1883-75-6Relevant articles and documents
Heteromacrocycles from Ring-Closing Metathesis of Unsaturated Furanic Ethers
Cottier, Louis,Descotes, Gerard,Soro, Yaya
, p. 4285 - 4295 (2003)
New 2,5-bix(unsaturated alkyloxymethyl)-furan led to macrocyclic furanic derivatives in the presence of Grubb's catalyst via dimerization or direct intramolecular metathesis according to the length of the sidearm.
Hydrogenolysis of 5-hydroxymethylfurfural to 2,5-dimethylfuran over supported Pt-Co bimetallic catalysts under mild conditions
Wang, Xiaofeng,Liu, Yuzi,Liang, Xinhua
, p. 2894 - 2902 (2018)
Highly dispersed Pt-Co bimetallic catalysts were deposited on multi-walled carbon nanotubes (MWCNTs) by atomic layer deposition. High-resolution TEM and TPR analyses verified the formation of Pt-Co bimetallic particles. Catalysts were applied for the hydrogenolysis of 5-hydroxymethyfurfural (HMF) to 2,5-dimethyfuran (DMF). A high yield of DMF (>90%) was achieved in the hydrogenolysis of HMF over the optimized Pt-Co/MWCNTs catalyst after 8 h of reaction time under 10 bar H2 at 160 °C. Through a series of experiments and comparison, the synergistic effect among Pt, Co, and MWCNTs was investigated. The results revealed that the synergistic effect between Pt-Co and MWCNTs played an important role in the improvement of selectivity to DMF for Pt-Co/MWCNTs bimetallic catalysts. In addition, steric hindrance appeared when Co loading in Pt-Co/MWCNTs was high and it affected the activity of the Pt-Co bimetallic catalysts. However, moderate activity can inhibit the production of byproducts and thereby improve the yield of DMF.
Bio-based furan polymers with self-healing ability
Zeng, Chao,Seino, Hidetake,Ren, Jie,Hatanaka, Kenichi,Yoshie, Naoko
, p. 1794 - 1802 (2013)
We report the preparation of a furan polymer, poly(2,5-furandimethylene succinate) by means of a condensation reaction between bio-based monomers. A reversible Diels-Alder reaction between furan and maleimide groups allowed the formation of network polymers cross-linked by a bismaleimide. By controlling the amount of the bismaleimide, mechanical properties were varied widely. These network polymers healed well when their broken surfaces were activated by bismaleimide solutions or solvent. The polymers also displayed excellent self-healing ability without external stimulus. This polymer class offers a wide range of possibilities to produce materials from biomass that have both practical mechanical properties and healing ability. These materials have the potential to bring great benefits to our daily lives by enhancing the safety, performance, and lifetime of products.
Direct Conversion of 5-Hydroxymethylfurfural to Furanic Diether by Copper-Loaded Hierarchically Structured ZSM-5 Catalyst in a Fixed-Bed Reactor
Hu, Hualei,Xue, Tingting,Zhang, Zhenxin,Gan, Jiang,Chen, Liangqi,Zhang, Jian,Qu, Fengzuo,Cai, Weijie,Wang, Lei
, p. 3461 - 3469 (2021)
The highly-efficient conversion of 5-hydroxymethylfurfural (HMF) to 2,5-bis(ethoxymethyl)furan (BEMF) was achieved over the copper-loaded hierarchically structured ZSM-5 (Cu/HSZ) catalysts in the continuous fixed-bed reactor. The main reaction path for BEMF synthesis on the Cu/HSZ catalysts was confirmed as following: HMF was firstly hydrogenated to BHMF intermediates over metal sites and then the formed BHMF was etherified by acid sites. Benefiting from the ammonia evaporation (AE) method promoted the dispersion of copper and reduced the acidity, the Cu/HSZ-AE catalyst exhibited more excellent BEMF yield and stability than the catalyst prepared by conventional incipient-wetness impregnation (Cu/HSZ-IW). Indeed, the inactivation of Cu/HSZ-IW catalyst was mainly attributed to the deactivation of copper by carbon species deposition.
