Preparation And Properties Of Betaine Cyclodextrin Inclusion Complex

Cyclodextrins and their derivatives have extensive use in chemical analysis, drug controlled realease and grocery production, because of the good performance of inclusion as host with good corrosion inhibition and transport capacity. This paper focuses on the basis of cyclodextrin supramolecular retarded acid, which was used as a new type of sandstone acidizing acidification system. The supramolecular retarded acid has dual retarded properties due to the recognition performance, it needs one more step than conventional retarded acid.To improve oilfield production efficiently and intelligently, the purpose of this paper reports the application of cyclodextrin derivatives on the performance of inclusion and acidification process.In this paper, CM-P-CD was prepared using β-CD and chloroacetic acid through Williamson reaction, then the a-halogenated reaction was conducted on CM-β-CD to form cyclodextrin derivatives with halogenated base. Then the trimethylamine was introduced to cyclodextrin derivatives with halogenated base and prepare the betaine cyclodextrins. The betaine cyclodextrin was used as the host body to include organic phosphonic acid. Structures characterization and analyzes of cyclodextrin derivatives were confirmed by infrared spectrum (IR), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results proved the successful preparation of betaine cyclodextrins and the formation of inclusion compound.This paper studied the characteristics and mechanism of supramolecular retarded acid system. With the increasing of the temperature, the clathrate will release the organic phosphonic acid to trigger acidification. In addition, organic phosphonic acid is a kind of multi-hydrogen acid, as its gradual ionization in fluoride salt reaction generates hydrofluoric acid and played a dual acidification effect to achieve the deep acidizing sandstone reservoir. By simulating the formation of core displacement experiment, it could be found that at the beginning of the acidification, the supramolecular retarded acid acidification rate is low, so it can avoid conventional acidification of HF in the reservoir by a large amount of consumption. And in the second stage of core displacement experiment, the permeability of sand filling tube had obvious promotion after the supermolecular retarded acid acidification, which can prove that supramolecular retarded acid has a good slow effect and can prevent the secondary precipitation.The results of molecule recognize tests showed that oil molecules can interact with betaine-cyclodextrin-HEDP and drive the guest of betaine-cyclodextrin-HEDP out of the cavity to react with ammonium bifluoride.