Magnesium perchlorate, as catalyst

Magnesium perchlorate, as catalyst in acetylation of starch, I, 289 Maleic acid,.dihydroxy-, II, 96 III, 149 Malic acid, III, 238, 241 IV, 85 labelled with isotopic C, III, 140, 249 Malonic acid, II, 155 III, 238 protection of enzyme by, V, 54 Maltamylase. See under Amylases. Maltase, IV, 25, 30. See also a-Glucosi-dase. 

Magnesium perchlorate as catalyst Ketones from carboxylic acid anhydrides... 

Production of cellulose esters from aromatic acids has not been commercialized because of unfavorable economics. These esters are usually prepared from highly reactive regenerated cellulose, and their physical properties do not differ markedly from cellulose esters prepared from the more readily available aHphatic acids. Benzoate esters have been prepared from regenerated cellulose with benzoyl chloride in pyridine—nitrobenzene (27) or benzene (28). These benzoate esters are soluble in common organic solvents such as acetone or chloroform. Benzoate esters, as well as the nitrochloro-, and methoxy-substituted benzoates, have been prepared from cellulose with the appropriate aromatic acid and chloroacetic anhydride as the impelling agent and magnesium perchlorate as the catalyst (29). 

Elsewhere, Faita et al. (438) bound the Evans chiral auxiliary to Wang or Merrifield resin for use as a dipolarophile in cycloadditions with C,N-diphenyl-nitrone. Yields on both resins are significantly reduced in comparison to the solution phase reaction (43-20% compared to 95%) but are unaffected by addition of magnesium perchlorate or scandium triflate catalyst. A one-pot process has been reported by Hinzen and Ley (439) that oxidizes secondary hydroxylamines to the... 

Since aluminum chloride often induces polymerization, it is generally replaced by other milder catalysts, such as tin tetrachloride,128-131 zinc chloride,131, 132 magnesium perchlorate,133 ferric... 

Magnesium perchlorate has been used as a catalyst for the synthesis of benzothiazepines 153 from chalcones and 2-aminothiophenol <07JHC541> while derivatives 154 using 3-cinnamoyl coumarin as the a,p-unsaturated ketone have also been synthesised <07JHC145>. The reaction of 2-aminothiophenol with itaconic anhydride also gives the benzothiazepine system 155 <07JHC457> while dibenzothiazepines 157 were formed by denitrocyclisation of the sulfide 156 <07JHC1247>. 

Sulfuryl chloride and magnesium perchlorate have been suggested as acetylation catalysts for starch. Sulfur dioxide in acetic acid/ sulfur trioxide in acetic anhydride, and sulfonated fatty acid or sulfonated salicylic acid in a mixture of acetic anhydride and acetic acid have also been reported to acetylate starch. 

A polymerisation variant is to use as catalyst oleum (a 30-60% solution of SOs in sulfuric acid), or better, in order to accelerate the reaction, a catalytic mixture of oleum-perchloric acid (or a perchlorate, such as magnesium perchlorate) [12,16,25,28]. Similar structures with sulfate ester units (structure 7.7) are obtained. By the hydrolysis of the resulting structure the desired PTHF with terminal hydroxyl groups is obtained [13, 25, 28]. 

Pyrotechnic mixtures may also contain additional components that are added to modify the bum rate, enhance the pyrotechnic effect, or serve as a binder to maintain the homogeneity of the blended mixture and provide mechanical strength when the composition is pressed or consoHdated into a tube or other container. These additional components may also function as oxidizers or fuels in the composition, and it can be anticipated that the heat output, bum rate, and ignition sensitivity may all be affected by the addition of another component to a pyrotechnic composition. An example of an additional component is the use of a catalyst, such as iron oxide, to enhance the decomposition rate of ammonium perchlorate. Diatomaceous earth or coarse sawdust may be used to slow up the bum rate of a composition, or magnesium carbonate (an acid neutralizer) may be added to help stabilize mixtures that contain an acid-sensitive component such as potassium chlorate. Binders include such materials as dextrin (partially hydrolyzed starch), various gums, and assorted polymers such as poly(vinyl alcohol), epoxies, and polyesters. Polybutadiene mbber binders are widely used as fuels and binders in the soHd propellant industry. The production of colored flames is enhanced by the presence of chlorine atoms in the pyrotechnic flame, so chlorine donors such as poly(vinyl chloride) or chlorinated mbber are often added to color-producing compositions, where they also serve as fuels. 

COPPER CYANIDE (544-92-3) CCuN May be unstable and explosive. Contact with nitric acid causes decomposition, releasing toxic and flammable hydrogen cyanide fumes. Reacts violently with powdered magnesium (incandescence). Reacts, possibly violently, with strong oxidizers, chlorine, fluorine, peroxides metal chlorates, nitrates, nitrites, perchlorates. Can act as a polymerization catalyst keep away from easily polymerized materials. On small fires, use dry chemical powder (such as Purple-K-Powder), foam, or COj extinguishers. Thermal decomposition releases toxic and flammable hydrogen cyanide gas. 

In nonenzymic reductions with synthetic dihydropyridines magnesium ions, usually as the perchlorate, Mg(C104)2, are the best electrophilic catalysts so far found. The Mg ion may in fact do more than just polarize the carbonyl group although this remains a point of contention. Other catalysts have been used but in general with less success than Mg ... 

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