Preparation of Zr-MOF Catalyst and its application in synthesis of trimethylolethane

doi:10.21203/rs.3.rs-4972276/v1

Twelve metal-organic skeleton (MOFs) polymers were catalyzed and screened. Zr-MOF-J was selected as the best catalyst and characterized. We use a variety of analytical techniques to thoroughly characterize the best performing catalysts including scanning electron microscopy (SEM), Brunner−Emmet−Teller (BET) measurements, Fourier transform infrared spectroscopy (FTIR), Nuclear Magnetic Resonance (13C-NMR) and thermogravimetric analysis (TGA). The characterization results unequivocally demonstrated that the synthesized catalyst was a porous polymer with exceptional heat stability. The catalytic performance of the catalyst was evaluated by synthesis of trimethylolethane from formaldehyde and propionaldehyde. The optimal reaction conditions were as follows: the catalyst amount accounted for 20%（wt%） of propionicaldehydemass, the reaction temperature was maintained at 65 ℃, the reaction time was 2.5 h, the molar ratio of propionaldehyde to formaldehyde was 1:3. Under these optimal conditions, the conversion rate of propionaldehyde was up to 98.34% and the selectivity of trimethylolethane was 86.9%. Notably, the catalytic activity did not significantly diminish even after being reused five times.

MOFs

Polymers

Catalyst

Trimethylolethane

Trimethylolethane (TME) is a novel pentane-structured polyol with three highly active hydroxyl groups. At present, it is mainly used in the synthesis of coupling reagent, crosslinking agents, phase change materials, etc. ^[1–5] Due to its high heat of phase change, small volume change, non-corrosive property and high thermal efficiency excellent characteristics have attracted wide attention and in-depth research. And, its application fields are constantly expanded, which includes apparel, medical, military, and other various industries.

TME synthesis usually goes through two reaction processes. The first stage: propionaldehyde and formaldehyde condense to form 2,2-Dimethylolpropanal. The second stage: 2,2-Dimethylolpropanal and excess formaldehyde are obtained by Cannizzario reaction under the action of the same catalyst. ^[6] Due to the high cost and low utilization rate of catalysts, the economic benefits of such catalysts are gradually decreasing. ^[7] The main synthetic methods of TME in industry are condensation hydrogenation and condensation disproportionation. Since the process of condensation hydrogenation requires high-pressure equipment, it has been gradually phased out. Condensation disproportionation adds complexity to the process because the by-products are not easily separated and the reaction conditions are harsh, hindering their wide range of applications. ^[8–12] Therefore, it is imperative to develop catalysts that possess facile separation, high catalytic activity, and substantial economic viability. Metal organic frameworks (MOF) are a kind of porous coordination polymer formed by connecting metal atoms in the center of structure with ligands. ^[13] They have rich porosity, good stability, good catalytic activity and strong designability. ^[14–16] UIO-66 has important applications in adsorption, ^[17,18] separation, ^[19,20] catalysis, ^[21,22] materials, ^[23,24] and sensing. ^[25,26] Liu et al. ^[27] prepared UIO-66 and UIO-66-NH₂. They determined the number of basic sites and studied their catalytic effects. They found that the basic site could promote the reaction in a positive direction. The problem of a small amount of 1,3-butadiene in the flow of petroleum cracking butene was solved. Wang et al. ^[28] synthesized UiO-66 (Zr/Ti) with different Ti contents in a one-step method. The results showed that Ti⁴⁺ content had a significant effect on catalytic polycondensation reaction. Abdelhamid. ^[29] synthesized UIO-66 by solvothermal method. He found that UIO-66 has a large specific surface area and acidic sites, which can promote the positive movement of the reaction. It provides a new method for hydrogen production by hydrolysis.