Selective Conversion of 5-Hydroxymethylfuraldehyde Using Cp?Ir Catalysts in Aqueous Formate Buffer Solution
Wu, Wei-Peng,Xu, Yong-Jian,Zhu, Rui,Cui, Min-Shu,Li, Xing-Long,Deng, Jin,Fu, Yao
, p. 1209 - 1215 (2016)
The highly selective hydrogenation/hydrolytic ring-opening reaction of 5-hydroxymethylfuraldehyde (5-HMF) was catalyzed by homogeneous Cp?IrIII half-sandwich complexes to produce 1-hydroxy-2,5-hexanedione (HHD). Adjustment of pH was found to regulate the distribution of products and reaction selectivity, and full conversion of 5-HMF to HHD with 99 % selectivity was achieved at pH 2.5. A mechanistic study revealed that the hydrolysis/ring-opening reaction of 2,5-bis-(hydroxymethyl)furan is the important intermediate reaction step. In addition, an isolated yield of 85 % for HHD was obtained in a 10 g-scale experiment, and the reaction with fructose as the starting material also led to a 98 % GC yield (71.9 % to fructose) of HHD owing to the excellent tolerance of the catalyst under acidic conditions. pH dependent: A catalytic system is developed for the selective conversion of 5-hydroxymethylfuraldehyde to 1-hydroxy-2,5-hexanedione in high yield and selectivity. The Cp?IrIII half-sandwich catalysts have an excellent tolerance to acidic aqueous conditions and can transform 5-HMF in the hydrolysis solution of fructose in excellent yield, demonstrating a potential for a large-scale production.
Dynamic combinatorial libraries of 2,5-diformylfuran-derived macrocycles
Ziach, Krzysztof,Obrocka-Hrycyna, Aleksandra,Jurczak, Janusz
, p. 10334 - 10341 (2014)
A series of polyazamacrocycles, containing a furan moiety, have been prepared using the all-in-solution approach of dynamic combinatorial chemistry. The methodology involves the use of a range of simple, fully soluble inorganic salts as templates and fast imine-to-amine reduction followed by high-performance liquid chromatography screening for the best reaction conditions. It offers an elegant and labor-efficient alternative to the classical methodology of imine trapping via crystallization of complexes. For all the presented 2,5-diformylfuran-derived libraries, the templates provided control over the libraries behavior, which was reflected in increased isolated yields of the corresponding macrocyclic amines, compared to those of nontemplated libraries. The key parameters for achieving true thermodynamic control over the system, which are macrocyclization kinetics and imine reduction kinetics using NaBH4 accompanied by various protic additives, have been discussed.
Efficient and selective catalytic hydrogenation of furanic aldehydes using well defined Ru and Ir pincer complexes
Koranchalil, Sakhitha,Nielsen, Martin,Padilla, Rosa
, p. 6767 - 6772 (2020)
We report the homogeneous catalytic hydrogenation of biomass derived furanic aldehydes to furfuryl alcohols using low loadings of PNP metal complexes under mild conditions. Our strategy represents an efficient and selective approach to the direct hydrogenation of furan derivatives to promising platform chemicals. This journal is
An integrated process for the production of 2,5-dihydroxymethylfuran and its polymer from fructose
Upare, Pravin P.,Hwang, Young Kyu,Hwang, Dong Won
, p. 879 - 885 (2018)
We report for the first time an integrated process for the selective production of 2,5-dihydroxymethylfuran (DHMF) from fructose via a two-step reaction in 1-butanol (BuOH). Fructose was initially dehydrated to 5-hydroxymethylfurfural in >95% yield using Amberlyst-15, and the resulting solution was directly transformed into DHMF in >97% yield by liquid-phase hydrogenation over a Cu(50)-SiO2 nanocomposite. This nanocomposite catalyst was demonstrated to be highly stable, with no Cu leaching or catalyst deactivation observed. The obtained DHMF/BuOH mixture was then transformed successfully into poly(2,5-furandimethylene succinate) by reaction with succinic acid. Thus, from both environmental and industrial perspectives, this protocol is a novel and effective method for producing a biomass-derived polymer from fructose.
