Acid anhydrides amines

Photocationic initiators. Epoxy resins can be cross-linked by compounds containing active hydrogen, e.g., carboxylic acids, anhydrides, amines, phenols etc., or by the ionic polymerization process. Lewis acids such as BF3 and usually a crystalline complex of BF3 with amines, e.g., BF3 NH2C2H5, can be used for curing reaction at 80-100° C [124]. 

Functionalized PPE may he prepared hy allowing PPE to react with a species that contains both a C=C bond and a reactive moiety, such as hydroxyl, acid, anhydride, amine, imide, epoxy, etc. Examples of species of the acid and anhydride type include maleic anhydride, fumaric acid, and citraconic anhydride. ... 

Curing agent Up to 60 Polymerization Acid anhydrides, amines, phenols... 

It will also reduce acid chlorides, acid anhydrides and aldehydes to primary alcohols, ketones to secondary alcohols, and amides to the corresponding amines R-CONHi -> R CHiNH. Nitro-hydrocarbons if aromatic are... 

Almost insoluble in cold water. Higher alcohols (including benzyl alcohol), higher phenols (e.g., naphthols), metaformaldehyde, paraldehyde, aromatic aldehydes, higher ketones (including acetophenone), aromatic acids, most esters, ethers, oxamide and domatic amides, sulphonamides, aromatic imides, aromatic nitriles, aromatic acid anhydrides, aromatic acid chlorides, sulphonyl chlorides, starch, aromatic amines, anilides, tyrosine, cystine, nitrocompounds, uric acid, halogeno-hydrocarbons, hydrocarbons. 

Amides are readily prepared by acylation of ammonia and amines with acyl chlorides acid anhydrides or esters... 

Two molar equivalents of amine are required m the reaction with acyl chlorides and acid anhydrides one molecule of amine acts as a nucleophile the second as a Brpnsted base... 

Nucleophilic acyl substitution (Sections 20 4 20 6 and 20 12) Acylation of am monia and amines by an acyl chloride acid anhydride or ester is an excep tionally effective method for the for mation of carbon-nitrogen bonds... 

Amines are convert ed to amides on reaction with acyl chlorides Other acylating agents such as carboxylic acid anhydrides and esters may also be used but are less reactive... 

Step 2 Structurally O acylisoureas resemble carboxylic acid anhydrides and are powerful acylatmg agents In the reaction s second stage the amine adds to the carbonyl group of the O acylisourea to give a tetrahedral intermediate... 

The Perkin reaction, uti1i2ing an aromatic aldehyde, an acid anhydride, and a base such as an acid salt or amine, produces the corresponding a,P-unsaturated acid. 

Trifluoromethanesulfonic acid anhydride, bp 84°C, is prepared by refluxing the acid over an excess of phosphorous pentoxide (18,26). The anhydride reacts instantaneously with ammonia or amines to form trifluoromethanesulfonamides. The anhydride reacts with most polar organic solvents. 

The resulting bisepoxy compounds are cross-linked cold with polyamines, if necessary with added accelerators. A hot cure can either be accomphshed with amines or anhydrides (eg, phthaUc acid anhydride). If suitable initiators are present, EP systems can also be cross-linked by radiation. 

Chemical Properties The formation of salts with acids is the most characteristic reaction of amines. Since the amines are soluble in organic solvents and the salts are usually not soluble, acidic products can be conveniendy separated by the reaction with an amine, the unshared electron pair on the amine nitrogen acting as proton acceptor. Amines are good nucleophiles reactions of amines at the nitrogen atom have as a first step the formation of a bond with the unshared electron pair of nitrogen, eg, reactions with acid anhydrides, haUdes, and esters, with carbon dioxide or carbon disulfide, and with isocyanic or isothiocyanic acid derivatives. 

Both amines and acid anhydrides are extensively used cross-linking agents. The resins may also be modified by reacting with other polymers containing hydroxyl or mercaptan groupings, e.g. 

Compared with standard diglycidyl ether resins, the liquid cyclic aliphatic resins are paler in colour and have a much lower viscosity. Whereas in general the cyclic aliphatic resins react more slowly with amines, there is less difference with acid anhydrides. Table 26.7 provides data illustrating this point. 

The epoxidised polybutadiene resins available to date are more viscous than the diglycidyl ethers except where volatile diluents are employed. They are less reactive with amines but have a similar reactivity with acid anhydride hardeners. Cured resins have heat distortion temperatures substantially higher than the conventional amine-cured diglycidyl ether resins. A casting made from an epoxidised polybutadiene hardened with maleic anhydride and cured for two hours at 50°C plus three hours at 155°C plus 24 hours at 200°C gave a heat... 

As with the other non-glycidyl ether resins the absence of the ether oxygen near to the epoxide group results in low reactivity with amine hardemers whereas activity with acid anhydride proceeds at reasonable rates. 

Acid anhydride and amine hardening agents, Adhesives, plastics, moulding resins and... 

Epichlorohydrin with bisphenol A. The curing agents may pose significant health hazards, e.g. amines (triethylamine, p-phenylenediamine, diethylenetriamine) or acid anhydrides (pyromellitic dianhydride)... 

Group of plastics composed of resins produced by reactions of epoxides or oxiranes with compounds such as amines, phenols, alcohols, carboxylic acids, acid anhydrides and unsaturated compounds. 

Lithium aluminum hydride (LiAlH4) is the most powerful of the hydride reagents. It reduces acid chlorides, esters, lactones, acids, anhydrides, aldehydes, ketones and epoxides to alcohols amides, nitriles, imines and oximes to amines primary and secondary alkyl halides and toluenesulfonates to... 

Reaction with ammonia and amines (Section 20.14) Acid anhydrides react with ammonia and amines to form amides. 

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