In this study, based on our previous research(UIO-66 ^[30]), we synthesized an ionic liquid porous polymer catalyst Zr-MOF-J by introducing CH₃ONa into UIO-66. The traditional synthesis method of UIO-66 is the reaction of terephthalic acid and zirconium tetrachloride. The reaction principle is that two carboxyl groups and zirconium complex reaction to form UIO-66 structure. We synthesized dicarboxylic acid ionic liquid to replace terephthalic acid, and reacted with zirconium chloride to form UiO-66 functional ionic liquid. Then the chloride ionic liquid is exchanged with the active group methanoxy by ion exchange. Generation of ionic liquid, the functionalized UIO-66 catalyst has both MOF structure and ionic liquid activity. At the same time, we deeply studied the effects of reaction time, reaction temperature, catalyst dosage and molar ratio of raw material on the reaction, as well as the stability of the catalyst.

2.1. Materials

Glutamic acid(purity, 98.0%), 4-(Chloromethyl)benzoic acid(purity, 98.0%), ferric chloride(purity, 45.0%), propanal(PA, purity, 97.0%), aluminium chloride(purity, 99.0%), and zircomiun tetrachloride(purity, 99.9%) were purchased from Shanghai Aladdin Company. Propionic acid(purity, 99.5%), formaldehyde(FA, purity, 37%), sodium methoxide(purity, 98.0%), sodium silicate(purity, 35.0%-40%) and ethanol(purity, 95.0%) were purchased from were gained from Shanghai Macklin Co. Ltd

2.2. Synthesis of IL

Glutamic acid (7.35 g, 0.05 mol) and 4-(Chloromethyl) benzoic acid (8.52 g, 0.05 mol) were dissolved in 50 mL of anhydrous ethanol, and the mixture was stirred. The resulting solution was heated and reacted in an oil bath with condensation reflux at 80 ℃ for 10 h.

2.3. Synthesis of the N-MOF

The above-mentioned ionic liquid, ZrCl₄ (5.826 g, 0.025 mol), and solvent were added into a three-neck flask equipped with magnetic stirring. The reaction was carried out at 120 ℃ in an oil bath with condensation reflux for 4 h. After completion, the resulting products were cooled, filtered, washed once or twice with ethanol, and then dried. The final product, a gray solid was named Zr-MOF. In parallel, other MOFs were synthesized by substituting ZrCl₄ with FeCl₃ and AlCl₃, and they were named Fe-MOF, Al-MOF, respectively.

2.4. Synthesis of the N-MOF-X

The Zr-MOF and an appropriate amount of ethanol were added in a 250 mL three-necked flask. Sodium methoxide, dissolved in ethanol, and was then introduced into the flask. The resulting mixture was subjected to a reaction at 100 ℃ for 5 h. After the reaction, the solid was separated by filtration, washed with ethanol and distilled water, and subsequently dried. The resulting product, in the form of a white solid powder, was designated as Zr-MOF-J. The synthesis of Zr-MOF-J was illustrated in Scheme 1. Substituting sodium methoxide with other substances for ion exchange led to the creation of other polymers. These polymers were prepared following the same method as described above, with Zr-MOF was replaced by other metal organic frameworks such as Fe-MOF and Al-MOF. The polymer were obtained by reacting sodium methoxide, sodium silicate, and propionic acid (refer to Table 1).

Table 1

Type and name of the polymer
Reagent	Sodium methoxide	Sodium silicate	Propanoic acid
Zr-MOF	Zr-MOF-J	Zr-MOF-G	Zr-MOF-B
Fe-MOF	Fe-MOF-J	Fe-MOF-G	Fe-MOF-B
Al-MOF	Al-MOF-J	Al-MOF-G	Al-MOF-B

