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This research examines the possibilities of regulating the structure of cellulose precursor fibers spun from solutions in N-methylmorpholine-N-oxide when replacing aqueous coagulation baths with thermodynamically softer alcohol baths at different temperatures. The fibers were spun by the dry jet&ndash, wet method in isobutanol coagulation baths with a temperature of 25 &deg, C and 70 &deg, C. The study of the phase state of the solvent&ndash, coagulant system using viscometry and point cloud methods revealed the temperature-concentration regions of the single-phase and two-phase states of the system. Using elemental analysis, DSC (differential scanning calorimetry) and XRD (X-ray diffraction) methods, it was shown that just spun fibers, due to the presence of a residual amount of solvent and coagulant in them, regardless of the temperature of the precipitator, have an amorphous structure. Additional washing with water completely washed away the solvent and coagulant as well, however, the structure of cellulose changes slightly, turning into a defective amorphous-crystalline one. A relationship was found between the phase composition, structure, and properties of just spun fibers and precursors washed with water. Thus, the loss of structural ordering of both just spun and washed cellulose fibers leads to a decrease in strength characteristics and an increase in deformation. The thermal behavior of the fibers is determined by their phase composition. Fibers just spun into hot alcohol containing a coagulant and traces of solvent acquire thermal stability up to 330 &deg, C. During the pyrolysis of the obtained precursors up to 1000 &deg, C, the value of the carbon yield doubles. The amorphized structure of the obtained fibers allows us to consider it as a model when analyzing the transformation of the structure of precursors during thermolysis.

Composite fibers and films based on cellulose and betulin were spun for the first time from solutions in N-methylmorpholine-N-oxide using the dry–wet jet method. The rheological properties of the composite solutions did not reveal any fundamental difference from those of the cellulose solutions. Introduction of betulin into the cellulose matrix (up to 10%) led to a decrease in the mechanical properties of the obtained fibers. The structure of the composite fibers was analyzed using SEM and X-ray diffraction methods. It was shown that the introduction of an additive into the cellulose matrix led to a decrease in the structural ordering of the cellulose. Comparative studies of the antibacterial activity of the composite films on Escherichia coli (E. coli) were carried out. The antifungal activity of the composite films was estimated using the strain of the O-97 Trichoderma viride Pers ex Fr (Gause Institute of New Antibiotics, Moscow, Russia).

In this study, the surface layer of cotton fabric was swelled with N-methylmorpholine-N-oxide with 18 % water content, washed and dried to improve its stiffness property. Finally, the finished fabric had no auxiliaries and self-stiffened. The results showed that the bending rigidity increased from 0.75 × 105 to 1.57 × 105 mN cm, the acute elastic crease recovery angle from 95.2° to 117.3°, the delayed elastic crease recovery angle from 117.6° to 146.6° and the moisture regain from 8.07 to 10.3 %. The stiffness was almost unaffected by 30 multiple washing times. The tear strength, breaking strength and whiteness properties remained excellent. Scanning electron microscopy showed that the edges of finished fibres obviously curled. According to infrared spectrum analysis, no new groups were found. X-ray diffraction analysis showed that the crystal structure of the fibre changed, with cellulose II formed disorderly in the surface layer of the cotton fibres. This mechanism permits the cotton fabric to self-stiffen in the modifying process.

Ethylamine hydroxyethyl chitosan (EHC), a novel chitosan derivative which is soluble in aqueous N-methylmorpholine-N-oxide (NMMO) and antibacterial to Escherichia coli (E. coli) was synthesized. The structure, solubility and antibacterial capability of EHC were investigated. Results demonstrated the potential application for EHC in manufacture of antibacterial EHC/cellulose Lyocell fiber. Through environment-friendly Lyocell process in aqueous NMMO, the EHC/cellulose fiber was successfully fabricated and the various properties of EHC/cellulose fiber were studied. Results showed the EHC/cellulose fiber exhibited favorable consistency, antibacterial activity, mechanical properties and water retention compared with the fiber without EHC.

