Acid anhydride reaction summary

In summary, reactions of nitronates with acid anhydrides or acyl chlorides give the O-acylated products, and reactions with acyl imidazoles, phenyl esters, acyl nitriles, and enol-lactones gives the C-acylated products, (see Eq. 5.13).25 The C/O selectivity of nitronate acylation by RCOX is qualitatively correlated with strength (pKJ of the acid HX conjugated to the leaving group X .25... 

The most important reactions of carboxylic acids are the conversions to various carboxylic acid derivatives, e.g. acid chlorides, acid anhydrides and esters. Esters are prepared by the reaction of carboxylic acids and alcohols. The reaction is acid catalysed and is known as Fischer esterification (see Section 5.5.5). Acid chlorides are obtained from carboxylic acids by the treatment of thionyl chloride (SOCI2) or oxalyl chloride [(COCl)2], and acid anhydrides are produced from two carboxylic acids. A summary of the conversion of carboxylic acid is presented here. All these conversions involve nucleophilic acyl substitutions (see Section 5.5.5). 

In Chapter 2 the DSC technique is discussed in terms of instruments, experimental methods, and ways of analysing the kinetic data. Chapter 3 provides a brief summary of epoxy resin curing reactions. Results of studies on the application of DSC to the cure of epoxy resins are reviewed and discussed in Chapter 4. These results are concerned with the use of carboxylic acid anhydrides, primary and secondary amines, dicyanodiamide, and imidazoles as curing agents. 

In Summary The problems of Friedel-Crafts alkylation (multiple substitution and carboca-tion rearrangements) are avoided in Friedel-Crafts acylations, in which an acyl halide or carboxylic acid anhydride is the reaction partner, in the presence of a Lewis acid. The intermediate acylium cations undergo electrophilic aromatic substitution to yield the corresponding aromatic ketones. 

In summary, therefore, the detailed mechanism of the hydrolysis of carboxylic anhydrides is still in doubt and we must hope for further experimental evidence to clarify the position. As for the hydrolysis of the other carboxylic acid derivatives dealt with in this chapter, none of the mechanistic criteria, that have been used to interpret the kinetic data, gives an unambiguous interpretation, resulting in a situation where details of mechanism are open to argument. This is particularly the case for solvolysis reactions where uncertainty as to the structure and effect of the solvent preclude a firm assignment of transition state structures. This is not to say that the mechanisms are not... 

Summary beta-HMX can be prepared by reacting hexamine with ammonium nitrate and nitric acid in the presence of excess glacial acetic acid and acetic anhydride. The rate of additions is crucial to ensure proper HMX formation. After the reaction is complete, the alpha-HMX is refluxed with water to ensure quality and purification. The resulting water insoluble product is then filtered-off, and then recrystallized from acetone to produce excellent crystals of beta-HMX. Commercial Industrial note For related, or similar information, see Serial No. 696,888, November 15th, 1957, by The United States Army, to Jean P. Picard, Morristown, NJ. Part or parts of this laboratory process may be protected by international, and/or commercial/industrial processes. Before using this process to legally manufacture the mentioned explosive, with intent to sell, consult any protected commercial or industrial processes related to, similar to, or additional to, the process discussed in this procedure. This process may be used to legally prepare the mentioned explosive for laboratory, educational, or research purposes. 

Summary PVN is conveniently prepared by reacting polyvinyl alcohol (PVA) with 99% nitric acid in the presence of acetic anhydride in methylene chloride. The reaction is mild, and is kept at a temperature below 0 Celsius at all times to avoid decomposition of the polyvinyl alcohol. After the initial reaction, the reaction mixture is refluxed for a short period of time, and then evaporated to remove the solvent. Thereafter, the PVN product is collected by drowning the reaming reaction mixture into ice-cold water, followed by filtration, washing, and then drying. 

Summary Tetracene is readily prepared by the diazoniurn reaction involving sodium nitrite. To carryout this reaction, ami noguanidine hydrochloride istreated with glacial acetic acid in the presence of acetic anhydride, and the resulting mixture... 

Aldehyde dlacetates. 1,1-Dlacetates of aldehydes can be prepared by using soluble protlc acids. With a catalytic amount of NATION, the same dlacetates can be obtained by vigorously stirring equivalent amounts of the aldehyde and freshly distilled acetic anhydride (25). The general reaction In equation 10 is exemplified by the summary In Table VIII. The yields are good with aromatic aldehydes and alkanals. 

Summary of Reaction of Acid Chlorides, Anhydrides, Esters, and Amides with Water... 

Kienle and Petke were among the first to study the effect on the ratio and properties of alkyd resin formation of acids other than phthalic acid or anhydride. In all cases where either aliphatic or aromatic acids were used the greatest time involved the first half of the reaction. The acid values near gelation were between the calculated values for the dimer and tetramer. The percent esterification attained at gelation was about the same for the different dibasic acids (approximately the same amount of water evolved). A summary of some other acids in comparison to phthalic anhydride is shown in Table V. 

The interpolymers from natural rubber plus monomer vary widely methyl methacrylate and styrene give a soluble product whereas chloroprene, acrylonitrile and methacrylic acid produce a gel containing the polymerized monomer. Extensive investigations were carried out on maleic anhydride [15, 99-101] for the reinforcement of rubber and because of the peculiar reaction. Table 5.15 is a summary of the most important results obtained using natural and synthetic rubbers with different monomers. 

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