2.5 Preparation of TME

A formaldehyde solution (37 wt%, 2.43 g, 0.03 mol) and catalyst Zr-MOF-J (20% of propionaldehyde mass) were added into a three-neck flask equipped with magnetic stirring. Subsequently, propionaldehyde (0.58 g,0.01 mol) was added dropwise at 30 ℃ for 2 h. Following this initial phase, the temperature was adjusted, and the reaction continued for 2.5 h at 65 ℃. Upon completion of the reaction, the catalyst was filtered, washed and dried for reuse. Product yield was determined using the internal standard method via gas chromatography. (GC7900, Shanghai tianmei scientific instrument co., ltd). FID detector is used for gas chromatography detection, and the conditions are as follows: the inlet temperature is 250 ℃, the detector temperature is 250 ℃, and the column box temperature is programmed. The column temperature program is: the initial column temperature is 45 ℃, and the temperature rises from 20 ℃/min to 200 ℃ for 11.750 min. Various reaction conditions were investigated, including different amount of catalyst (16%, 18%, 20%, 22%, 24%), varying reaction time (0.5 h, 1.5 h, 2.5 h, 3.5 h, 4.5 h), diverse reaction temperature (35 ℃,45 ℃,55 ℃,65 ℃, 75 ℃), and molar ratio (1:1, 1:2, 1:3, 1:4, 1:5).

3.1. Screening of catalyst

The 12 catalysts synthesized as above described employed in the preparation of the TME. The selectivity data was shown in Fig. 1. The results clearly showed that the catalytic performance of Zr-MOF-J was the most favorable. Consequently, in the future experiments, we focused on using Zr-MOF-J to investigate the impact of various factors on TME synthesis.

3.2. Characterization

3.2.1 FTIR

As shown in Fig. 2, the FTIR of IL, Zr-MOF and Zr-MOF-J were presented, it can be seen that the peak observed at 1283 cm^− 1 corresponded to the characteristic peak of C-N bond ^[31], indicating the successfully synthesis of Ionic liquid. Furthermore, the peak at 1705 cm^− 1 can be attributed to the characteristic peak of C = O group ^[32]. In comparison with IL, Zr-MOF exhibited a characteristic peak at 717 cm^− 1, associated with Zr-O ^[30], and characteristic peaks at 1608 cm^− 1 and 1429 cm^− 1, which are linked to the C-O-O group ^[33] .

3.2.2 SEM

The structure and morphology of Zr-MOF-J were examined using SEM. As depicted in Fig. 3(b), the catalyst exhibited evident pores and an irregular pore structure, indicating the presence of a porous material. Notably, the polymer displays an irregular honeycomb structure, distinguishing it from the traditional UIO-66 structure. In Fig. 3(a) ^[30] the structure of UIO-66 appears as a spherical structure, highlighting the morphological changes that occurred during the preparation of Zr-MOF-J. These observations affirm the porous nature of the material.

3.2.3 Thermogravimetric analysis (TGA)

As shown in Fig. 4, the TG curve exhibited a relatively gentle slope. Calorimetric analysis results revealed that the process can be divided into three distinct stages. The first stage, spanning from 0 to 288 ℃, is characterized by a gradual weight loss. At a temperature of 288 ℃, the Zr-MOF-J experienced a weight loss rate of 10%, likely attributed to the removal of most of the adsorbed water (comprising combined water and free water) present on the catalyst. The second stage, occurring between 288 ℃ and 566 ℃, was marked by a significant and rapid weight loss. When the temperature reached 566 ℃, the weight loss rate of Zr-MOF-J reaches 40%, It may be the decomposition of aromatic compounds and the pyrolysis of terminal residues of polymers. The third stage, ranging from 566 ℃ to 1000 ℃, is relatively stable compared to the previous stages. But there is still a decline, it may be due to the carbonization of the main chain

3.2.4 Nitrogen adsorption and desorption analysis

According to the data presented in Table 2, the surface area and pore volume of Zr-MOF-J measure 68.602 m²/g and 0.134 cm³/g, respectively. These findings clearly establish that Zr-MOF-J qualifies as a porous catalyst.

As shown in Fig. 5, Zr-MOF-J exhibited a type Ⅴ isothermal, with a substantial increase in adsorption occurring at a relative pressure range of 0.8 to 1.0. The pore size distribution analysis indicated that the pore size distribution of Zr-MOF-J was not uniform, encompassing both large pores and mesopores. Table 2 presented the data indicating that the surface area and pore volume of Zr-MOF-J are 68.602 m²/g and 0.134 cm³/g, respectively. These findings effectively demonstrated that Zr-MOF-J possessed the characteristics of a porous catalyst.