A carbonized cellulose/single-walled carbon nanotube composite film (cell/SWCNTcarbon) was prepared with well-dispersed cellulose/SWCNT doped in N-methylmorpholine N-oxide (NMMO) monohydrate. After carbonization at 400 °C, the SWCNT content at electrical threshold of the cell/SWCNTcarbon nanocomposite decreased from 2 wt% to 1 wt%, and the electrical conductivity of the cell/SWCNT(1 wt%)carbon nanocomposite (0.6 S cm−1) increased by more than 6 orders of magnitude compared to that of pure carbonized cellulose (1.1 × 10−7 S cm−1). Further, it continuously increased as the carbonization temperature increased and reached 100 S cm−1 when the cell/SWCNT(1 wt%) nanocomposite was carbonized at 1400 °C. This drastic increase in the electrical conductivity at low carbonization temperatures (e.g. 400 °C) was due to the percolation of small carbon clusters with conducting SWCNTs. The incorporated SWCNTs improved flexibility and mechanical stability during carbonization so that the cell/SWCNT(1 wt%)carbon nanocomposite could be bent even after carbonization at 1400 °C; however, the carbonized cellulose prepared using the same method was too brittle. This cell/SWCNTcarbon nanocomposite may render the eco-friendly production of flexible electrodes for various applications, including heat sink parts, electromagnetic interference shielding materials, and electronic devices, feasible.

Solid-state powders of water-dispersible graphene (GPN) were prepared by treatment of methylmorpholine N-oxide monohydrate (NMMOm). Re-dispersion of GPN in water by simple sonication was successfully demonstrated using a highly concentrated aqueous GPN solution (0.284 mg mL−1) after centrifugation at 9000 rpm for 10 min. The produced GPN had the graphitic structure without defects, and its electrical conductivity was 94.7 S cm−1, as measured from a filtered GPN film. The spin-coated thin film from the aqueous GPN solution exhibited a single-layered structure, which was examined using scanning electron microscopy, atomic force microscopy, and scanning transmission electron microscopy (with selective area electron diffraction). The GPN was also dispersible in polar solvents such as dimethyl sulfoxide, dimethylformamide, ethanol, and tetrahydrofuran. The origin of good dispersity of GPN in polar solvents, including water, was discussed with reference to the high polar nature of NMMO. A nanocomposite system with a water-soluble poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was prepared on a glass substrate. A fourfold improvement in the electrical conductivity of PEDOT:PSS without deterioration of transmittance was achieved by adding 1 wt% GPN.

Lignocelluloses (LCs) with various amounts of lignin (even as high as 18.4%) were successfully dissolved in N-methylmorpholine-N-oxide monohydrate (NMMO/H2O) solution with stirring at 85 °C within 5 h. For the developmental dissolution methods of LCs with a high lignin content in NMMO/H2O solution, the following two pretreatment steps of LCs were necessary: (1) glycerol swelling and (2) mechanical extrusion. The mechanical extrusion pretreatment under glycerol swelling dissociated the fiber bundles of LCs to thinner fibers and, thus, enhanced the accessibility and solubility of the LCs in NMMO/H2O. The crystal structure of the pretreated LCs had no significant transformation during pretreatment, while the diameters of the fiber bundles were reduced from 50–60 to 10–12 μm, as investigated by X-ray diffraction and scanning electron microscopy. After the dissolution–regeneration process of LCs, the fiber bundles of the LCs disappeared and the crystal type of cellulose in the LCs was transformed from cellulos...

Chicken feather, a potential source of keratin, is often disposed as waste material. Although some methods, i.e., hydrolysis, reduction, and oxidation, have been developed to isolate keratin for composites, it has been limited due to the rising environmental concerns. In this work, a green solvent N-methylmorpholine N-oxide (NMMO) was used to extract keratin from chicken feather waste. Eighty-nine percent of keratin was extracted using 75% NMMO solution. However, the result from size exclusion HPLC showed that most of the keratin degraded into polypeptide with molecular weight of 2189 and only 25.3% regenerated keratin was obtained with molecular weight of 14,485. Analysis of amino acid composition showed a severe damage to the disulfide bonds in keratin during the extraction procedure. Oxidization had an important effect on the reconstitution of the disulfide bonds, which formed a stable three-dimensional net structure in the regenerated keratins. Besides, Raman spectra, NMR, FT-IR, XRD, and TGA were used to characterize the properties of regenerated keratin and raw chicken feather. In the end, a possible mechanism was proposed based on the results.

