CN-122006683-A - Mixed mode chromatographic stationary phase based on cyclic polyamine and preparation method thereof

CN122006683ACN 122006683 ACN122006683 ACN 122006683ACN-122006683-A

Abstract

The invention discloses a mixed mode chromatographic stationary phase based on cyclic polyamine and a preparation method thereof, N-monoalkylated piperazine is firstly obtained by a selective N-alkylation technology, then converting the mixture into silane, and fixing the silane on silica gel to prepare the novel mixed mode chromatographic stationary phase based on cyclic polyamine. The selective N-alkylation adopted by the invention has reaction specificity, the silane synthesis is diversified, the obtained stationary phase has obvious alkalinity, excellent hydrophilicity and stability, and is suitable for analyzing high-activity electrophilic reagents, the tendency of the silicon ether bond between the bonding phase and the silica gel matrix to be destroyed by the proton solvent in the mobile phase is weakened, the loss of the chromatographic stationary phase is reduced, and the chromatographic retention capacity is improved.

Inventors

ZHANG MINGLIANG
HAN HAIFENG
CHEN MIN
Zuo Xukang
ZHU MENGXIANG

Assignees

江苏汉德科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260211

Claims (10)

1. A cyclic polyamine-based mixed mode chromatographic stationary phase characterized in that the cyclic polyamine-based mixed mode chromatographic stationary phase has the structure: In the structural formula, X 1 and X 2 are hydroxyl or methyl, R 1 is a bridging group with the number of carbon atoms not less than 3, and R 2 is aliphatic hydrocarbon group with the number of carbon atoms not less than 8.
2. A method of preparing the cyclic polyamine-based mixed mode chromatographic stationary phase of claim 1, comprising the steps of: A. Dissolving halogenated alkane and piperazine in aprotic polar solvent, adding alkali metal carbonate as acid coating agent, stirring under nitrogen protection, heating to 30-70 ℃, reacting 5-10 h, vacuum distilling to remove solvent to obtain solid-liquid mixture, adding extraction solvent to dissolve organic part, adding water to extract and remove excessive piperazine, acid coating agent and by-product alkali metal salt, drying organic phase with saturated sodium chloride solution, vacuum distilling to remove extraction solvent, and crystallizing with solvent with carbon number not more than 4 to obtain N-monoalkylated piperazine; B. Dissolving the N-monoalkylated piperazine obtained in the step A in a dry organic solvent, adding a silane derivative reagent capable of reacting with a secondary amine group into a reaction system, controlling the reaction temperature according to the activity of a reaction substrate, stirring and reacting for 2-10 h, removing the reaction solvent, and crystallizing by using a solvent with carbon number not more than 4 to obtain N-monoalkyl piperazine functionalized silane; C. And C, dissolving the N-monoalkyl piperazine functionalized silane prepared in the step B into a solvent, adding silica gel, heating to 100-120 ℃ under the protection of nitrogen, reacting for 20-30 h, filtering to remove the solvent, washing the filler with aromatic hydrocarbon, ethanol, methanol and acetone in sequence, and drying to obtain the bonded silica gel chromatographic stationary phase.
3. The method of claim 2, wherein in step A, the molar ratio of piperazine to halogenated alkane to acid coating agent is 1.20:1.25-1.01:0.98-1.50:1.55.
4. The method of claim 2, wherein the aprotic polar solvent in step A is N, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone or acetonitrile.
5. The process according to claim 2, wherein in step A, the halogenated hydrocarbon is an alpha-halogenated alkane, the halogen atom is chlorine, bromine or iodine, and the alkane is a C8-C30 normal saturated alkane.
6. The method of claim 2, wherein in step A, the alkali metal carbonate is lithium carbonate, sodium carbonate, potassium carbonate, or cesium carbonate.
7. The process according to claim 2, wherein in step A, the extraction solvent is toluene, ethyl acetate, or 4-methyltetrahydrofuran.
8. The method of claim 2, wherein in step B, the molar ratio of the silane derivatizing agent to the N-monoalkylated piperazine is 0.95:1.25 to 1.01:0.99.
9. The method of claim 2, wherein in step B, the silane derivatizing agent has a structure corresponding to the general formula: Wherein n is a natural number not less than 1, at least one of X 1 、X 2 and X 3 is an alkoxy group, X 4 is an isocyanate, succinic anhydride, bromine, iodine, glycidoxy group, when the target product has only one tertiary amine group, the silane derivatizing agent is a silane having an isocyanate group or succinic anhydride group, and when the target product has two tertiary amine groups, the silane derivatizing agent is a silane having a bromine or iodine or glycidoxy group.
10. The method of claim 2, wherein in step C, the solvent is toluene, xylene, trimethylbenzene, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, or dimethylsulfoxide.