Table 2

Specific surface area
Pore Volume(cm³/g)	D_DFT (nm)	S_BET(m²/g)
0.134	3.169	68.602

3.2.5 ¹³C-NMR

The results of the ¹³C MAS NMR are presented in Fig. 6. Figure 6(a) displays the standard spectrum of the polymer, while Fig. 6(b) represents the measured graph. The chemical shift at 4.28 ppm is associated with the carbon atom in -CH2-. The chemical shifts of 20.25 and 22.57 ppm are related to the carbon atoms in the carboxy-linked -CH2-. The chemical shift at 35.85 ppm is associated with the carbon atom in -CH3. The chemical shift at 50.86 ppm is associated with the carbon atom in a secondary amine.While the chemical shift at 120.19 and 132.36 ppm is attributed to the carbon atom in the benzene ring. The chemical shifts at 163.31 ppm are ascribed to the carbon atom in a carboxyl group. A comparison between Figs. 6(a) and 6(b) reveals the successful synthesis of the polymer.

3.3 Catalytic performance

3.3.1 Catalyst dosage

We investigated the effect of catalyst amount while keeping other reaction conditions constant (reaction time 3.5 h, reaction temperature 45 ℃ and the molar ratio of propionaldehyde and formaldehyde 1:1) were immutable. As illustrated in Fig. 8, a low catalyst amount resulted in slow reaction kinetics and an extended reaction period, causing incomplete conversion within the designated time and a consequently low yield of TME. Conversely, an excessive catalyst amount led to the unwanted disproportionation of formaldehyde and n-propionaldehyde, resulting in reduced overall reaction yield. At this juncture, the propionaldehyde conversion rate reached 54.01%, with a TME selectivity of 56.66%. Therefore, to strike a balance between catalyst activity and economy, the optimal catalyst amount was determined to be 20 wt%.

3.3.2 Reaction temperature

The reaction temperature had a significant impact on product yield, and its influence was examined under constant conditions (reaction time: 3.5 hours, catalyst dosage: 20 wt%, and a molar ratio of propionaldehyde to formaldehyde: 1:1). Figure 9 illustrated the relationship between reaction temperature and TME yield. At lower temperatures, the yield of trimethylolethane was low. With an increase in temperature, the yield increased proportionally. However, when the reaction temperature exceeded 65 ℃, the yield began to decrease. This decrease may be attributed to the temperature not only promoting the main reaction but also accelerating unwanted side reactions. Therefore, it is essential to carefully control the reaction temperature to optimize yield. The optimal reaction temperature was found to be 65 ℃.

3.3.3 Reaction time

The influence of reaction time on conversion and selectivity is of significant importance. An investigation into the effects of reaction time while keeping other reaction conditions constant (reaction temperature at 65 ℃, catalyst dosage at 20 wt%, and a molar ratio of 1:1 for propionaldehyde and formaldehyde) was conducted. As shown in Fig. 10, when the reaction time was too short, the condensation reaction between n-propionaldehyde and formaldehyde remained incomplete. The yield of TME increased with longer reaction time. However, when the reaction time exceeded 2.5 h, the yield of TME began to decrease. This decrease can be attributed to the fact that, during this extended period, the reaction of raw material had nearly reached completion. Therefore, the optimal reaction time was determined to be 2.5 h, with a conversion rate was of 70% and a selectivity of 63%.

3.3.4 Molar ratio of propionaldehyde and formaldehyde

The molar ratio of materials also plays a crucial role in determining conversion and selectivity. Considering economic constraints and the volatile nature of formaldehyde, the effect of molar ratio of propionaldehyde and formaldehyde was studied. The other reaction conditions ( reaction time 2.5 h, reaction temperature 65 ℃, catalyst dosage 20 wt% ) remained unchanged. The results were showed in Fig. 11. As the molar ratio of formaldehyde to n-propionaldehyde increased, the yield of trimethylolethane continued to rise. However, when the molar ratio of formaldehyde to propionaldehyde exceeded 1:3, the product's yield exhibited no significant change. Additionally, an excessive amount of formaldehyde would result in raw material wastage and an increase in the formation of by-products. Therefore, the optimal material ratio is n(propionaldehyde): n(formaldehyde) = 1:3.

