Biomass Group, Nanjing Agricultural University, PO Box 68, 40 Dianjiangtai Road, Nanjing 210031

超顺磁酸碱双功能纳米ZrFeOx催化剂的合成及用以生产生物燃料

酸碱双功能纳米颗粒广泛用来合成生物燃料和高附加值的化学品。特别是磁性纳米金属氧化物，活性高可一锅法生产生物燃料，易于回收和重复利用。

生物能源组与贵州大学联合培养的博士生李虎在导师杨松教授和方真研究员的指导下，通过溶剂热处理和水解缩合的两步法合成酸碱双功能的超顺磁性纳米颗粒。合成的ZrFeOx纳米颗粒大约为12 nm, 中心为Fe₃O₄纳米颗粒(作为磁核)，其外面覆盖了一层0.65 nm厚的ZrO₂。ZrFeOx纳米颗粒具有分布良好的酸碱含量(0.39 vs. 0.28 mmol/g)，适度的表面积(181 m²/g)，孔径(9.8 nm)和较强的磁性(35.4 Am² kg⁻¹)。ZrFeOx纳米颗粒在乙醇中，进一步用来催化乙酰丙酸乙酯转换为γ戊内酯(GVL): 在230 ºC，反应3小时，GVL产率可高达87.2％。该纳米催化剂与固体酸HY2.6组合，可将糖直接转化为GVL，得到适中产率（约45％）。此外，磁性ZrFeOx纳米颗粒可很方便地由磁铁回收，可进行至少六次的重复利用。

祥情可见：

H Li, Zhen Fang*, S Yang, Direct Conversion of Sugars and Ethyl Levulinate into γ-Valerolactone with Superparamagnetic Acid-Base Bifunctional ZrFeOx Nanocatalysts, ACS Sustainable Chemistry & Engineering, 4(1), 236-246 (2016).
Synthesis of Superparamagnetic Acid−Base Bifunctional ZrFeOx Nanocatalyst for Biomass Conversion

Acid−base bifunctional nanocatalysts can directly on-pot produce biofuels and chemical from biomass. Particularly, some magnetic metal oxides that are active and recyclable.

Mr. Hu Li, a PhD student, co-supervised by Prof. Song Yang (Guizhou University) and Prof. Zhen FANG (Biomass Group, Xishuangbanna Tropical Botanical Garden, CAS) successfully synthesized bifunctional ZrFeOx nanocatalyst for biomass conversions.

In their work, acid-base bifunctional superparamagnetic FeZrO_x nanoparticles were synthesized via a two-step process of solvothermal treatment and hydrolysis-condensation, and were further employed to catalyze the conversion of ethyl levulinate (EL) to γ-valerolactone (GVL) using ethanol as both H-donor and solvent. ZrFeO(1:3)-300 nanoparticles (12.7 nm) with Fe₃O₄ core covered by ZrO₂ layer (0.65 nm thickness) having well- distributed acid-base sites (0.39 vs. 0.28 mmol/g), moderate surface area (181 m²/g), pore size (9.8 nm) and strong magnetism (35.4 Am² kg⁻¹) exhibited superior catalytic performance, giving a high GVL yield of 87.2% at 230 ºC in 3 h. The combination of the nanoparticles with solid acid HY2.6 promoted the direct transformation of sugars to produce GVL in moderate yield (around 45%). Moreover, the nanocatalyst was easily recovered by a magnet for six cycles with an average GVL yield of 83.9% from EL.

The study was published:

H Li, Zhen Fang*, S Yang, Direct Conversion of Sugars and Ethyl Levulinate into γ-Valerolactone with Superparamagnetic Acid-Base Bifunctional ZrFeOx Nanocatalysts, ACS Sustainable Chemistry & Engineering, 4(1), 236-246 (2016).

