Dimethyl sulfate, reaction with

Dimethylpiienylthiourea, 46, 70 Dimethylphosphine, 46, 103 Dimethylphosphimc acid, 46, 103 Dimethylphosphinyl chloride, 46, 103 Dimethyl sulfate, reaction with di-... 

Dimethyl sulfate, reaction with di-methylformamide, 47, 52 Dimethyl sulfoxide, in synthesis of phenyl f-butyl ether, 45, 89 potassium salt, preparation, 48, 109, 110... 

SuIfona.tlon, Sulfonation is a common reaction with dialkyl sulfates, either by slow decomposition on heating with the release of SO or by attack at the sulfur end of the O—S bond (63). Reaction products are usually the dimethyl ether, methanol, sulfonic acid, and methyl sulfonates, corresponding to both routes. Reactive aromatics are commonly those with higher reactivity to electrophilic substitution at temperatures > 100° C. Tn phenylamine, diphenylmethylamine, anisole, and diphenyl ether exhibit ring sulfonation at 150—160°C, 140°C, 155—160°C, and 180—190°C, respectively, but diphenyl ketone and benzyl methyl ether do not react up to 190°C. Diphenyl amine methylates and then sulfonates. Catalysis of sulfonation of anthraquinone by dimethyl sulfate occurs with thaHium(III) oxide or mercury(II) oxide at 170°C. Alkyl interchange also gives sulfation. 

In the method of Bredereck for permethylation of carbohydrates, partially methylated material is dissolved in ether, sodium wire is added followed by dimethyl sulfate diluted with ether. The reaction is complete in about one hour. 

Veratric aldehyde has been prepared from vanillin by methyl-ation with dimethyl sulfate or with methyl iodide, and from veratrole by reaction with hydrogen cyanide in the presence of aluminum chloride. ... 

Dissolve 2 g sodium hydroxide into 30 mL deionized water which contained 10 g /3-CD. Then add 5mL dimethyl sulfate slowly with stirring. Keep reaction system at 60°C for 8h. After that, cool the reaction buffer and adjust to neutral using diluted HCl. Then remove anions and cations through ion exchange resins (repeat 2 or 3 times). Concentrate the collected liquid to a syrup-like state by vacuum distillation. Finally, disperse the product in 40 mL acetone and vacuum dry to get the product. 

Based on the analysis and comparison of the mentioned chemical reactions, it can be known that 0 In the main reaction, it is easy to produce methyl nitrite, which makes it difficult to increase the total yield the product is not stable under acidic conditions 0 dimethyl sulfate is very easy to decompose into methanol under acidic and basic conditions 0 dimethyl sulfate reacts with sodium nitrite through two steps, in which the first step is the conversion of dimethyl sulfate into the intermediate methyl sulfonate followed by the higher energy-required reaction between methyl sulfonate and sodium nitrite, thus, in this step, the formation of byproduct methanol should be minimized through the hydrolysis of acid and base. 

These salts can be prepared by a four-step sequence (mediylation with dimethyl sulfate, treatment with fluoroboric acid, reduction with s um borohydide and reaction with fluoroboric add) [, [39]. 

Fats, Oils, or Fatty Acids. The primary products produced direcdy from fats, oils, or fatty acids without a nitrile iatermediate are the quatemized amidoamines, imidazolines, and ethoxylated derivatives (Fig. 3). Reaction of fatty acids or tallow with various polyamines produces the iatermediate dialkylarnidoarnine. By controlling reaction conditions, dehydration can be continued until the imidazoline is produced. Quaternaries are produced from both amidoamines and imidazolines by reaction with methyl chloride or dimethyl sulfate. The amidoamines can also react with ethylene oxide (qv) to produce ethoxylated amidoamines which are then quaternized. 