3.3.5 Catalyst repeatability

The reproducibility of the catalyst was investigated under the optimal reaction conditions. After each reaction, the catalyst was filtered, washed and dried for the next cycle. The results were showed in Fig. 12. It is evident that the conversion and selectivity did not significantly decrease even after being reused for 5 cycles. This observation indicates that the catalyst exhibits excellent stability and reproducibility.

3.3.6 Comparison with other catalysts

As indicated in Table 3, the choice of catalyst had a pronounced impact on the selectivity of TME. In the absence of a catalyst, the selectivity for TME was nearly 0. However, the comparative results highlight the high catalytic activity of our catalyst, achieving a propionaldehyde conversion rate of 98.34% and a TME selectivity of 86.9%. Furthermore, the solid-state nature of the catalyst allows for easy separation.

Table 3

Effects of the different catalyst types
Catalyst	Yield (%)	refs
Zr-MOF	25.84	this study
Zr-MOF-J	85.46	this study
Aqueous	42.36	[34]
Ca(OH)₂	62.18	[34]
Na₂CO₃	47.64	[34]
Triethylamine	15.01	[34]

Twelve metal-organic skeleton (MOFs) polymers were catalyzed and screened.Zr-MOF-J was selected as the best catalyst and characterized. The characterization results showed that the catalysts were porous polymer and high thermal stability. The catalytic performance of the catalyst was evaluated in the synthesis of TME from formaldehyde and propionaldehyde. The optimal reaction conditions were as follows:: the catalyst amount was 20 wt% (based on propionicaldehyde mass), the reaction temperature was 65 ℃, the reaction time was 2.5 h, the ratio of propionaldehyde and formaldehyde was 1:3. Under these optimal conditions, the conversion rate of propionaldehyde was up to 98.34% and the selectivity of trimethylolethane was 86.9%. The catalytic activity did not reduce obviously after being reused for 5 times. These results showed that these catalysts hold great promise as metal-organic framework polymer catalysts.

Data availability

All data generated or analysed during this study are included in this published article

Notes

The authors declare no competing financial interest.

Acknowledgments

This research was supported by the national natural science foundation of China (NO. 21106032), natural science foundation of Hebei province (NO. B2021103012).

Author contributions

Xin Wang: Conceptualization, Data Curation, Formal Analysis, Methodology, Validation, Writing- Original Draft, Writing- Review & Editing.

Cong Li: Writing- Review & Editing.

Yuheng Xie: Writing- Review & Editing.

Jiangxin Li: Writing- Review & Editing.

Yajuan Wang: Writing- Review & Editing.

Juan Zhang: Writing- Review & Editing, Funding Acquisition.

Declarations Conflict of interest: The authors declare no conflict of interest. Supplementary information Not Applicable Data and code availability Not Applicable

Ethical approval Not Applicable.

