The design of advanced materials as heterogenous catalysts with well-defined and multifunctional active sites has attracted a lot of attention from industrial and scientific community in the past years. In this regard, the preparation of mesoporous hollow spheres (MHS) has received considerable interest, due to their interesting and versatile properties in different fields, such as heterogeneous catalysis or as platforms for drug delivery. A suitable catalytic application for such multifunctional structures is the ethanol to 1,3- butadiene (BD) one-step process, known from the ‘20s as Lebedev process. Therefore, the main driving force of HOLLOWs proposal is to establish new strategies to prepare an efficient mesoporous hollow spheres catalytic material to be used in the synthesis of 1,3 butadiene (BD), an important intermediate for the production of synthetic rubbers and other polymers, starting from renewable resources such as bioethanol.

The main driving force of HOLLOWs is to establish new strategies to prepare an efficient mesosporus hollow sphere catalytic material to be used in the synthesis of 1,3 butadiene (BD), an important intermediate for the production of synthetic rubbers and other polymers, starting from renewable resources such as bioethanol.

Project coordinator: Phd. Florentina Neatu -- Senior researcher II

Members:

Phd Stefan Neatu - Senior researcher II

Phd Nicoleta Apostol - Senior researcher II

Phd student - Assistent researcher

Phd Dana-Georgeta Popescu - Senior researcher II

Bioethanol butadiene (BD) formation is a complex chain of reactions requiring catalysts to have an optimal ratio between the amount and strength of acidic and basic centers and redox centers. Starting from these prerequisites, this project aims to develop and characterize acid-base materials that also contain redox centers for the conversion of ethanol into BD.

Stage 1- 2018

In this step, a series of 15 yolk-shell catalysts synthesized by three different methods were prepared. These materials had Mn as core and silica as shell. To vary the proportion of acid or base centers as well as redox centers, Mn was coupled with other transition metals, and silica was also coupled with other oxides to produce tertiary or quaternary materials. The materials prepared were characterized by different techniques: XRD, UV-Vis, Raman, FT-IR, SEM-EDX, XPS. Also, the first series of spherical materials containing only Mn and silica were tested in conversion of bioetanol in butadiene reaction.

Stage 2- 2019

Testing of quaternary materials  and also the  syntheses for structures containing silica modified with other acid oxides were continued. All activities were fully performed. The synthetic scientific report in .pdf format is available at the contracting unit.

Stage 3- 2020

The materials were optimized to obtain mesoporous spheres for quaternary structures as well, and the reaction parameters were improved to optimize the results for ethanol transformation. All activities were fully performed. The synthetic scientific report in .pdf format is available at the contracting unit.

Conferences

1. “Ternary and quaternary modified silica with transition metal for ethanol transformation”, F. Neatu, M.M. Trandafir, S. Neatu, M. Florea, 44th International Conference and Expo on Advanced Ceramics and Composites, 26-31 January 2020, poster.

2. “Mn-silica hollow spheres for ethanol transformation” M. M. Trandafir, S. Neaţu, M. Florea, F. Neaţu, 47th IUPAC World Chemistry Congress, 05.07.2019-13.07.2019, Paris, Franta, poster.

3.  “XPS analysis of core-shell catalysts for ethanol to 1,3 Butadiene reaction”, Amelia Elena Bocirnea, Mihaela Mirela Trandafir, Stefan Neatu, Mihaela Florea, Florentina Neatu, Kratos Users’ Meeting 2020, online 20-21 September 2020, poster.

Articles

1. “Behaviour of Molybdenum-Vanadium Mixed Oxides in Selective Oxidation and Disproportionation of Toluene” Gheorghita Mitran, Florentina Neaţu, Octavian D. Pavel, Mihaela M. Trandafir, Mihaela Florea, Materials 2019, 12, 748.

2. Crown-ether functionalized graphene oxide for metal ions sequestration, S. Petrescu, S. Avramescu, A.M. Musuc, F. Neatu, M. Florea, P. Ionita, Mater. Res. Bull, 2020, 122, 110643

3. “VAlPOs as Efficient Catalysts for Glycerol Conversion to Methanol”, G. Mitran, F. Neatu, S. Neatu, M.M. Trandafir, M. Florea, Catalysts, 2020, 10, 728; DOI: 10.3390/catal10070728;

4. “Highly Efficient Ultralow Pd Loading Supported on MAX Phases for Chemoselective Hydrogenation”, M.M. Trandafir, F. Neatu, I. M. Chirica, S. Neatu, A. C. Kuncser, E. I Cucolea, V. Natu, M. W. Barsoum, M. Florea, Catalysts, 2020, 10, 728; DOI: 10.3390/catal10070728;