cyclic anhydride

cyclic anhydride

[′sīk·lik an′hī‚drīd]
(organic chemistry)
A ring compound formed by the removal of water from a compound; an example is phthalic anhydride.
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In this reaction we were able to form both substituted and unsubstituted cyclic imides through two condensation reactions of the cyclic anhydride and the glutamic acid moieties, respectively.
The cyclic anhydride reacts with cellulose to form an ester and regenerate one carboxylic acid group (2 10 11).
Generally, hyperbranched polyesteramides (HBPAs) were synthesized by the bulk polycondensation of a trifunctional dialkanolamine (DAA) as bB2 monomer, where b and B2 represent the secondary amine and the two alcohol functional groups, respectively, and a difunctional cyclic anhydride (CAn), as an Aa monomer, where Aa represents the anhydride functional group [31].
Cyclic anhydride and protonated amide functional groups were identified as reaction intermediates, which resulted in carboxylic ester linkages between MSO and cellulose upon elevated temperature curing.
Figure 1 illustrates the reaction of cyclic anhydride (after grafting maleic anhydride is converted into succinic anhydride) with end amino or hydroxyl groups of fiber polymers.
Compared with the spectrum of the pure PP, a new absorption band at 1725 [cm.sup.-1] which is attributed to the absorption of the acid-type carbonyl groups is observed in all the grafted samples, but absorption bands at 1785 and 1850 [cm.sup.-1] which are assigned to the absorption of the carbonyl group of cyclic anhydride do not appear.
(2.) Cavitt, TB, Photoinitiation of Free-Radical Polymerization by Aryl Disulfide, Cyclic Anhydride, and Phthalimide Derrivatives: ProQuest Information and Learning Company, Ann Arbor, MI (2002)
It contains a compound comprising hydroxylamide groups characterized in that at first a compound comprising hydroxyalkyl amide units and carboxylic acid units is obtained by reacting a cyclic anhydride and an alkanolamine in a mixing device and that secondly the binder composition is obtained by mixing the compound and a polymer in a second mixing device.
Compared FTIR spectrum of DP-g-MAH to that of DP, new the absorbing peaks at 1861 [cm.sup.-1] and 1789 [cm.sup.-1], which correspond to asymmetric C=O stretching and symmetric C=O stretching in the cyclic anhydride (33), respectively, mean that MAH molecules have been grafted successfully onto DP macromolecular chains.
Compared with styrene homopolymer with [T.sub.g] of 102[degrees]C, the alternating copolymer possesses higher [T.sub.g] ranging from 148 to 153[degrees]C because it is of more rigid structure, originating from cyclic anhydride in the main chains of the alternating copolymer.
1), the absorption peaks at 1775, 1785, 1840, and 1860 [cm.sub.-1] (which are characteristic absorptions for cyclic anhydride groups) have been found, which indicate the presence of MA units in the iPP-g-MA copolymer.
The films were then dried in a vacuum oven at 55[degrees]C for 12 hrs to allow complete cyclization of any diacid into the cyclic anhydride form.

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