Chen YJ, Chen HH (2006) 1, 1, 1-Tris (hydroxymethyl) ethane as a new, efficient, and versatile tripod ligand for copper-catalyzed cross-coupling reactions of aryl iodides with amides, thiols, and phenols. Org. Lett. 8(24) 5609-5612.
Suzuki H, Wada N, Komoda Y, Usui H, Ujiie S (2009). Drag reduction characteristics of trimethylolethane hydrate slurries treated with surfactants. Int. J. Refrig. 32(5) 931-937.
Zhang N, Jing Y, Song Y, Du Y, Yuan Y (2020) Thermal properties and crystallization kinetics of pentaglycerine graphene nanoplatelets composite phase change material for thermal energy storage. Int. J. Energy. Res. 44(1): 448-459.
Li Z, Li Y, He M, Wang W, Li J (2022) Effects of the species of crosslinking reagents on the structures and properties of biodegradable poly (butanediol sebacate‐butanediol terephthalate) copolyester. J. Appl. Polym. Sci. 139(20): 52145.
Yamazaki M, Sasaki C, Kakiuchi H, Osano YT, Suga H (2002) Thermal and structural characterization of trimethylolethane trihydrate. Thermochim. Acta. 387(1): 39-45.
Bai G, Peng H (2007) Research progress of polyols based on cross aldol condensation reaction. Fine and Specialty Chemicals, (01): 4
Laemmle GJ, Milligan JG, Peppel WJ (1960) Trimethylolethane from Propionaldehyde and Formaldehyde. Ind. Eng. Chem. 52(1): 33-36.
Liu W, Park Z, Qi X (2003) Development of trimethylolpropane propane synthesis process Elastomers, (05): 53.
Robeson MO (1957) Continuous production of trimethylolethane US2790837.
Gottesman ROY T (1957) Recovery of trimethylolethane. US2806889.
Immel O, Schwarz HH, Quast H, (1985) Process for the preparation of trimethylolpropane. US4514578.
Erlandsson L (1997) Process for recovery and refining of trimethylolethane. WO9749657.
Zhang Y, Yu X, Hou Y, Liu C, Xie G, Chen X (2024) Current research status of MOF materials for catalysis applications. Mol. Catal. 555: 113851
Xie LS, Skorupskii G, Dinca M (2020) Electrically conductive metal–organic frameworks. Chem. Rev. 120(16): 8536-8580.
Dai F, Luo J, Zhou S, Qin X, Liu D, Qi H (2021) Porous hafnium-containing acid/base bifunctional catalysts for efficient upgrading of bio-derived aldehydes. Journal of Bioresources and Bioproducts, 6(3): 243-253.
Hayat A, Rauf S, Al-Alwan B, El-Jery A, Almuqati N, Melhi S, Lv W (2024) Recent advance in MOFs and MOF-based composites: synthesis, properties, and applications. Mater. Today. Energy. 101542
Saha D, Deng S (2010) Ammonia adsorption and its effects on framework stability of MOF-5 and MOF-177. J. Colloid. Interf. Sci. 348(2): 615-620.
Ansone-Bertina L, Ozols V, Arbidans L, Dobkevica L, Sarsuns K, Vanags E, Klavins M (2022) Metal–Organic Frameworks (MOFs) containing adsorbents for carbon capture. Energies. 15(9): 3473
Kadioglu O, Keskin S (2018) Efficient separation of helium from methane using MOF membranes. Sep. Purif. Technol. 191: 192-199.
Liu X, Yue T, Qi K, Qiu Y, Xia B, Guo X (2020) Metal-organic framework membranes: From synthesis to electrocatalytic applications. Chinese Chem. Lett. 31(9): 2189-2201.
Valdebenito G, Gonzaléz-Carvajal M, Santibañez L, Cancino P (2022) Metal–organic frameworks (MOFs) and materials derived from MOFs as catalysts for the development of green processes. Catalysts. 12(2): 136
Luz I, i Xamena F, Corma A (2010). Bridging homogeneous and heterogeneous catalysis with MOFs:“Click” reactions with Cu-MOF catalysts. J. Catal. 276(1): 134-140.
Sun N, Zhang X, Deng C (2015) Designed synthesis of MOF-derived magnetic nanoporous carbon materials for selective enrichment of glycans for glycomics analysis. Nanoscale. 7(15): 6487-6491.
Kostecki R, Ebendorff-Heidepriem H, Warren-Smith SC, Monro TM (2013) Predicting the drawing conditions for microstructured optical fiber fabrication. Opt. Mater. Express, 4(1): 29-40.
Hu Z, Deibert BJ, Li J (2014) Luminescent metal–organic frameworks for chemical sensing and explosive detection. Chemical Society Reviews, Chem. Soc. Rev. 43(16): 5815-5840.
Lustig WP, Mukherjee S, Rudd ND, Desai AV, Li J, Ghosh SK (2017) Metal–organic frameworks: functional luminescent and photonic materials for sensing applications. Chem. Soc. Rev. 46(11): 3242-3285.
Liu L, Yu L, Zhou X, Xin C, Sun S, Liu Z, Tai X (2022) Comparative study of Pd–Ni bimetallic catalysts supported on UiO-66 and UiO-66-NH2 in selective 1, 3-butadiene hydrogenation. Nanomaterials. 12(9): 1484
Wang J, Zhang S, Han Y, Zhang L, Wang Q, Wang G, Zhang X (2022) UiO-66 (Zr/Ti) for catalytic PET polycondensation. Mol. Catal. 532: 112741
Abdelhamid HN. (2020) UiO-66 as a catalyst for hydrogen production via the hydrolysis of sodium borohydride. Dalton. T. 49(31): 10851-10857.
Shan Q, Zhang J, Wang Y, Liu W. (2022) Preparation of ionic liquid-type UiO-66 and its adsorption desulfurization performance. Fuel. 312: 122945
Wang Y, Zhang J, Shan Q, Liu W (2022) Preparation of porous polyaminobenzenesulfonic acid and synthesis of glycerol monolaurate. Chem. Pap. 1-15.
Deng Y, Li X, Wang R (2021) Carboxyl functional group-assisted defects passivation strategy for efficient air-processed perovskite solar cells with excellent ambient stability. Sol. Energ. Mat. Sol. C. 230: 111242
Seo PW, Ahmed I, Jhung SH (2016) Adsorptive removal of nitrogen-containing compounds from a model fuel using a metal–organic framework having a free carboxylic acid group Chem. Eng. J. 299: 236-243.
Wang X (2009) Study of synthesis technology of trimethylolethane Fine chemical intermediate, 29(6): 9

