Covalent triazine frameworks (CTFs) represent an exciting new type of porous organic material (POP), which have some unique characteristics, i.e., aromatic CN linkage (triazine unit) and the absence of any weak bonds. In particular, the strong aromatic covalent bonds endow CTFs with high chemical stability and rich nitrogen content, which bring great value for many practical applications and the interesting heteroatom effect (HAE). The unique properties make CTFs attractive for various applications, such as separation and storage of gases, energy storage, photocatalysis and heterogeneous catalysis. Based on the current status of research, CTFs can be classified into two categories, i.e., amorphous and crystalline CTFs. Since 2008, a series of synthetic strategies have been developed, i.e., an ionothermal trimerization strategy, a phosphorus pentoxide (P2O5) catalyzed method, amidine based polycondensation methods, a superacid catalyzed method and a Friedel–Crafts reaction method. The advent of these methodologies has prompted researchers to construct well-defined crystalline CTFs. This critical review systematically summarizes the development and challenges in the synthesis and potential applications of CTFs.

Covalent triazine frameworks: synthesis and applications

Cellulose, lignin and lignocellulose are important bioresources in the nature. Their effective and environmentally friendly utilization not only reduces dependence on fossil resources but also protects the environment. Recently, a class of novel eco-friendly solvents, ionic liquids, is employed to dissolve and process these bioresources. In this mini-review, we summarized the recent advances of processing and valorization of cellulose, lignin and lignocellulose in ionic liquids. It is expected that this up-to-date survey provides a comprehensive information of this field, and accelerates the development and utilization of the renewable plant biomass resources.

Processing and valorization of cellulose, lignin and lignocellulose using ionic liquids

The issues over increases in energy demand and environmental pollution attributed to excessive use of fossil fuel have been the driving forces of the exploration for eco-friendly resource. Lignocellulosic biomass consisting of carbohydrates and lignin can be a renewable feedstock for replacing fossil fuels in the future because it is a plentiful and carbon neutral material. Especially, lignin, cross-linked phenolic polymers, is a topic of interest owing to its abundant production from pulp/paper industries as well as lignocellulose based biorefinery. The large potential of platform chemicals and biofuels from lignin has opened up an extensive range of opportunities to develop thermal and catalytic conversion technology. Over a few decades, several lignin conversion processes including catalytic pyrolysis, catalytic depolymerization, and catalytic oxidation have been developed to improve target products yields and to suppress side reactions. More recently, lignin-first approaches which maintain carbohydrates intact by selective extraction of lignin as valuable phenolics from whole biomass has been suggested. This review introduces recent ten years progress on thermal and catalytic conversion technology in terms of process type, catalyst development, and target products. This review is expected to offer an influential information for future research into the thermal and catalytic conversion of lignin as well as lignocellulosic feedstock.

Recent progress in the thermal and catalytic conversion of lignin

Polymers are used in simple consumer items like carpets, furniture, glues, and clothing but are also used in advanced engineering, including materials used in the aerospace industry. Therefore, pol...

Catalytic Approaches to Monomers for Polymers Based on Renewables

Covalent triazine frameworks – a sustainable perspective

Covalent triazine framework catalytic oxidative cleavage of lignin models and organosolv lignin

The invention discloses a method for preparing methyl nitrite by catalyzing methanol to reduce dilute nitric acid. The method comprises the following steps: by taking methanol as a reducing agent, under the action of catalysis of a carbon-based catalyst, reducing dilute nitric acid into nitrous acid at 30-100 DEG C, and esterifying nitrous acid and methanol, thereby preparing methyl nitrite. A fixed bed is adopted as a reactor, and nitrogen is taken as a carrier gas. The method is high in dilute nitric acid conversion efficiency, the prepared methyl nitrite is a gas, and raw material separation can be easily achieved.

Method for preparing prepare methyl nitrite by catalyzing methanol to reduce dilute nitric acid

A method for preparing polyamine by direct ammoniation of a polyhydroxy compound is disclosed. By using a polyhydroxy compound, ammonia gas or liquefied ammonia as a raw material and using a carrier-loaded liquid-phase reduced transition metal as a catalyst, an ammoniation reaction of the polyhydroxy compound under mild conditions is realized. The catalyst has high selectivity of polyamine. The catalyst can be recovered and recycled.

Method for preparing polyamine by direct ammoniation of polyhydroxy compound

The invention discloses a method for producing dehydrated sugar alcohol through a knapsack reaction and rectification device. The method is characterized in that highly-pure dehydrated sugar alcohol is produced from C5-C6 sugar alcohol through the knapsack reaction and rectification device. The knapsack reaction and rectification device comprises a raw material preheater, a knapsack reactor and arectification tower, and the knapsack reactor is filled with a catalyst playing a role in reaction; and a high-efficiency structured packing or tray is arranged in the rectification tower and plays arole in rectification and separation. The method allows the highly-pure dehydrated sugar alcohol to be directly obtained through extracting the product from the middle part of a rectification section.The method has strong versatility, and is suitable for the dehydration reaction of the C5-C6 sugar alcohol to prepare the highly-pure dehydrated sugar alcohol. Compared with traditional dehydrated sugar alcohol preparation methods, the method allowing the reaction to be moved to the outside of the rectification tower in the invention has the advantages of simple flow, few byproducts, low runningcost, and light color and high purity of the product.

Du Wenqiang

Papers

Covalent triazine framework catalytic oxidative cleavage of lignin models and organosolv lignin

Method for preparing prepare methyl nitrite by catalyzing methanol to reduce dilute nitric acid

Method for preparing polyamine by direct ammoniation of polyhydroxy compound

Method for producing dehydrated sugar alcohol through knapsack reaction and rectification device

Self‐Assembled Nickel Nanoparticles Supported on Mesoporous Aluminum Oxide for Selective Hydrogenation of Isophorone