesulfonic acid [763-23-1] and tris(perfluoro- -butyl)amine [311-89-7]. 

Many organic reagents have been used successfully in Pu separation processes. The reagents include tri- -butyl phosphate (TBP) methyl isobutyl ketone thenoyl ttifluoroacetone (TTA) ethers, eg, diethyl ether, di- -butyl ether, tetraethylene glycol dibutyl ether trdaurylamine (TT,A) trioctylamine (TOA) di- -butyl phosphate (DBP) hexyl-di(2-ethylhexyl) phosphate (HDEHP) and many others. Of these, TBP is by far the most widely used (30,95). 

Formulas for representative floor poHshes are Hsted in References 3, 12, 13, and 25. An aqueous formula may contain 0—12 wt % polymer, 0—12 wt % resin, 0—6 wt % wax, 0.3—1.5 wt % tris(butoxyethyl)phosphate, 1—6 wt % glycol ether, and 0—1 wt % zinc, with water filling the rest. Water-clear floor finishes contain Htfle or no wax, whereas buffable products contain relatively large amounts of wax. Sealers contain Htfle wax and relatively large amounts of emulsion polymers (28). For industrial use, sealers are appHed to porous substrates to fiH the pores and prevent poHshes that are used as topcoats from soaking into the floor. 

An important mode of oxidation for -phenylenediamines is the formation of ben2oquinonediimines, easily obtained by oxidation with silver oxide in ether solution (17). DHmines undergo 1,4 additions with amines to generate tri- and tetraamines which readily oxidi2e in air to highly conjugated, colored products. An example of this is the formation of Bandrowski s base [20048-27-5] when -phenylenediamine is oxidi2ed with potassium ferricyanide (18). 

The principal solvents that have been used are alcohols such as ethanol, methanol, and propanol, and organic acids such as formic or acetic acid, but other solvents iaclude esters, ethers, phenols, cresols, and some amines. Even solvents such as CO2 and NH in the supercritical fluid state have been tried as solvents. 

Trityl Ethers. Treatment of sucrose with four molar equivalents of chlorotriphenylmethyl chloride (trityl chloride) in pyridine gives, after acetylation and chromatography, 6,1, 6 -tri-O-tritylsucrose [35674-14-7] and 6,6 -di-O-tritylsucrose [35674-15-8] in 50 and 30% yield, respectively (16). Conventional acetylation of 6,1, 6 -tri-O-tritylsucrose, followed by detritylation and concomitant C-4 to C-6 acetyl migration using aqueous acetic acid, yields a pentaacetate, which on chlorination using thionyl chloride in pyridine and deacetylation produces 4,l, 6 -trichloro-4,l, 6 -trideoxygalactosucrose [56038-13-2] (sucralose), alow calorie sweetener (17). 

StericaHy hindered silyl ethers such as ferZ-hutyl dimethyl silyl, / fZ-butyldiphenylsilyl, and tricyclohexylsilyl have been proposed as alternatives to trityl ethers. Reaction of sucrose with 3.5 molar equivalents of ferZ-hutyl dimethyl silyl chloride produces the 6,1/6 -tri-O-silyl derivative in good yield (27). 

Bromine monofluoride [13863-59-7], BrF, can be prepared by the direct reaction of Br2 and F2, but because it readily disproportionates it has never been prepared in pure form (57). However, BrF can be prepared in situ by the reaction of Br2 with AgF in benzene (58) or by the reaction of A/-bromoacetamide and HF in ether (59). BrF adds to simple alkenes at room temperature to give products of trans-addition. Bromine trifluoride [7787-71-5], BrF, can be formed from gaseous fluorine and Hquid bromine (60). Bromine pentafluoride [7789-30-2], BrF, is formed from the reaction of BrF vapor with gaseous fluorine at 200°C (60). The tri- and pentafluorides are commercially available. As strong fluorinating agents they are useful in... 

Reagents, such as tri alkyl aluminums (90) and sodium benzophenone (109), are quite useful as reducing agents. Alkyl aluminums have been used to synthesize Cr(CO), Mo(CO), and W(CO) in high yields (90). In one case, hydrogen was used effectively as a reducing agent in petroleum ether solvent (110,111). 

---