Scheme 1 and 2 are available in the Supplementary Files section.

floatimage1.png
Graphica Abstarct
SCHEME1.png
Scheme 1 Synthesis of Zr-MOF-J
SCHEME2.png
Scheme 2 The synthesis process for MAL

Preparation of Zr-MOF Catalyst and its application in synthesis of trimethylolethane

Status:

Version 1

Abstract

Figures

1. Introduction

2. Experimental

2.1. Materials

2.2. Synthesis of IL

2.3. Synthesis of the N-MOF

2.4. Synthesis of the N-MOF-X

2.5 Preparation of TME

3. Results and discussion

3.1. Screening of catalyst

3.2. Characterization

3.2.1 FTIR

3.2.2 SEM

3.2.3 Thermogravimetric analysis (TGA)

3.2.4 Nitrogen adsorption and desorption analysis

3.2.5 ¹³C-NMR

3.3 Catalytic performance

3.3.1 Catalyst dosage

3.3.2 Reaction temperature

3.3.3 Reaction time

3.3.4 Molar ratio of propionaldehyde and formaldehyde

3.3.5 Catalyst repeatability

3.3.6 Comparison with other catalysts

4. Conclusions

Declarations

References

Scheme

Supplementary Files

Status:

Version 1

Preparation of Zr-MOF Catalyst and its application in synthesis of trimethylolethane

Status:

Version 1

Abstract

Figures

1. Introduction

2. Experimental

2.1. Materials

2.2. Synthesis of IL

2.3. Synthesis of the N-MOF

2.4. Synthesis of the N-MOF-X

2.5 Preparation of TME

3. Results and discussion

3.1. Screening of catalyst

3.2. Characterization

3.2.1 FTIR

3.2.2 SEM

3.2.3 Thermogravimetric analysis (TGA)

3.2.4 Nitrogen adsorption and desorption analysis

3.2.5 13C-NMR

3.3 Catalytic performance

3.3.1 Catalyst dosage

3.3.2 Reaction temperature

3.3.3 Reaction time

3.3.4 Molar ratio of propionaldehyde and formaldehyde

3.3.5 Catalyst repeatability

3.3.6 Comparison with other catalysts

4. Conclusions

Declarations

References

Scheme

Supplementary Files

Status:

Version 1

3.2.5 ¹³C-NMR