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

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)。

Many biomass residues are produced in china and it is important to volatilize them, such as conversion of them to sugars by hydrolysis. The hydrolysis of lignocelluloses in concentrated and diluted homogenous acids has been practiced for many years, but problems such as corrosion hazards, acid-waste and difficulties in separation are not solved effectively. Various solid materials, such as transition metal oxides, ion-exchange resins, zeolites and sulfonated carbons are used as environmentally friendly catalysts for biomass hydrolysis because of their reusability, less corrosiveness and non-toxicity. And many magnetization methods are introduced by chemical reactions, such as precipitation and subsequent reduction of Fe³⁺ to Fe or Fe₃O₄ which may cause pollution and high cost. In this work, magnetic sulfonated acid was synthesized from glucose and magnetized without chemical reactions by simply mixing magnetic Fe₃O₄ nanoparticles with aqueous glucose solution.
Miss Tongchao Su (PhD student), under the guidance of Professor Zhen Fang from Xishuangbanna Tropical Botanical Garden (CAS), prepared magnetic catalyst (C-SO₃H/Fe₃O₄) by evaporation the mixture of Fe₃O₄ nanoparticles and aqueous glucose solution, and pyrolysis in a tubular furnace at temperature of 700 ^oC for 1 h, and sulfonated by 98% H₂SO₄ in oil bath at 150 ^oC for 20 h. The sulfonated sample was washed repeatedly with distilled water at 200 ^oC for 3 h until no SO₄^– was detected using CaCl₂. C-SO₃H/Fe₃O₄ catalyst had -SO₃H, -COOH and -OH acid groups for biomass hydrolysis. Under conditions of 9/50 cellulose/catalyst weight ratio, and 75/1 water/catalyst weight ratio for 3.5 h at 190 ^oC assisted with microwave, the catalyst was applied to the hydrolysis of bagasse, Jatropha and Plukenetia hulls. For water-ethanol extracted bagasse, Jatropha and Plukenetia hulls, higher yields of total reducing sugars (TRS), glucose and xylose were 79.8%, 58.3%, 97.2%; 47.2%, 35.6%, 96.4% and 54.4%, 35.8%, 94.9%, respectively. The catalyst had a good stability and after seven cycles, it showed no obvious deactivation.

The results are published in Scientific Reports:

TC Su, Zhen Fang*, F Zhang, J Luo, XK Li. Hydrolysis of Selected Tropical Plant Wastes Catalyzed by a Magnetic Carbonaceous Acid with Microwave, 5, 17538 (2015).

微波辅助碳基磁性固体酸水解热带植物废弃物

在中国, 随着经济的发展和人民生活水平的提高，产生出越来越多的生物质废弃物，应该充分利用它们，例如通过水解转化为可发酵糖以生产生物燃料和化学品。多年来，木质纤维素在液体酸中的水解得到广泛地研究和应用。但是设备腐蚀，酸废弃物以及回收问题都没有得到很好地解决。所以，近年来，多种固体催化剂被开发用以水解木质纤维素，例如过渡金属氧化物，离子交换树脂，沸石以及磺化碳等等。固体催化剂能够回收，无毒以及无腐蚀性等优点。通过化学方法沉淀，还原的方法引入磁性物质（Fe₃O₄）以便于催化剂更好地回收利用。本研究利用葡萄糖和纳米四氧化三铁为原料，通过简单的混合和磺化合成磁性酸催化剂。

中国科学院西双版纳热带植物园生物能源组，博士生苏同超小姐在方真研究员的指导下，通过蒸发四氧化三铁和葡萄糖混和溶液中的水分，然后在马弗炉中700 ^oC热解碳化1 h，以及在98%浓硫酸中磺化的方法成功合成了C-SO₃H/Fe₃O₄ 磁性催化剂。催化剂在使用之前，利用蒸馏水在200 ^oC水洗3 h直到水洗液中无SO₄^–基团。C-SO₃H/Fe₃O₄催化剂具有-SO₃H, -COOH和-OH酸性功能团，利于水解。在反应温度190 ^oC, 3.5 h, 9/50生物质和催化剂质量比，以及75/1水和催化剂质量比例条件下，在微波中水解甘蔗渣，小桐子果壳和南美油藤果壳。其中醇-水萃取之后的甘蔗渣，小桐子和南美油藤果壳材料，水解具有较高的产率，其中总还原糖、葡萄糖以及木糖的产率分别为79.8%, 58.3%, 97.2%; 47.2%, 35.6%, 96.4% 和54.4%, 35.8%, 94.9%。此催化剂具有很好地稳定性，催化剂利用七次之后仍无明显的失活。

相关研究成果发表在Scientific Reports上：
TC Su, Zhen Fang*, F Zhang, J Luo, XK Li. Hydrolysis of Selected Tropical Plant Wastes Catalyzed by a Magnetic Carbonaceous Acid with Microwave, 5, 17538 (2015).

