Methanesulfonic acid used catalyst

Preparation by reaction of gallic acid with pyrocatechol in chlorobenzene in the presence of methanesulfonic acid for 6 h between 65° and 75° (90%) or by using boron trifluoride-etherate instead of methanesulfonic acid as catalyst (10%). 

Nearly all commercial acetylations are realized using acid catalysts. Catalytic acetylation of alcohols can be carried out using mineral acids, eg, perchloric acid [7601-90-3], phosphoric acid [7664-38-2], sulfuric acid [7664-93-9], benzenesulfonic acid [98-11-3], or methanesulfonic acid [75-75-2], as the catalyst. Certain acid-reacting ion-exchange resins may also be used, but these tend to decompose in hot acetic acid. Mordenite [12445-20-4], a decationized Y-zeohte, is a useful acetylation catalyst (28) and aluminum chloride [7446-70-0], catalyzes / -butanol [71-36-3] acetylation (29). 

The choice of catalyst is based primarily on economic effects and product purity requirements. More recentiy, the handling of waste associated with the choice of catalyst has become an important factor in the economic evaluation. Catalysts that produce less waste and more easily handled waste by-products are strongly preferred by alkylphenol producers. Some commonly used catalysts are sulfuric acid, boron trifluoride, aluminum phenoxide, methanesulfonic acid, toluene—xylene sulfonic acid, cationic-exchange resin, acidic clays, and modified zeoHtes. 

In laboratory preparations, sulfuric acid and hydrochloric acid have classically been used as esterification catalysts. However, formation of alkyl chlorides or dehydration, isomerization, or polymerization side reactions may result. Sulfonic acids, such as benzenesulfonic acid, toluenesulfonic acid, or methanesulfonic acid, are widely used in plant operations because of their less corrosive nature. Phosphoric acid is sometimes employed, but it leads to rather slow reactions. Soluble or supported metal salts minimize side reactions but usually require higher temperatures than strong acids. 

DCC has also been used. The most common catalyst for aliphatic R is concentrated sulfuric acid. The reaction is an equilibrium and is driven to the right by removal of water or by the use of excess reagents. For aromatic R the best catalyst is methanesulfonic acid, which is also used as the solvent. 

A variety of para-substituted 2-phenyl-2-butanols undergo quick and efficient reductions to the corresponding 2-phenylbutanes when they are dissolved in dichloromethane and a 2-10% excess of phenylmethylneopentylsilane and boron trifluoride is introduced at 0° (Eq. 30).126 Several reactions deserve mention. For example, when R = CF3, use of trifluoroacetic acid produces no hydrocarbon product, even after two hours of reaction time. In contrast, addition of boron trifluoride catalyst provides an 80% yield of product after only two minutes. When R = MeO, both trifluoroacetic acid and boron trifluoride produce a quantitative yield of the hydrocarbon within two minutes. However, when R = NO2, attempts to promote the reduction with either trifluoroacetic acid or even methanesulfonic acid fail even after reaction periods of up to eight hours, only recovered starting alcohol is obtained. Use of boron trifluoride provides a quantitative conversion into 2-(/ -nitrophenyl)butane after only ten minutes. It is significant that the normally easily reducible nitro group survives these conditions entirely intact.126129 Triethylsilane may be used as the silane.143... 

This reaction has been studied in mote detail, and a study of the cyclization of thiobenzamide using DMSO as oxidant led to the following conclusions. There must be an oxygen donor oxidant present and it is essential to use a solvent of high polarity such as dimethyl formanide (DMF). An acid catalyst is essential and the counterion is also important HCl and HBr are good catalysts but sulfuric acid, methanesulfonic acid, and trifluoroacetic acid do not give... 

Gibson and co-workers reacted tertiary alcohol diamides with SOCI2 to prepare a series of bis(oxazoline) ligands 20a-f that are used as catalysts for asymmetric cyclopropanations. This method was preferred for preparation of 20e-f. Use of a strong acid such as methanesulfonic acid promoted extensive elimination of water to give the corresponding enamides (Scheme 8.9). 

