Data on the synthesis and characterizations of carboxylated carbon-based catalyst from eucalyptus as efficient and reusable catalysts for hydrolysis of eucalyptus.

The presented article reports the preparation and characterization of heterogeneous carbon catalyst enriched with carboxylic group denoted as (ECS) from Eucalyptus as an efficient catalyst for the hydrolysis of woody Eucalyptus biomass. The fabrication process is based on the ball milling of Eucalyptus as a carbon source in the presence of dry ice as an oxidizing agent followed by acidification with the assistance of hydrochloric acid. The data are including the schematic for the full synthesis steps and characterization tools in addition to the thermogravimetric analysis and proton nuclear magnetic resonance analysis for the ECS catalyst. Meanwhile, the catalytic performance of ECS catalyst towards the hydrolysis of Eucalyptus was measured under different temperatures ranged from 160 to 200 °C. The ECS catalyst allowed the selective hydrolysis of Eucalyptus to glucose and xylose, as proved by high-performance liquid chromatography. The data herein are associated with the article entitled “ Unveiling one-pot fabrication of scalable and reusable carboxylated heterogeneous carbon-based catalyst from Eucalyptus plant with the assistance of dry Ice for selective hydrolysis of Eucalyptus Biomass’’ [1].


a b s t r a c t
The presented article reports the preparation and characterization of heterogeneous carbon catalyst enriched with carboxylic group denoted as (ECS) from Eucalyptus as an efficient catalyst for the hydrolysis of woody Eucalyptus biomass . The fabrication process is based on the ball milling of Eucalyptus as a carbon source in the presence of dry ice as an oxidizing agent followed by acidification with the assistance of hydrochloric acid. The data are including the schematic for the full synthesis steps and characterization tools in addition to the thermogravimetric analysis and proton nuclear magnetic resonance analysis for the ECS catalyst. Meanwhile, the catalytic performance of ECS catalyst towards the hydrolysis of Eucalyptus was measured under different temperatures ranged from 160 to 200 °C. The ECS catalyst allowed the selective hydrolysis of Eucalyptus to glucose and xylose, as proved by high-performance liquid chromatography. The data herein are associated with the article entitled " Unveiling one-pot fabrication of scalable and reusable carboxylated heterogeneous carbon-based catalyst from Eucalyptus plant with the assistance of dry Ice for selective hydrolysis of Eucalyptus Biomass'' [1] .
© 2020 The Author(s • The as-obtained catalyst can be easily recycled and reused after the hydrolysis process.
• The presented data are essential for the preparation of reusable heterogeneous catalyst from various plants.

Data description
The data presented in this article are related to the rational design of efficient and reusable ECS catalysts from Eucalyptus plant and its utilization for the hydrolysis of Eucalyptus plant [1] . The data including the detailed schematic of the experimental, characterization, and hydrolysis application apparatus, including ball-miller for the preparation of ECS catalyst from Eucalyptus , high-pressure rector for measuring the catalytic performance over Eucalyptus plant, and HPLC for determination the hydrolysis products as well as characterization tools ( Scheme 1 ). The photographs for showing the difference between the pristine Eucalyptus plant and the ECS catalyst ( Fig. 1 ). This is in addition to using the 1 H NMR for identifying the chemical structure of the as-obtained ECS catalysts compared to natural Eucalyptus plant ( Fig. 2 ) and the TGA to investigation the thermal stability of ECS catalysts obtained at different milling times including 24, 36, 45, and 64 h ( Fig. 3 ). Then, the hydrolysis products of Eucalyptus on the as-synthesized ECS catalyst carried out under different temperatures, including 160 ( Fig. 4 a), 180 ( Fig. 4 b) and 200 °C ( Fig. 4 a) as well as the hydrolysis products obtained during the reaction times ( Fig. 4 ).

Preparation process of ECS
Scheme S1 shows a schematic of the experimental and characterization apparatus for the formation of ECS catalyst from woody Eucalyptus biomass [ 1 , 2] . The preparation process, including mixing Eucalyptus and dry ice in a stainless-steel pot (250 ml) contains stainless-steel balls  (5 mm), and then milling at 550 rpm using Ball miller (Fritsch P-6 planetary) for 2 h, followed by filtration, washing, and finally drying under air. The content of the carboxylic (COOH) group inside ECS catalyst could be easily controlled by adjusting the milling time. The obtained ECS catalysts were confirmed using various characterization tools such as TGA for thermal stabilities and 1 H NMR for chemical structure [1 , 3 , 4] . The high-pressure reactor for the hydrolysis process and HPLC for the identification of the products. Fig. 1 shows the photographs of pure Eucalyptus and the obtained ECS, which indicates changing the color of pure Eucalyptus from the pale brown to deep black color after the carboxylation process and annealing (Fig. S1). Fig. 2 shows the 1 H NMR spectra for both ECS catalyst and pure Eucalyptus, which both showed the signals attributed to the H of the aliphatic carbons between 0.9 and 1.6 ppm in addition to the signals between 6.3 and 9.5 ppm [5][6][7] . Meanwhile, the ECS catalyst reveals the signal assigned to H bonded to the C = O group at 12.0 ppm, indicating the successful formation of ECS catalyst composed of C-aromatic skeletal enriched with COOH group and some aliphatic  moieties [5][6][7] . The 1 H NMR displayed the absence of undesired products, except the signal at 2.5 and 3.35 ppm originated from H of dimethyl sulfoxide solvent.
The thermal stability of the as-synthesized ECS catalyst prepared under different milling times, comprising 24, 36, 45, 64 h, were investigated by the TGA, as shown in Fig. 3 . There is no any kind of noticed significant changes among all prepared ECS catalysts [8] . Meanwhile, all ECS catalysts were thermally stable until 200 °C (Fig. S3). The major decompositions of ECS were achieved between 250 and 450 °C as the carbon-based catalysts are highly stable thermally and chemically [9] . Fig. 4 depicts the catalytic performance of ECS catalyst over Eucalyptus benchmarked at 160, 180, and 200 °C in the presence of 120 ppm of HCl, and the reaction products were estimated using the HPLC at 10 min intervals each. It should be noticed that, before any hydrolysis process, both Eucalyptus and ECS were milled together for 2 h to enhance the contact between them in line with elsewhere reports [10][11][12][13][14] . In particular, at 160 °C, the hydrolysis of Eucalyptus increased with time till achieving the maximum glucose yield of (70%) and xylose yield of (82%) after 1 h ( Fig. 4 a). Likewise, at 180 °C, the hydrolysis activity increased quickly until 17 min to reach the maximum production yield of (81%) for glucose and (95%) of xylose, followed by quickly decreasing until reaching the lowest yield of nearly (10%) for xylose and (15%) for glucose after 1 h ( Fig. 4 b). At 200 °C, the hydrolysis enhanced promptly to reach the maximum value of glucose (69%), and xylose (80%) after 10 min and then decreased quickly ( Fig. 4 c). Under all the temperatures used, only an inferior amount of furfural acid was detected. All data showed that the kinetics of hydrolysis at 200 °C was higher than that at 180 °C and 160 °C, respectively [15] . Meanwhile, the optimum reaction temperature was 180 °C.