                      图为磁性催化剂C-SO₃H/Fe₃O₄用于在微波水解热带植物废弃物

近日，方真研究员应 “生物燃料，生物制品和生物炼制”（他担任该刊顾问编委） 邀请，为该刊关于生物能源技术发展撰写社论。方真研究员建议设计并找到一种新的廉价和绿色的溶剂，在温和的条件下，溶解木质纤维素生物质，在均相的条件下进行生物炼制。

全球每年生物质生产量相当于8倍的世界能源消耗。大部分生物质是以木质纤维素的形式存在，含有75％的单糖（例如，木材和草：50％的纤维素和25％半纤维素）。问题的关键是如何释放这些丰富的生物聚合物成为水溶性糖，它们可很容易随后再转化为乙醇，脂类，其他生物燃料，各种化学品，食品和药品。

通常，有三种典型的方法水解木质纤维素为可发酵糖：（ⅰ）预处理后，在低温下酶解（例如，50摄氏度）；（ⅱ）在温和的温度下催化水解（例如，180摄氏度），和（iii）在高温近临界点下，快速水解（如350摄氏度）。溶解生物质以形成均相“生物质溶液”对于水解和预处理是非常重要的。溶解后的“生物质溶液”可像液态石油（而不是固体煤）一样，很容易加工，并可实际用于流动反应装置来提高生产效率。有机溶剂（例如，γ戊内酯，γ-valerolactone），离子液体和超临界流体均可以溶解生物质来水解。

生物质溶解后，这三种水解方法可以进一步改进以提高实际用途：（ⅰ）酶水解：酶，水和生物质分子可在一个均相条件下完全水解，不需要预处理步骤。然而，应考虑在工业生产中，如何回收酶，保持其较高的活性和降低成本。 （ii）催化水解：水解过程可用于流动反应装置以提高生产效率。与此同时，固体催化剂可替代液体酸，这样更绿色和环保。然而，固体催化剂的稳定性和活性需要进一步研究。 （iii）快速水解技术：尽管其效率高，但是，由于水解条件苛刻（如高温高压），工程问题（如反应器设计，材料和连续操作）等将成为障碍其商业化的关键。

1、Zhen Fang*, How Can We Best Solubilize Lignocellulosic Biomass for Hydrolysis? Biofuels Bioproducts and Biorefining, 9, 621–622 (2015) (invited editorial).

Solubilization of Lignocellulosic Biomass for Hydrolysis

By Jing-Mei Chen

Recently, Prof. Zhen Fang was invited to write an Editorial in “Biofuels, Bioproducts and Biorefining” (He is also serving as advisory editorial board member for this Journal). He suggested to design and find a green and inexpensive solvent to solubilize lignocellulosic biomass at mild conditions for novel biorefineries.

Annual global biomass production is equivalent to 8 times the world’s energy consumption. Most of biomass is in lignocellulosic form that contains 75% sugar units (e.g., wood and grass plants: 50% cellulose and 25% hemi-cellulose). The key is how to release these abundant biopolymers to become water-soluble sugars that are easily subsequently converted into ethanol, lipids, other bio-fuels, various chemicals, foods, and medicines. There are three typical methods to hydrolyze lignocelluloses to sugars.

Typically, the three ways are used for hydrolysis: (i) enzymatic hydrolysis after pretreatment at low temperatures (e.g., 50 ^oC), (ii) catalytic hydrolysis at mild temperatures (e.g., 180 ^oC), and (iii) fast hydrolysis at high temperatures near critical point (e.g., 350 ^oC). It is very important to solubilize biomass to form a homogenous phase for hydrolysis and pretreatment. The homogenous biomass solution (like petroleum not solid coal) is also easily processed in a flow system for practical applications. Organic solvents (e.g., γ-valerolactone), ionic liquids and supercritical fluids can dissolve actual biomass for hydrolysis.

After biomass solubilization, the three hydrolysis methods can be further improved for practical uses: (i) for enzymatic hydrolysis; enzymes, water and biomass molecules mix well in a homogenous phase for complete hydrolysis, pretreatment step is not required. However, how to recycle enzymes, keep high activity and reduce their cost should be considered for industrial production. (ii) For catalytic hydrolysis; a flow process can be built up to increase production efficiency. At the same time, solid catalysts may replace liquid acids for a green process. However, their stability and activity need study further. (iii) For fast hydrolysis; even though its high efficiency, however, owing to severe conditions (high temperature and pressure), engineering issues (such as reactor design, materials and continuous operation) become key obstacle to commercialize it.

1、Zhen Fang*, How Can We Best Solubilize Lignocellulosic Biomass for Hydrolysis? Biofuels Bioproducts and Biorefining, 9, 621–622 (2015) (invited editorial).

Cellulose completely dissolves in an ionic liquid for hydrolysis or pretreatment

纤维素完全溶解在离子液体中进行水解或预处理