Methanedisulfonic acid

The polyformals which were obtained in this manner from the alicyclic diols were highly colored, and their inherent viscosities were below 0.4 (determined using 60/40 phenol-tetrachloroethane mixture as solvent). Catalysts which were used were ferric chloride, methanedisulfonic acid, camphorsulfonic acid, antimony trifluoride, and titanium tetrafluoride. Polymers were not obtained with the latter two. 

Paraformaldehyde Method. 2,2,4,4-Tetramethyl-1,3-cyclobutanediol. A 2-liter, three-necked flask was fitted with a glass stirrer, thermometer, and Dean-Stark trap which was filled with distilled cyclohexane and attached to a water-cooled condenser. In the flask were placed 216 grams (1.5 moles) of 2,2,4,4-tetramethyl-l,3-cyclobutanediol (1 to 1 cis-/trans- mixture), 52.2 grams (1.65 moles, if 95% pure) of paraformaldehyde, 1200 ml. of distilled cyclohexane, and 0.20 gram of methanedisulfonic acid in a 10 to 25% aqueous solution. (The catalyst solution had been treated with Darco G-60 to remove all color.) While this mixture was stirred at 60° C., the paraformaldehyde depolymerized to formaldehyde, which reacted with the diol. Complete reaction of these two components was indicated when they had gone into solution. This required about 1 hour. 

Effective catalysts for preparing the polyformals were p-toluenesulfonic acid, camphorsulfonic acid, methanedisulfonic acid, and perchloric acid. Various other acidic compounds were evaluated as catalysts with tetramethylcyclobutanediol. In these experiments, 0.5 to 1.0 gram of acidic compound per mole of tetramethylcyclobutanediol was normally added. If insufficient water was obtained, more catalyst was added. If the prepolymer was obtained but an appreciable amount of brown color was present, less catalyst was then used. Compounds which did not catalyze the reaction (no water obtained) were phosphoric acid, zinc chloride, trifluoroacetic acid, and heptafluorobutyric acid. Incomplete reactions (insufficient water) took place with concentrated hydrochloric acid, concentrated nitric acid, zinc fluoroborate, or Amberlite IRC-50 ion exchange resin as catalyst. A prepolymer was obtained when boron trifluoride etherate was used, but buildup did not take place in the solid phase (catalyst probably too volatile). Brown or speckled-brown polymers (after solid-phase buildup) were obtained with catalysts containing sulfonic acid groups (benzenesulfonic, dodecylbenzenesulfonic, sulfo-acetic, methanetrisulfonic, sulfuric, p-toluenesulfonic, camphorsulfonic, and methanedisulfonic acids). To obtain white polymers from tetramethylcyclobutanediol it was necessary to treat the solvent and prepolymer reaction mixture as previously described. (White polyformals were obtained from the other diols without this treatment.)... 

In these experiments with tetramethylcyclobutanediol, it was found that methanedisulfonic acid gave higher polyformals than the other catalysts. Inherent viscosities up to 1.7 were obtained, whereas values of only 0.8 to 0.9 resulted with camphorsulfonic acid or p-toluenesulfonic acid and 0.7 when perchloric acid was used. It was necessary to use 0.002 to 0.005 equivalent of camphorsulfonic acid or toluenesulfonic acid per mole of diol in order to obtain the poly formal, but 0.001 equivalent of perchloric acid or 0.001 to 0.002 equivalent (0.0005 to 0.001 mole) of methanedisulfonic acid was sufficient to catalyze the polymerization in the various solvents. When appreciably less catalyst was used, the polymers did not build up, and when appreciably more was used, brown polymers were obtained. 

Titration indicated that almost all of the methanedisulfonic acid catalyst (or its reaction products) was present in the black material which was deposited on the flask walls during the latter stages of the tetramethylcyclobutanediol prepolymer preparation when hexane was the solvent. Since the catalyst is very soluble in water and insoluble in hydrocarbons, it evidently came out of solution with some decomposition products when no water remained in the system. An analysis of the prepolymer indicated that only 0.002% sulfur (1% of the original catalyst) was present. After solid-phase buildup, less than 0.001% sulfur was found in the polymer. 

Aluminum-magnesium-sodium silicate. See Sodium magnesium aluminosilicate Aluminum metal. SeeAluminum Aluminum methionate CAS 52667-15-9 EINECS/ELINCS 258-085-7 Synonyms Methanedisulfonic acid, aluminum salt (3 2)... 

Methanedisulfonic acid Methionic acid CH4OBS2 503-40-2 176.169 98 IH,0 sHN03... 

Alkanedisulfonic acids are prepared by heating an alkanesulfonic acid with chlorosulfonic acid at 70-160 °C in the presence of air (oxygen), optionally over an activated charcoal catalyst. Methanesulfonic acid reacted with chlorosulfonic acid at 100 °C (1 hour) to give a mixture containing methanedisulfonic acid (34%). (For further details see Chapter 9 p 267.)... 

When acetyl chloride 102 was heated with more chlorosulfonic acid above 60 °C, the intermediate acetyl chlorosulfonate 103 was converted into chlorosulfo-nylmethanesulfonic acid 106, which by hydrolysis afforded methanedisulfonic acid 107. Ether extraction of the reaction mixture also gave a small amount (ca. 3%) of a condensation product suggested to be 2-methylpyran-4-one-6-acetic acid 108 (Scheme 8). ... 

The latter reaction gave a substantially increased jdeld of methanedisulfonyl chloride (39, 61%), although chlorosulfonic acid under these conditions did not yield pure methanedisulfonyl chloride 39, which was instead obtained by warming methanedisulfonic acid 36 with phosphorus pentachloride. However, it is possible that the disulfonyl chloride 39 could have been prepared as the sole product by... 

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