Water based scale-up of CPO-27 synthesis for nitric oxide delivery

Abstract

The applicability of water-based reflux and room temperature synthesis processes for the production of CPO-27 MOFs, suitable for NO delivery applications, is investigated. NO adsorption, storage and release performance of products obtained under reflux conditions are comparable to those of equivalent samples synthesised from traditional solvothermal methods at small scale. Products obtained from room temperature processes show lower NO release capability, although the quantities that are released are still more than adequate for biomedical applications. Results also reveal differences for the first time in NO uptake, storage and release depending on whether Zn, Ni or Mg is employed. The results indicate that while the crystallinity of CPO-27(Zn) and CPO-27(Mg) is not affected by moving to lower temperature methods, the crystallinity of CPO-27(Ni) is reduced. Particle morphology and size is also affected. The low temperature processes are successfully demonstrated at 20 L and 100 L scale and the main problems encountered during scale-up are outlined. The 100 L scale is in itself an appropriate production scale for some niche biomedical products. Indeed, results indicate that this synthesis approach is suitable for commercial production of MOFs for this application field. We also confirm that BET surface area from nitrogen adsorption at 77 K is not a good indicator for successful adsorption of NO.

Template‐Directed Approach Towards the Realization of Ordered Heterogeneity in Bimetallic Metal–Organic Frameworks

“…Thesubsequent heating of this suspension at 120 8 8Cf or 3h led to the formation of highly crystalline Zn-MOF-74 as evidenced by PXRD and SEM analyses (Supporting Information, Figure S3). We believe that this high-temperature treatment and the presence of solvent molecules are critical to overcome intermolecular forces between polymer chains.These results also encouraged us to synthesize bimetallic MOF-74s starting from Mg 2+ or Ni 2+ impregnated polymer 1 under the same conditions.W e have carried out ( Figure 2a and the Supporting Information, Figure S4 a) PXRD analysis on Mg/Zn-MOF-74 and Ni/Zn-MOF-74 synthesized in the presence of 3.5 equiv of secondary metal ions.Both structures showed highly crystalline diffraction patterns,which are in good agreement with that of MOF-74 [13] synthesized through conventional homogeneous hydrothermal reaction. Thef ormation of bimetallic MOF-74 structures through 1D-to-3D transformation was further Figure S5).…”

Scalability of Continuous Flow Production of Metal–Organic Frameworks

“…Conventional MOF synthesis involves mixing solutions of the metal salt and organic linker in a sealed reactor vessel, which is subsequently heated for several hours under solvothermal conditions to promote the precipitation and growth of MOF crystals . Recently, improvements of this approach have emerged, reducing the complexity and cost of the synthesis by operating at atmospheric pressures without the need for specialized equipment . However, upscaling these solvothermal laboratory syntheses remains challenging due to long reaction times (hours or days), lack of versatility, and the low quality of materials ultimately obtained …”

“…[9,10] Recently,i mprovements of this approachh ave emerged, reducing the complexitya nd cost of the synthesis by operating at atmospheric pressures withoutthe need for specialized equipment. [11,12] However,u pscaling these solvothermal laboratory syntheses remains challengingd ue to long reaction times (hours or days), lack of versatility,a nd the low quality of materials ultimately obtained. [13,14] Variationso fs olvothermals yntheses employm ore efficient heatingm ethods such as microwave or ultrasonic radiation, which accelerate the rate of chemical reactiona nd consequently reduce the reaction time from days to hours.…”

Synthesis and crystallographic characterisation of Mg(H 2 dhtp)(H 2 O) 5 ·H 2 O

“…A particular goal of these studies is to understand the conditions required to get consistent crystallisation of the target materials and has to minimise potential impurity phases. [18] For example, it is known that, under solvothermal conditions, increasing the pH of the CPO-27-M (M = Mg [3] or Mn [4]) reaction mixture affords a separate, non-porous coordination framework of composition M(H 2 dhtp)(H 2 O) 2 (M = Mg [3] or Mn [19] ) that the authors denote as CPO-26-M. A recent study on the effect of pH on the one-pot reflux synthesis of CPO-27-M describes attempts to prepare CPO-27-Mg using a 2:1 ratio of NaOH:H 4 dhtp, however they report that no solid product could be obtained from this reaction system. [20] Herein we report the synthesis of a crystalline material of composition Mg(H 2 dhtp)(H 2 O) 5 ·H 2 O that may be obtained by lowering the amount of NaOH in reaction mixtures that is normally used to prepare CPO-27-Mg by the reflux method.…”

“…[20] Herein we report the synthesis of a crystalline material of composition Mg(H 2 dhtp)(H 2 O) 5 ·H 2 O that may be obtained by lowering the amount of NaOH in reaction mixtures that is normally used to prepare CPO-27-Mg by the reflux method. [18] All reagents were obtained from commercial sources and were used without further purification. …”