Description

Mixed mode chromatographic stationary phase based on cyclic polyamine and preparation method thereof Technical Field The invention belongs to the technical field of high performance liquid chromatography packing materials, and particularly relates to a mixed mode chromatography stationary phase based on cyclic polyamine and a preparation method thereof. Background In the field of liquid chromatography, alkyl-bonded silica gels, such as octadecyl (C18) and octyl (C8) bonded silica gels, are currently the most widely used packing materials in reverse phase chromatography due to their excellent chemical inertness, stability and mature preparation process, and such packing materials are excellent in separation of nonpolar compounds. However, such fillers do not provide effective retention in the reverse phase mode of high organic ratios when the analyte polarity is enhanced, or hydrophilic, thus there is a need to reduce the organic phase ratio of the mobile phase, i.e., increase the water ratio, but the mobile phase with very high water content does not provide effective retention for strongly polar compounds, such as some purines and saponins. In general, alkyl-bonded stationary phases cannot work stably in pure water, especially pure water containing buffer salts, because they cannot be infiltrated by such liquids. This necessitates the development of chromatographic packing materials that are sufficiently wettable by water. On the other hand, for alkaline analytes with dissociable groups, such as tricyclic antidepressants, quinine, quinidine and other alkaloids, which frequently occur, conventional alkyl fillers often cannot show good separation effects due to the negative hydrogen bonding of residual silicon hydroxyl groups, particularly in analytes with peaks with poor peak-to-peak shapes, severe tailing, and even with excessive retention of peaks. To address the two problems described above, chromatograph workers have successively introduced a variety of new packing materials. The co-bonding of silanes with primary amine groups to silica gel is the earliest solution, this filler has a mixed stationary phase, then primary amine groups are reactive towards certain carbonyl compounds, such as aldehydes and ketones, the lifetime of the filler is compromised, then fillers with polar groups in the bonding phase appear, when the introduced groups are permanently charged (quaternary ammonium groups) or can be charged (secondary or tertiary amines), the fillers with embedded polar groups have both inverting and anion exchange characteristics, can be fully infiltrated by pure water mobile phases, and the undesirable silica hydroxyl effects are inhibited by polar groups, which can play a role in a wider area, enabling the application of one chromatographic column in a variety of modes. The Chinese patent application, application number 202110140190.7, publication No. 2021, 6 and 29, discloses a preparation method of a mixed mode liquid chromatography packing based on a single selector, wherein the surface chemical properties of the packing are homogeneous, and the embedded secondary amine groups greatly improve the separation effect of alkaline compounds in the reverse phase mode. Although secondary amine groups are less reactive toward aldehydes and ketones than primary amine groups, stationary phases containing secondary amines are also not stable when the analyte is a highly reactive electrophile, such as benzyl chloride, bromine, anhydride, isocyanate. In summary, the use of reverse phase silica matrix fillers modified with primary or secondary amine groups has been limited. Another interesting fact is that when the filler is well infiltrated by water due to the presence of these amino groups, and these amino groups have a strong tendency to break down the silyl ether bonds between the bonding phase and the silica matrix by the protic solvent in the mobile phase through hydrogen bonding with the residual silyl hydroxyl groups, the stationary phase of the filler is lost, and the chromatographic retention becomes progressively weaker. In order to further improve the stability of the filler while retaining the water-resistant property and the silicon hydroxyl shielding effect imparted by the amino group, it is very important to design a mixed mode chromatographic stationary phase based on cyclic polyamine. Disclosure of Invention 1. Technical problem to be solved The invention aims to solve the problems that primary amine or secondary amine group modified reverse phase silica gel matrix stationary phase is limited in use scene, and the silicon ether bond between the stationary phase bonding phase and the silica gel matrix is damaged by a proton solvent in a mobile phase, so that a filler stationary phase is lost, and the chromatographic retention capacity is gradually weakened, and provides a chromatographic stationary phase which has excellent stability and can be used for a long time within the pH range of 2.0-9