Research Team:

1. Natalia CANDU- director

2. Iunia PODOLEAN – young researcher

3. Magdi EL. FERGANI – PhD student

4. Nicolae GUZO – Master student

Project Summary:

Non-edible biomass is an attractive and sustainable raw material with a wide application, that can be applied in synthesis of liquid bio-fuels and value-added chemicals, which can minimize the dependence on oil and attenuate the concerns regarding the greenhouse gas emissions. Adipic acid (AA) is an important dicarboxylic acid on the nowadays market due to its extensive use in the production of Nylon 6.6 and polyurethanes. Despite this, there are many shortcomings associated to its current commercial production like cost and waste issues. An ideal sustainable alternative to the actually applied methodologies would be novel designed and developed catalytic materials for the conversion of glucose to AA. Such an approach is, however, expensive and time-consuming.

A faster and cheaper alternative could be achieved if the properties of the already dedicated industrial catalysts would be adapted to the biomass specificity. The main objective of the project is to develop novel and originally advanced materials with high catalytic performances for the conversion of glucose into AA. In order to achieve this goal the multifunctional active sites materials, with the design which follows the core-shell (CS), yolk-shell (YS) and zeolite catalyst structure was developed. The catalytic phase and the nature of active sites were established in connection with chemical composition of glucose capable for the selective catalytic transformation to glucaric acid (GA).

The synthesis of such phases and the establishment of the optimal one for each type of the corresponding reaction step in the conversion of glucose to AA constitute the goals to reach the main objective.

The implementation degree of the project:

Phase I/2020(01.09.2020-31.12.2020): Synthesis and characterization of magnetic amino-functionalized “core-shell” catalysts

Activity 1.1. Synthesis of monometallic amino-functionalized “core-shell” catalysts using magnetite as “core” and SiO₂, ZrO₂ or CeO₂ functionalized with APTES as “shell”.

Activity 1.2. Characterization of monometallic amino-functionalized “core-shell”catalysts.

Activity 1.3. Oxidation of glucose to glucaric acid using “core-shell”catalysts.

Summary of the research report (Phase I) - 2020

Monometallic catalysts with transition and noble metals on magnetite-oxide-core support (Si, Ce Zr) were synthesized. Characterization methods demonstrated both: the successful synthesis of the support, its functionalization with amino groups and the impregnation-precipitation of metal species (Schema 1).

Schema 1. Synthesis of monometallic ‘’core-shell’’ catalysts.

The experimental results obtained in this stage are basic elements in order to further undergo the experimental activities of the next phase (Phase II / 2021).

PhaseII/2021(01.01.2021-31.12.2021): Synthesis and characterization of amino-functionalized magnetic “yolk-shell” and “core-shell” catalysts. Catalytic conversion of glucose to glucaric acid, using water as a solvent, in the presence of “core-shell”and “yolk-shell” catalysts. Correlation of the structural characteristics of the catalysts with their performance.

In order to accomplish the proposed objectives of this phase, the following activities were carried out:

Activity 2.1. Synthesis of bimetallic amino-functionalized „core-shell”catalysts, using magnetite as „core” and SiO₂, ZrO₂ or CeO₂ functionalized with APTES as „shell”.

Activity 2.2. Synthesis of monometallic amino-functionalized ”yolk-shell” catalyst.

Activity 2.3. Synthesis of bimetallic amino-functionalized “yolk-shell” catalyst.

Activity 2.4. Characterization of mono- and bimetallic amino-functionalized “core-shell”and “yolk-shell” catalysts.

Activity 2.5. Oxidation of glucose to glucaric acid using “core-shell”and “yolk-shell”catalysts.

Activity 2.6. Correlation of the catalytic performance with the catalytic properties.

Activity 2.7. Dissemination of the obtained results by participating at national or international conferences in the field.

Summary of the research report (Phase II)- 2021

The main objective of this stage was to investigate new methods and materials for the synthesis of bimetallic catalysts with transition and noble metals on amino groups functionalized “core-shell” magnetite-oxide (Si, Ce Zr) support, as well as mono- and bimetallic "yolk-shell" type-materials (Schema 2). The characterization methods applied to the obtained materials demonstrated both: the successful synthesis of the support and its functionalization with amino groups and the impregnation-precipitation of metal species.

Schema 2. Synthesis of monometallic ‘’yolk-shell’’ catalysts.

Catalytic performance was correlated with catalytic properties. The MSA@Co5 catalyst showed the best catalytic efficiency for D-glucose oxidation under mild reaction conditions (40⁰C and 10h) in the presence of the benign H₂O₂ oxidation agent. A high conversion of D-glucose (86.2%) for selectivities to GLU (gluconic acid) of 33.8% and GLUU (glucuronic acid) of 14.6% were obtained in the presence of this catalyst. Moreover, the catalyst can be easy recovered by a simple external magnet and reused at least three consecutive runs, with similar catalytic efficiency. These results open new perspectives in the further application of transition metals in this type of oxidation reactions, still governed by noble metal-based catalysts. Among SiO₂, CeO₂ and ZrO₂, SiO₂ has been shown to be the appropriate shell for magnetite providing a high stability of the catalyst. In addition, the presence of APTES exhibited a positive contribution for a better distribution of cobalt oxide, leading to a high catalytic efficiency and also to good catalyst stability.