In a subsequent study of oxygen heterocychzation, Andersson et al. investigated various catalyst reoxidation conditions with the Pd(OAc)2/DMSO catalyst system (Eq. 27, Table 3) [ 150]. Several conditions result in high substrate conversion to the product, including the use of BQ, BQ with methanesulfonic acid, and molecular oxygen, with and without copper(II) salts as a cooxidant. Only the aerobic methods enable formation of the product 37 with high regio-selectivity. The presence of a copper cocatalyst enhances the rate but is not necessary for catalysis. 

From this perspective, Teles used [AuMePPh3] as a catalyst and methanesulfonic acid as a co-catalyst when adding alcohols to alkynes, and achieved excellent results [14]. The scope of this reaction covered both internal and terminal alkynes. In the case of symmetrical alkynes, the only product formed in the presence of excess alcohol came from dialkoxylation. 

Hull and Conant in 1927 showed that weak organic bases (ketones and aldehydes) will form salts with perchloric acid in nonaqueous solvents. This results from the ability of perchlonc aad in nonaqueous systems to protonate these weak bases. These early investigators called such a system a superacid. Some authorities believe that any protic acid that is stronger than sulfunc aad (100%) should be typed as a superaad. Based upon this criterion, fluorosulfuric arid and trifluoro-methanesulfonic acid, among others, are so classified. Acidic oxides (silica and silica-aluminai have been used as solid acid catalysts for many years. Within the last few years, solid acid systems of considerably greater strength have been developed and can he classified as solid superacids. 

Recovery of naturally occurring esters is accomplished by steam distillation, extraction, pressing, or by a combination of these processes. Synthetic esters are generally prepared by reaction of an alcohol with an organic acid in the presence of a catalyst such as sulfuric acid,y>-toluenesulfonic acid, or methanesulfonic acid. Ion-exchange resins of the sulfonic acid type can also be used, and an azeotroping agent such as benzene, toluene, or cyclohexane... 

Wang et al. [25] used trimethylsilylmethanesulfonate (TMSOMs) prepared from methanesulfonic acid and allyltrimethylsilane, as the catalyst. This catalyst is cheaper and easier to handle than TMSOTf and gives similar yields of condensation products (Scheme 13.24). 

Several examples have been described on Lewis acid and base catalyzed Michael additions. Cyclopentanone-2-carboxylic acid ethylester was added at room temperature to methyl vinyl ketone using 2 mol% FeCl3 -6 H20 as catalyst yielding > 90% of the addition product (Scheme 11) [31]. Cerium(III) chloride in the presence of sodium iodide [32] and trifluoro-methanesulfonic acid have been used as catalysts as well [33]. 

Beginning with 9-fluorene carboxylic acid, high molecular weight poly(9-hydroxy methyl-9-fluorene carboxylic acid) has been prepared by the homopolymerization of 9-hydroxymethyl-9-fluorene carboxylic acid using trifluoro methanesulfonate as the catalyst. This polymeric agent readily formed donor-acceptor complexes with 1,3-dinitrobenzene and is suitable as a charge transport material. 

Putnam reported that allylamines may also be used as ammonia equivalents in the Pd-catalyzed coupHng reaction [114]. The desired C-N formation was effected with the DPPF/Pd-catalyst subsequent cleavage of the allyl group was achieved by treatment with methanesulfonic acid in the presence of a Pd/C catalyst, Eq. (134). 

Preferably the reaction in accordance with the invention is performed in the presence of a suitable catalyst, proton acids such as for instance haloid acids, sulfuric acid, phosphoric acid, perchloric acid, organic sulfonic acids, such as for instance methanesulfonic acid and p-toluenesulfonic acid, carboxylic acids, such as for instance oxalic acid, trifluoroacetic acid and other Lewis acids, such for instance boron trifluoride, ferric chloride, zinc chloride, zinc bromide, stannic chloride, titanium chloride or iodine having proved to be suitable. Furthermore mixtures of the individual catalysts may be used in certain cases. 

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