Abstract: A gadolinium chelate, a preparation method therefor, and an application thereof. The gadolinium chelate is a complex formed by chelation of gadolinium ions and macromolecules. The macromolecules comprise any one of or a copolymer or mixture of two or more of carboxylic acid-containing high-molecular polymers, amino-containing high-molecular polymers, hydroxyl-containing high-molecular polymers, polyester high-molecular polymers, polyether high-molecular polymers, polyamide high-molecular polymers, proteins, polypeptides, and polysaccharides. The gadolinium ions and the macromolecules form the gadolinium chelate by means of chelation. The gadolinium chelate is a water-soluble macromolecular drug, can improve a longitudinal relaxation rate r1 and reduce a ratio of r2/r1, has good water-solubility and high stability, and meanwhile, can exhibit a good imaging effect in a short period of time and shorten an MRI time.

Abstract: The present invention provides a method for producing of ultra-clean and high-purity N-methyl pyrrolidone through using industrial grade N-methyl pyrrolidone as raw material. After the pretreatment, sorption and dehydration with 4A molecular sieve, twice membrane filtrations are carried out through using ?-cyclodextrin composite membrane for the first and 18-crown-6 composite membrane for the second. The filtrate is rectified under vacuum and filtered through using complexant composite microporous membrane to obtain the product. The ultra-clean and high-purity N-methyl pyrrolidone, produced by the method provided by the present invention, is up to the SEMI C8 standard. And the purity of the product is over 99.8%, the moisture content is less than 0.03%, and the content of single metal ion is less than 1 ppb. Comparing to the prior art, the present invention has the advantage such as the stable quality of the product, simple operation, and is suitable for industrial continuous production.

Abstract: The present invention provides a method for producing of ultra-clean and high-purity N-methyl pyrrolidone through using industrial grade N-methyl pyrrolidone as raw material. After the pretreatment, sorption and dehydration with 4A molecular sieve, twice membrane filtrations are carried out through using ?-cyclodextrin composite membrane for the first and 18-crown-6 composite membrane for the second. The filtrate is rectified under vacuum and filtered through using complexant composite microporous membrane to obtain the product. The ultra-clean and high-purity N-methyl pyrrolidone, produced by the method provided by the present invention, is up to the SEMI C8 standard. And the purity of the product is over 99.8%, the moisture content is less than 0.03%, and the content of single metal ion is less than 1 ppb. Comparing to the prior art, the present invention has the advantage such as the stable quality of the product, simple operation, and is suitable for industrial continuous production.