Air-Stable and Reusable Cobalt Phosphide Nanoalloy Catalyst for Selective Hydrogenation of Furfural Derivatives
Ishikawa, Hiroya,Sheng, Min,Nakata, Ayako,Nakajima, Kiyotaka,Yamazoe, Seiji,Yamasaki, Jun,Yamaguchi, Sho,Mizugaki, Tomoo,Mitsudome, Takato
, p. 750 - 757 (2021)
While metal phosphides have begun to attract attention as electrocatalysts, they remain underutilized in the field of liquid-phase molecular transformations. Herein, we describe a supported cobalt phosphide nanoalloy (nano-Co2P) that functions as a highly efficient, reusable heterogeneous catalyst for the selective hydrogenation of furfural derivatives. The carbonyl moieties of several furfural derivatives were selectively hydrogenated to produce the desired products in high yields. In contrast to conventional nonprecious metal catalysts, nano-Co2P uniquely exhibited air stability, which enabled easy and safe handling and precluded the need for H2 pretreatment. Infrared and density functional theory studies revealed that the highly efficient hydrogenation is due to the favorable activation of the carbonyl moiety of furfural derivatives through the backdonation to its π? orbital from the Co d-electrons.
Efficient Cu catalyst for 5-hydroxymethylfurfural hydrogenolysis by forming Cu-O-Si bonds
Fang, Zhen,Kong, Xiao,Li, Luping,Peng, Bo,Zhu, Yifeng,Zhu, Yulei
, p. 7323 - 7330 (2020)
Selective hydrogenolysis of C-O bonds of biomass derived precursors has been identified as a promising and essential way to produce fuel additives. Supported transition metals were explored to give efficient reactivity commonly based on a bifunctionality strategy. Here, we report that covalent bonding between SiO2 and Cu features a homologous bifunctional catalyst with metallic Cu and Lewis acidic Cu cations. The catalyst gave superior reactivity for the conversion of 5-hydroxymethylfurfural into 2,5-dimethylfuran. Lewis acidic cations had more predominant roles than metallic sites for C-O hydrogenolysis by stretching and dissociating C-O bonds, whereas they remained inactive for CC bonds. The results rationalize the valence-state-sensitive catalysis for chemistry involving C-O cleavage. The covalent metal-O-Si bonding provides an alternative for developing efficient catalysts since silicates with such a feature are versatile in nature.
Two-step one-pot reductive amination of furanic aldehydes using CuAlOx catalyst in a flow reactor
Bukhtiyarov, Valerii I.,Bukhtiyarova, Marina V.,Nuzhdin, Alexey L.
, (2020)
Aminomethylhydroxymethylfuran derivatives are well known compounds which are used in the pharmaceutical industry. Reductive amination of 5-hydroxymethylfurfural (HMF) derived from available non-edible lignocellulosic biomass is an attractive method for the synthesis of this class of compounds. In the present study, the synthesis of N-substituted 5-(hydroxymethyl)-2-furfuryl amines and 5-(acetoxymethyl)-2-furfuryl amines was performed by two-step process, which includes the condensation of furanic aldehydes (HMF and 5-acetoxymethylfurfural) with primary amines in methanol on the first step and the reduction of obtained imines with hydrogen in a flow reactor over CuAlOx catalyst derived from layered double hydroxide on the second step. This process does not require isolation and purification of intermediate imines and can be used to synthesize a number of aminomethylhydroxymethylfurans in good to excellent yield.
Superior catalytic performance of Ce1-xBixO2-δ solid solution and Au/Ce1-xBixO2-δ for 5-hydroxymethylfurfural conversion in alkaline aqueous solution
Miao, Zhenzhen,Zhang, Yibo,Pan, Xiqiang,Wu, Tianxiao,Zhang, Bin,Li, Jingwei,Yi, Ting,Zhang, Zhendong,Yang, Xiangguang
, p. 1314 - 1322 (2015)
Porous Bi-doped ceria (Ce1-xBixO2-δ solid solution) was prepared by the easy citrate method and then used as a supporting material for Au nanoparticles (NPs) obtained by deposition-precipitation. In the presence of O2, Ce1-xBixO2-δ (0.08 ≤ x ≤ 0.5) efficiently catalyzed the conversion of 5-hydroxymethylfurfural (HMF) to 5-hydroxymethyl-2-furancarboxylic acid (HFCA) and 2,5-bishydroxymethylfuran (BHMF) in alkaline aqueous solution without degradation of HMF. The excellent catalytic activity was attributed to the oxygen activation and hydride transfer enhanced by Bi doping and the large amount of oxygen vacancies. After Au NPs were supported on Ce1-xBixO2-δ (x ≤ 0.2), the presence of Auδ+ facilitated the activation of the C-H bond in the hydroxymethyl group and then the production of 2,5-furandicarboxylic acid (FDCA) as an end product, inhibiting the generation of BHMF.