Etherification. The reaction of alkyl haUdes with sugar polyols in the presence of aqueous alkaline reagents generally results in partial etherification. Thus, a tetraaHyl ether is formed on reaction of D-mannitol with aHyl bromide in the presence of 20% sodium hydroxide at 75°C (124). Treatment of this partial ether with metallic sodium to form an alcoholate, followed by reaction with additional aHyl bromide, leads to hexaaHyl D-mannitol (125). Complete methylation of D-mannitol occurs, however, by the action of dimethyl sulfate and sodium hydroxide (126). A mixture of tetra- and pentabutyloxymethyl ethers of D-mannitol results from the action of butyl chloromethyl ether (127). Completely substituted trimethylsilyl derivatives of polyols, distillable in vacuo, are prepared by interaction with trim ethyl chi oro s il an e in the presence of pyridine (128). Hexavinylmannitol is obtained from D-mannitol and acetylene at 25.31 MPa (250 atm) and 160°C (129). 

All lation. In alkylation, the dialkyl sulfates react much faster than do the alkyl haHdes, because the monoalkyl sulfate anion (ROSO ) is more effective as a leaving group than a haHde ion. The high rate is most apparent with small primary alkyl groups, eg, methyl and ethyl. Some leaving groups, such as the fluorinated sulfonate anion, eg, the triflate anion, CF SO, react even faster in ester form (4). Against phenoxide anion, the reaction rate is methyl triflate [333-27-7] dimethyl sulfate methyl toluenesulfonate [23373-38-8] (5). Dialkyl sulfates, as compared to alkyl chlorides, lack chloride ions in their products chloride corrodes and requires the use of a gas instead of a Hquid. The lower sulfates are much less expensive than lower bromides or iodides, and they also alkylate quickly. 

Carbon is alkylated ia the form of enolates or as carbanions. The enolates are ambident ia activity and can react at an oxygen or a carbon. For example, refluxing equimolar amounts of dimethyl sulfate and ethyl acetoacetate with potassium carbonate gives a 36% yield of the 0-methylation product, ie, ethyl 3-methoxy-2-butenoate, and 30% of the C-methylation product, ie, ethyl 2-methyl-3-oxobutanoate (26). Generally, only one alkyl group of the sulfate reacts with beta-diketones, beta-ketoesters, or malonates (27). Factors affecting the 0 C alkylation ratio have been extensively studied (28). Reaction ia the presence of soHd Al O results mosdy ia C-alkylation of ethyl acetoacetate (29). 

Carbanions ia the form of phenyllithium, sodium naphthalene complex, sodium acetyHde, or aromatic Grignard reagents react with alkyl sulfates to give a C-alkyl product (30—33). Grignard reagents require two moles of dimethyl sulfate for complete reaction. 

Later it was synthesized in a batch process from dimethyl ether and sulfur thoxide (93) and this combination was adapted for continuous operation. Gaseous dimethyl ether was bubbled at 15.4 kg/h into the bottom of a tower 20 cm in diameter and 365 cm high and filled with the reaction product dimethyl sulfate. Liquid sulfur thoxide was introduced at 26.5 kg/h at the top of the tower. The mildly exothermic reaction was controlled at 45—47°C, and the reaction product (96—97 wt % dimethyl sulfate, sulfuhc acid, and methyl hydrogen sulfate) was continuously withdrawn and purified by vacuum distillation over sodium sulfate. The yield was almost quantitative, and the product was a clear, colorless, mobile Hquid. A modified process is deschbed in Reference 94. Properties are Hsted in Table 3. 

Oiganometallic usage is shown in the piepaiation of titanium- oi vanadium-containing catalysts foi the polymerisation of styrene or butadiene by the reaction of dimethyl sulfate with the metal chloride (145). Free-radical activity is proposed for the quaternary product from dimethylaruline and dimethyl sulfate and for the product from l,l,4,4-tetramethyl-2-tetra2ene and dimethyl sulfate (146,147). 

Trimethyl isocyanurate [827-16-7] can be synthesized in 60% yield by the reaction of CA with dimethyl sulfate in alkaline medium (13) or with diazomethane (63) and in essentially quantitative yield by thermal rearrangement of trimethyl cyanurate [877-89-4]. Isomerization of alkyl cyanurates to the corresponding isocyanurates is frequendy observed (11,64). 

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