TEM images of ZrFeOx nanocatalyst

磁性镍锆纳米氧化物，高效催化生物质合成γ戊内酯（GVL）
γ戊内酯（GVL）已被确定为一种绿色的和可再生的溶剂，用以提高生物质转化和各种有机反应。它可作为液体燃料，香料和食物的添加剂。更重要的是，GVL可以用来合成汽油和柴油燃料（例如，C₈-C₁₈烷烃和2-甲基四氢呋喃）和高价值的化学物质（如1,4-戊二醇，甲基戊酸，离子液体和聚合物）。

生物能源组与贵州大学联合培养的博士生李虎在导师杨松教授和方真研究员的指导下，用共沉淀方法合成了一系列的混合氧化物纳米颗粒。研究发现，在不使用外部氢源的情况下，还原后的磁性镍 – 氧化锆纳米颗粒可直接高效转化生物质衍生物（如乙酰丙酸乙酯，果糖，葡萄糖，纤维二糖和羧甲基纤维素）为GVL。用磁性纳米颗粒Zr₅Ni₅（< 20纳米）作为催化剂，在200℃下反应3小时，最大GVL产率为95.2％。这些纳米催化剂具备酸碱二重性，对GVL的合成具有协同作用。 此外，磁性Zr₅Ni₅纳米颗粒可很方便地由磁铁回收，可进行至少五次的重复利用。

近日，文章“H Li, Zhen Fang*, S Yang, Direct Catalytic Transformation of Biomass Derivatives into Biofuel Component γ-Valerolactone with Magnetic NiZr Nanoparticles, 81, 135-142, (2016).” 在国际期刊《ChemPlusChem》发表:  http://onlinelibrary.wiley.com/doi/10.1002/cplu.201500492/abstract
Converting biomass derivatives into biofuel component γ-valerolactone (GVL) with magnetic NiZr nanoparticles

γ-valerolactone (GVL) has been identified as a green and renewable solvent to improve the performance of biomass conversion and various organic reactions, and as an additive suitable for liquid fuels, perfumes and food. More importantly, GVL is able to be employed as a precursor to produce gasoline and diesel fuels (e.g., C₈−C₁₈ alkanes and 2-methyltetrahydrofurane) and valuable chemicals such as 1,4-pentanediol and methyl pentenoate, as well as ionic liquids and polymers.

Mr. Hu Li, a PhD student, co-supervised by Prof. Song Yang (Guizhou University) and Prof. Zhen FANG (Biomass Group, Xishuangbanna Tropical Botanical Garden, CAS) successfully synthesized g-valerolactone.

In their work, a series of mixed oxide nanoparticles were prepared by coprecipitation method and characterized by many techniques. NiZr oxide catalysts and their partially reduced magnetic counterparts were highly efficient in direct transformation of biomass derivatives including ethyl levulinate, fructose, glucose, cellobiose and carboxymethyl cellulose into GVL without using external hydrogen source, producing a maximum GVL yield of 95.2% at 200 ºC for 3 h with H₂ reduced magnetic Zr₅Ni₅ nanoparticles (< 20 nm). Acid-base bifunctionality of these nanocatalysts is found to play a synergic role in synthesis of GVL in alcohols, while appropriate control of Ni/Zr molar ratio is able to improve the selectivity towards GVL (~98%), along with high formation rates (up to 54.9 mmol g⁻¹ h⁻¹). Moreover, the magnetic Zr₅Ni₅ nanoparticles were conveniently recovered by a magnet for five recycles with almost constant activity.

The study entitled “H Li, Zhen Fang*, S Yang, Direct Catalytic Transformation of Biomass Derivatives into Biofuel Component γ-Valerolactone with Magnetic NiZr Nanoparticles, 81, 135-142, (2016).” has been published in ChemPlusChem:  http://onlinelibrary.wiley.com/doi/10.1002/cplu.201500492/abstract

 Magnetic nanoparticles: Acid-base bifunctional NiZr nanocatalysts with strong magnetism show high activity and reusability in transformation of biomass derivatives including EL, fructose, glucose, cellobiose and carboxymethyl cellulose into γ-valerolactone (GVL) with 95.2% yield and 98% selectivity.