Novel catalysts for valorization of biomass to value-added chemicals and fuels
Lucas, Nishita,Kanna, Narasimha Rao,Nagpure, Atul S.,Kokate, Ganesh,Chilukuri, Satyanarayana
, p. 403 - 413 (2014)
Key furan compounds such as 5-hydroxymethylfurfural (HMF), 2,5-furandicarboxylic acid (FDCA) and 2,5-dimethylfuran (DMF) were synthesized from renewable feedstocks. Dehydration of fructose was carried out in biphasic conditions employing several solid acid catalysts by targeting selective formation of HMF. Its selectivity is linearly dependent on total acidity clearly revealing that lower acidity favours selective formation of HMF. Oxidation and hydrogenolysis of HMF has been explored using 2 wt% Ru-K-OMS-2. The catalysts used for each transformation were subjected to detailed characterization using XRD, BET surface area, temperature-programmed desorption and transmission electron microscopy. The effect of various reaction parameters was also investigated for obtaining high yields of desired chemical intermediates. High FDCA yields of 93.4 mol% and 66 mol% were achieved in alkaline and base-free conditions, respectively. The 2 wt% Ru-K-OMS-2 is a versatile catalyst as it also catalyses HMF hydrogenolysis giving 33 mol% of DMF. Thus, utility of various novel materials as catalysts has been demonstrated in the multistep transformations of hexoses to furan-based fuels and chemicals.
A continuous flow strategy for the coupled transfer hydrogenation and etherification of 5-(hydroxymethyl)furfural using lewis acid zeolites
Lewis, Jennifer D.,Van De Vyver, Stijn,Crisci, Anthony J.,Gunther, William R.,Michaelis, Vladimir K.,Griffin, Robert G.,Roman-Leshkov, Yuriy
, p. 2255 - 2265 (2014)
Hf-, Zr- and Sn-Beta zeolites effectively catalyze the coupled transfer hydrogenation and etherification of 5-(hydroxymethyl)furfural with primary and secondary alcohols into 2,5-bis(alkoxymethyl)furans, thus making it possible to generate renewable fuel
Substrate and product role in the Shvo's catalyzed selective hydrogenation of the platform bio-based chemical 5-hydroxymethylfurfural
Pasini, Thomas,Solinas, Gavino,Zanotti, Valerio,Albonetti, Stefania,Cavani, Fabrizio,Vaccari, Angelo,Mazzanti, Andrea,Ranieri, Silvia,Mazzoni, Rita
, p. 10224 - 10234 (2014)
The bio-based substrate and target product 2,5-bishydroxymethylfuran (BHMF) demonstrated to influence the reaction kinetics in the homogeneous reduction of 5-hydroxymethylfurfural (HMF) catalyzed by the Ru-based Shvo's catalyst. A combined experimental an
Selective hydrogenation of 2-hydroxymethyl-5-furfural to 2,5-bis(hydroxymethyl)furan over gold sub-nano clusters
Ohyama, Junya,Esaki, Akihiko,Yamamoto, Yuta,Arai, Shigeo,Satsuma, Atsushi
, p. 1033 - 1036 (2013)
We report a gold sub-nano cluster supported on Al2O3 catalyzed hydrogenation of 2-hydroxymethyl-5-furfural without furan ring hydrogenation and its opening reaction, which resulted in excellent conversion to 2,5-bis(hydroxymethyl)furan (>96% yield), Fig. 1(a). The Royal Society of Chemistry 2013.
An integrated process for the production of 2,5-dimethylfuran from fructose
Upare, Pravin P.,Hwang, Dong Won,Hwang, Young Kyu,Lee, U-Hwang,Hong, Do-Young,Chang, Jong-San
, p. 3310 - 3313 (2015)
2,5-Dimethylfuran was successfully produced in 92% overall yield from fructose in 1-butanol through a combination of dehydration over Amberlyst-15 and hydrogenolysis over the Ru-Sn/ZnO catalyst. The environmental favorability of this process, and its unprecedented efficiency, makes it promising from both a green chemistry and an industrial perspective.