The results were disseminated by participating at the international conference and a workshop with two oral presentations and one poster.

Phase III/2022(01.01.2022-31.08.2022): Development of new catalytic materials structurally adapted to the specific properties of biomass. Catalytic conversion of glucaric acid to adipic acid, using water as a solvent. Correlation of the catalytic performance with the properties of the catalysts.

In order to accomplish the proposed objectives of this phase, the following activities were carried out:

Activity 3.1 Synthesis of bimetallic Me-ReOx/DeAl-BEA catalysts.

Activity 3.2 Synthesis of trimetallic PtMe-ReOx/DeAl-BEA catalysts.

Activity 3.3 The characterization of the synthesized zeolites catalysts.

Activity 3.4 Hydrodeoxygenation of glucaric acid to adipic acid.

Activity 3.5 Catalytic properties-catalytic performances correlation.

Activity 3.6 Dissemination of the obtained results through participation to congresses in the area and publishing an ISI paper (IF>1.5).

Summary of the research report (Phase III) - 2022

Hydrodeoxygenation (HDO) using heterogeneous catalysts (eg. metal, acid, and bifunctional sites) has received considerable attention as a way of converting biomass-derived oxygenates into renewable fuels and chemicals. This reaction is complex and involves a combination of different reactions such as hydrogenation, hydrogenolysis, decarbonylation, and dehydration.  Bimetallic and trimetallic catalysts with transition (Ni) and noble metals (Ir or Pt) on BEA zeolites with different Si/Al ratios were synthesized for this type of reaction. Characterization methods demonstrated the impregnation of metal species inside the pores of deluminated zeolites, without a collapse of the support structure or a complete pore blocking.

The one-step conversion of mucic acid to adipates (see Schema 3) was achieved in good yield (≥82%) through HDO using bimetallic heterogeneous catalyst with isopropanol or 3-propanol as solvent and reductant, after 24h and at 220ºC. Catalytic performance was correlated with catalytic properties. The best candidate in terms of conversion and selectivity was Pt-ReOx/BEA.
          

   Schema 3. One-pot conversion of mucic acid to adipates.

The obtained results were disseminated by participating at the international conference with one oral presentation and one poster.

Considering the above and the established objectives, it can be concluded that all contractual obligations were fulfilled during the reported period of the research project.

Dissemination (with aknowledgements):

Papers in scientific journals:

1. I. Podolean, M. El Fergani, N. Candu*, S. M. Coman, V. I. Parvulescu*, Selective oxidation of glucose over transitional metal oxides based magnetic core-shell nanoparticles, acceptat in Catalysis Today, doi.org/10.1016/j.cattod.2022.08.028.

2. M. El Fergani, N. Candu, I. Podolean, B. Cojocaru, M. Tudorache, V. I. Parvulescu, S.M. Coman*, Catalytic hydrotreatment of humins wastes over bifunctional Pd-based zeolite catalysts, submited in Catalysts.

3. I. Podolean, B. Cojocaru, V. I. Pârvulescu, S. Abdi, M. Shamzhy, J. Čejka, Lactic acid conversion to lactides over Al-substituted UTL and IPC zeolites, submited in Applied Materials Today.

Communications:

1. M. El Fergani, I. Podolean, S. M. Coman, V. I. Parvulescu, N. Candu, ”Non-precious metal-based magnetic catalystsusing for theproduction of Diacids” 5-th EuChemS Conference on Green and Sustainable Chemistry (5-thEuGSC), 26-29 september 2021 (Virtual Conference) Greece. (Oral Presentation).

2. N. Candu, I. Podolean, S. Marinică, M. El Fergani, V.I. Parvulescu, S.M. Coman, ”Ru-based magnetic catalysts for selective oxidation and reductive amination of biomass” 5-th EuChemS Conference on Green and Sustainable Chemistry (5-thEuGSC), 26-29 september 2021 Greece (Virtual Conference). (Poster).

3. M. El Fergani, I. Podolean, N. Guzo, S. M. Coman, M. Tudorache, V. I. Parvulescu, N. Candu, ”Magnetic core-multi-shell nanocomposites for green oxidation process of glucose” Workshop CoSolMat (Virtual Workshop), 11-15 october 2021, Bucharest, Romania. (Oral Presentation).

4. M. El. Fergani, I.Podolean, S. M. Coman, V. I. Parvulescu, N. Candu, Selective oxidation of glucose over transitional metal oxides based magnetic core-shell nanoparticles, RomCat Conference 2022, The 13th International Symposium of the Romanian Catalysis Society, Baile Govora, Romania, 22-24 june 2022.(Oral Presentation).

5. I. Podolean, J. Zhang, M. Shamzhy, V. I. Pârvulescu, J. Čejka, Germanosilicate large-pore zeolites: the role of the nature of the acid sites and strength, RomCat Conference 2022, The 13th International Symposium of the Romanian Catalysis Society, Baile Govora, Romania, 22-24 june 2022.(Poster).