New US Patent Issued for ‘Fast Hydrolysis’ of Biomass without Adding Catalyst

 According to USPTO Public PAIR, a U.S. patent #: 9243303 has been issued to Zhen Fang (Kunming, CN) for technology that provides a simple and low-cost method to fast dissolve and hydrolyze lignocellulosic biomass with great potential for a novel biorefinery.

The patent entitled “Method for the dissolving and rapid hydrolyzing of lignocellulose biomass, device thereof and use of the same” was issued on Jan. 26, 2016 for work done by Professor Zhen Fang, Leader and Founder of Biomass Group at Chinese Academy of Sciences. Professor Fang stated, “I am very excited to have been granted this new U.S. patent containing such claims that provide protection for ‘fast hydrolysis’ process.

In previous work, It was found that by adding 0.8 wt% Na₂CO₃, actual wood without pretreatment can be completely dissolved upon fast-heating (7~16°C/s) to form a ‘wood solution’ at 329-367 ^oC at short reaction times (0.7-2 s). The ‘wood solution’ can be rapidly (ca. 15 s) hydrolyzed to sugars/sugar oligomers under homogeneous conditions.

Recently, Prof. Fang found that without adding any cayalyst, by putting lignocellulose biomass in pure water and rapidly heated to 330~403 ^oC, and then 89~99% of the lignocellulose biomass is dissolved and rapidly hydrolyzed to saccharide in 3.38~21.79 s. The following hydrolysis reaction can be carried out under the homogeneous phase condition for the dissolving of the lignocellulose biomass. At the same time, the solvated biomass could be easily used in the high pressure flow reactor to continuously pretreat the biomass and hydrolyze for producing saccharide, other biofuel and product. The present invention doesn’t need any catalyst and doesn’t pollute the environment, furthermore the process is simple and the cost is low, and it belongs to green and sustainable industry, and a good prospect of market application could be taken on.

The patent is the latest development in a 23-year effort by Professor Zhen Fang in the study of biomass hydrolysis process, aimed at a simple, fast and low-cost method for a novel biorefinery. ‘Fast hydrolysis’ process will be the technological key to economic utilization of abundant lignocellulosic biomass as viable feedstocks for the production of industrial sugar, ethanol and chemicals. His pioneering work opens the door, for the first time, to the possibility of developing industrial-scale technology at competitive cost for producing biofuels and value-added products from lignocellulosic biomass based on the ‘fast hydrolysis’ process in a flow reactor.

This patent is the third US patent issued to Professor Fang adding to its portfolio of 19 authorized Chinese patents that cover various features of biorefinery technologies after his returning to China in 2007.

非催化快速水解技术获美国专利

方真研究员发现，将木材或纤维素置于碱性或酸性溶液中，然后再将得到的混合物与高温水溶液混合，并以一定的加热速率加热至一定的高温，则可以实现木材或纤维素的完全溶解和快速水解。以该实验结果为基础，方真研究员发明的快速水解技术获得两项美国专利（US patent#: 9115215；8268126）。

最近，方真研究员在进一步地深入研究后发现：在高压热水中，不经任何预处理，不加任何催化剂，只需几秒钟时间，99%的木材可以快速溶解并水解。他设计并发明了一项装置，可连续、快速、大规模地水解木材，使得此项发现实现工业化生产成为可能。这一发现和发明，打破了常规催化（酸碱或酶催化）水解的方法和观念，为快速（几秒内）、绿色（不用任何催化剂）和省能（不用任何预处理）地水解木材，提供了一种全新的方法和思路。并将为生物质水解、生物冶炼为生物能源和化学品等下游产业提出一个新的研究方法。

该发明“Method for the dissolving and rapid hydrolyzing of lignocellulose biomass, device thereof and use of the same”获美国专利(US patent#: 9243303; issue date: 01/26/2016)。

这是方真研究员自2007年初回国后，在中国获得的第三个关于快速水解的美国专利。

“Fast dissolution of cellulose for hydrolysis” was authorized US patent
Recently, “fast dissolution of cellulose for hydrolysis” invented by Prof. Zhen Fang was authorized US patent (US patent#: 9115215; issue date: 08/25/2015).