Gas phase hydrogenation of furaldehydes via coupling with alcohol dehydrogenation over ceria supported Au-Cu
Pischetola, Chiara,Collado, Laura,Keane, Mark A.,Cárdenas-Lizana, Fernando
, (2018)
We have investigated the synthesis and application of Au-Cu/CeO2 (Cu: Au = 2) in the continuous gas phase (P = 1 atm; T = 498 K) coupled hydrogenation of 5-hydroxymethyl-2-furaldehyde (HMF) with 2-butanol dehydrogenation. STEM-EDX analysis revealed a close surface proximity of both metals in Au-Cu/CeO2 post-TPR. XPS measurements suggest (support → metal) charge transfer to form Auδ? and strong metal-support interactions to generate Cu0 and Cu+. Au-Cu/CeO2 promoted the sole formation of 2,5-dihydroxymethylfuran (DHMF) and 2-butanone in the HMF/2-butanol coupling with full hydrogen utilisation. Under the same reaction conditions, Au/CeO2 was fully selective to DHMF in standard HMF hydrogenation (using an external hydrogen supply), but delivered a lower production rate and utilised less than 0.2% of the hydrogen supplied. Exclusive -C=O hydrogenation and -OH dehydrogenation is also demonstrated for the coupling of a series of m-substituted (-CH3, -CH2CH3, -CH2OH, -CF3, -N(CH3)2, -H) furaldehydes with alcohol (1-propanol, 1-butanol, 2-propanol, 2-butanol, cyclohexanol) dehydrogenation over Au-Cu/CeO2, consistent with a nucleophilic mechanism. In each case, we observed a greater hydrogenation rate and hydrogen utilisation efficiency with a 3–15 times lower E-factor in the coupling process relative to standard hydrogenation. Our results demonstrate the feasibility of using hydrogen generated in situ through alcohol dehydrogenation for the selective hydrogenation of m-furaldehydes with important industrial applications.
Selective mono-reduction of pyrrole-2,5 and 2,4-dicarboxylates
Yasui, Eiko,Tsuda, Jyunpei,Ohnuki, Satoshi,Nagumo, Shinji
, p. 1262 - 1267 (2016)
Pyrrole-2,5-dicarboxylates were rapidly and selectively reduced to the corresponding mono-alcohol using 3 eq of diisobutylaluminum hydride at 0°C. Pyrrole-2,4-dicarboxylate showed the same reactivity; however, the selectivity decreased with pyrrole-3,4-dicarboxylate. When the nitrogen atom of the pyrrole-2,5-dicarboxylate is protected with a benzyl group, selective mono-reduction does not occur. Considering that furan-2,5-dicarboxylates did not give the corresponding mono-alcohol under the same conditions, the unprotected nitrogen atom of pyrrole apparently plays an important role in this selective mono-reduction.
Production of dimethylfuran from hydroxymethylfurfural through catalytic transfer hydrogenation with ruthenium supported on carbon
Jae, Jungho,Zheng, Weiqing,Lobo, Raul F.,Vlachos, Dionisios G.
, p. 1158 - 1162 (2013)
RuCees' transfer: Transfer hydrogenation using alcohols as hydrogen donors and supported ruthenium catalysts results in the selective conversion of hydroxymethylfurfural to dimethylfuran (>80 % yield). During transfer hydrogenation, the hydrogen produced from alcohols is utilized in the hydrogenation of hydroxymethylfurfural. Copyright
Catalytic transfer hydrogenation of furfural into furfuryl alcohol over Ni–Fe-layered double hydroxide catalysts
Wang, Tao,Hu, Aiyun,Wang, Haijun,Xia, Yongmei
, p. 1610 - 1618 (2019)
Layered double hydroxides (LDHs) and their derivatives have been reported to be widely used as heterogeneous catalysts in various reactions. Herein, Ni-Fe LDHs with the controlled Ni/Fe molar ratios (2:1, 3:1, 4:1) were synthesized via an easy hydrothermal method, which were used to catalyze the selective reduction of biomass-derived furfural into furfuryl alcohol using 2-propanol as a H-donor under autogenous pressure and characterized using FT-IR, XRD, TGA, BET, SEM, NH3-TPD, and CO2-TPD. It was found that the LDH with a Ni/Fe molar ratio of 3:1 demonstrated the best catalytic activity among the LDHs with different Ni/Fe molar ratios, which showed 97.0% conversion of furfural and 90.2% yield of furfuryl alcohol at 140°C for 5 hr. This was attributable to the synergistic effect of acidic sites and basic sites of the catalyst.
Going Beyond the Limits of the Biorenewable Platform: Sodium Dithionite-Promoted Stabilization of 5-Hydroxymethylfurfural
Gomes, Rafael F. A.,Mitrev, Yavor N.,Simeonov, Svilen P.,Afonso, Carlos A. M.
, p. 1612 - 1616 (2018)
The lack of thermal and storage stability and occurrence of side reactions during the processing of 5-hydroxymethylfurfural (5-HMF) limits its potential as biorenewable platform molecule. The addition of small amounts of the readily available sodium dithionite has a remarkable effect on promoting the stability of 5-HMF and inhibiting side reactions, thus helping to circumvent such limitations. The addition of sodium dithionite led to improvements in thermal stability (120 °C, 4 h, neat; 100 % vs. 37 %), under distillation (yield: 85 % vs. 52 %), and in a wide range of reactions, including 5-HMF synthesis under biphasic conditions (yield: 98 % vs. 67 %; purity: 92 % vs. 83 %) and 5-HMF transformations, such as Knoevenagel condensation with Meldrum's acid (yield: 96 % vs. 74 %), Cannizaro reaction (yield: quantitative vs. 83 %), and condensation with primary diamines to give pyridinium salts (yield: 88 % vs. 60 %).
Whole-cell biocatalytic selective oxidation of 5-hydroxymethylfurfural to 5-hydroxymethyl-2-furancarboxylic acid
Zhang, Xue-Ying,Zong, Min-Hua,Li, Ning
, p. 4544 - 4551 (2017)
Currently, the catalytic upgradation of 5-hydroxymethylfurfural (HMF), an important bio-based platform chemical, is of great interest. In this work, we reported the biocatalytic oxidation of HMF to 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) by using a newly isolated strain Comamonas testosteroni SC1588. Compared to growing cells, resting cells were found to be a better biocatalyst for the synthesis of HMFCA. This strain exhibited high tolerance to HMF (up to 180 mM). However, its catalytic performances were highly sensitive to pH. The product exerted a significant negative effect on the catalytic performances and viability of the cells, partially due to the acidity of this compound. The product inhibition and toxicity toward this strain were reduced considerably after adjusting the pH of the reaction mixtures to 7.0. Excellent substrate conversions (approximately 100%) and good HMFCA yields (88-99%) were obtained when the substrate concentrations were less than 130 mM. In addition, the HMFCA synthesis could be improved significantly by the combination of histidine addition with pH tuning at higher substrate concentrations. Catalytic activities of the cells increased markedly when they were cultivated in the presence of a low concentration of furfural and furfuryl alcohol. HMFCA was afforded in a yield of approximately 98% after 36 h at a substrate concentration of up to 160 mM. Besides, this strain was capable of selectively transforming other furfurals to the target acids with good yields of 90-93%.
Reductive Amination, Hydrogenation and Hydrodeoxygenation of 5-Hydroxymethylfurfural using Silica-supported Cobalt- Nanoparticles
Chandrashekhar, Vishwas G.,Natte, Kishore,Alenad, Asma M.,Alshammari, Ahmad S.,Kreyenschulte, Carsten,Jagadeesh, Rajenahally V.
, (2021/11/30)
Efficient and selective conversion of renewable feedstocks to essential chemicals and fuels applying green and sustainable catalytic processes is of central importance and attracts scientific interest. Among different biomass-based feedstocks, 5-hydroxymethylfurfural (HMF) represents valuable platform compound widely used for the synthesis of valuable chemicals, fuels, and polymers. Here we report cobalt nanoparticles catalyzed reductive amination, hydrogenation and hydrodeoxygenation of HMF to produce furan based primary, secondary and tertiary amines including N-methylamines as well as 2,5-bis(hydroxymethyl)furan, (5-methylfuran-2-yl)methanol and selected N-, O-, and S-containing heterocycles. Key to success for this HMF valorization is the use of reusable silica supported cobalt-based nanoparticles, which have been prepared by the immobilization and pyrolysis of Co-terephthalic acid-piperazine MOF template on silica.