In the nature, lignocellulosic biomass, such as wood and grass, is roughly consisted of 50% cellulose, 25% hemicellulose, and 20% lignin. Cellulose can be hydrolyzed into saccharides which are further used for producing cellulosic ethanol through fermentation. Because lignocellulosic biomass is water-insoluble, the current industrial methods for hydrolyzing biomass proceed mainly in a semi-continuous percolating reactor containing 0.4～0.8% dilute aqueous sulphuric acid, at temperature of 180～190℃ and under pressure of 12～14 atmospheres. Reports about continuous production of sugars in a high-pressure continuous flow reactor were not found.

Prof. Fang invented a method for completely dissolving and rapidly hydrolyzing cellulose, and uses thereof.

• Cellulose is placed in an acidic aqueous solution with a [H⁺] concentration of 10^-7～1 M or an alkaline aqueous solution with a [OH^–] concentration of 10^-7～1 M as sample A, wherein the volume ratio of solid to liquid is (0.003～05).
• The acidic aqueous solution with a [H⁺] concentration of 10^-7～1M or the alkaline aqueous solution with a [OH^–] concentration of 10^-7～1M is heated up to 261～352℃ as sample B.
• Sampe A and sample B obtained from step 1 and step 2 are mixed in a reactor to a concentration of cellulose of 0.1%～35%, the concentration of the mixed solution is adjusted to an acidity of 10^-7～1M [H⁺] or an alkalinity of 10^-7～1M [OH^–], and a water density of 587～997 kg/m³, pressure is set at 6～584 MPa. The mixture is rapidly heated up to 261～352℃ at heating rate of 7.8～8℃/s, and then cellulose is dissolved completely in 0.8～2 sec and hydrolyzed in 5 sec.

Using this technique, it is the first time for achieving complete dissolution and rapid hydrolysis of cellulose at a lower temperature, which not only dramatically reduces the cost of hydrolysis but also improves the safety of production and extends the service life of equipment in a flow system, thus possessing a good application prospect.
一种完全溶解和快速水解纤维素的方法及其应用获美国专利
自然界中的木质纤维素生物质如木材和草类，大约是由50%的纤维素，25%的半纤维素和20%的木质素组成。纤维素经水解能够降解为糖类，进而用于发酵生产纤维素酒精。由于木质纤维素生物质不溶于水，现有的工业化生物质水解方法主要是以半连续式渗透反应器、在180～190℃和12～14 大气压下的0.4～0.8%稀硫酸水溶液中水解。未见使用高压连续反应器进行连续生产的报道。

方真研究员在深入研究后发现，在溶解和快速水解纤维素之前，先将其置于酸性或碱性溶液中，然后再将得到的混合物与高温稀酸或稀碱溶液混合，并以一定的加热速率加热至一定的温度，则可以实现纤维素的完全溶解和快速水解。在此基础上，发明人提出如下技术方案：

一种完全溶解和快速水解纤维素的方法，包括以下步骤：

1、将纤维素置于浓度为10^-7～1M [H⁺]酸性或10^-7～1M [OH^–]碱性水溶液中，固液体积比为(0.003～1.05)：1；

2、将10^-7～1M[H⁺]酸性或10^-7～1M [OH^–]碱性水溶液加热至261～352℃；

3、混合步骤1和2所得物置于反应器中，纤维素浓度为0.1%～35%，调节混合后的物料溶液浓度为10^-7～1M [H⁺]酸性或10^-7～1M [OH^–]碱性，水密度为587～997 kg/m³，设定压力为6～584 MPa，加热速率为7.8～14.8℃/s，快速加热至261～352℃，0.8～2秒即能完全溶解纤维素。

溶剂化的纤维素可以很方便地应用于低温的高压流动式的反应器，进一步降低了生产成本，连续水解生产糖类及别的生物燃料和产品。

该发明获美国专利(US patent#: 9115215; issue date: 08/25/2015)。