A series of O-carboxymethyl chitosan sodium salt (NaCMCh) with different degree of substitution (DS) of -CH2COONa agent were successfully prepared by altering the reaction temperature and time. Both fourier transform infrared spectroscopy (FTIR) and 13C-Nuclear Magnetic Resonance (13C-NMR) were used to study the structure of NaCMCh. And the impact of DS on the antibacterial activity of NaCMCh was investigated. Then, the NaCMCh with optimal antibacterial activity was selected to prepare NaCMCh/cellulose fibers in N-methylmorpholine-N-oxide (NMMO) system. The structure, crystallization behavior, thermal property and morphology of obtained fibers were carefully studied with FTIR, Wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), thermal gravimetric (TG) and scanning electron microscope (SEM), respectively. Meanwhile, the antibacterial activity as well as mechanical properties of resultant fibers was also investigated. The results demonstrated that the fibers had strong antibacterial activity against Escherichia coli (E. coli), acceptable mechanical properties and good water retention.

The effects of N-methylmorpholine-N-oxide (NMMO) pretreatment on barley straw and forest residues were investigated for biogas production. The pretreatments were performed at 90 degrees C with 85% NMMO for 3-30 h. The best pretreatment conditions resulted in 100% improvement in methane yield during the subsequent digestion compared to that of the untreated lignocelluloses. Methane yields of 0.23 and 0.15 Nm(3) CH4/kg VS were obtained from barley straw and forest residues, respectively, corresponding to 88% and 83% of the theoretical yields. In addition, the effects of the pretreatment with recovered and reused NMMO was also studied over the course of five cycles. Pretreatment with recycled NMMO showed the same performance as the fresh NMMO on barley straw. However, pretreatment of forest residues with recycled NMMO resulted in 55% reduction in methane yield.

The reactions of 1-benzyl-4-((phenylthio/phenylseleno)methyl)-1H-1,2,3-triazole (L1/L2) and 4-phenyl-1-((phenylthio/phenylseleno)methyl)-1H-1,2,3-triazole (L3/L4), synthesized using the click reaction, with [(η5-Cp*)RhCl(μ-Cl)]2 and [(η5-Cp*)IrCl(μ-Cl)]2 at room temperature followed by treatment with NH4PF6 result in complexes of the type [[(η5-Cp*)M(L)Cl] (1–8). Their HR-MS and 1H, 13C{1H}, and 77Se{1H} NMR spectra have been found characteristic. The single-crystal structures of 2, 3, and 6 have been established by X-ray crystallography. There is a pseudo-octahedral “piano-stool” disposition of donor atoms around Rh/Ir. In 1, 2, 5, and 6 N(3) of the triazole skeleton coordinates with Rh/Ir, whereas in the other four complexes the nitrogen involved is N(2). These complexes have been explored as catalysts for N-methylmorpholine N-oxide (NMO) based and Oppenauer-type oxidation of alcohols and transfer hydrogenation (TH) of carbonyl compounds with 2-propanol. Oppenauer type oxidation is somewhat slower than ...

Dichlorocarbene generated from chloroform in aqueous–alkaline medium in the presence of N-methylmorpholine N-oxide is converted to phosgene which reacts in situ with secondary amines to afford tetrasubstituted ureas.

Comparative studies of the structure and thermal behavior of cellulose and composite precursors with additives of silyl-substituted acetylene and alkoxysilanes were carried out. It is shown that the introduction of silicon-containing additives into the cellulose matrix influenced the thermal behavior of the composite fibers and the carbon yield after carbonization. Comparison of the activation energies of the thermal decomposition reaction renders it possible to determine the type of additive and its concentration, which reduces the energy necessary for pyrolysis. It is shown that the C/O ratio in the additive and the presence of the Si&ndash, C bond affected the activation energy and the temperature of the beginning and the end of the pyrolysis reaction.

Lignocellulosic biomass represents a great potential for biogas production. However, a suitable pretreatment is needed to improve their digestibility. This study investigates the effects of an organic solvent, N-Methylmorpholine-N-oxide (NMMO) at temperatures of 120 and 90 °C, NMMO concentrations of 75 and 85 % and treatment times of 3 and 15 h on the methane yield. The long-term effects of the treatment were determined by a semicontinuous experiment. The best results were obtained using 75 % NMMO at 120 °C for 15 h, resulting in 141 % increase in the methane production. These conditions led to a decrease by 9 % and an increase by 8 % in the lignin and in the carbohydrate content, respectively. During the continuous digestion experiments, a specific biogas production rate of 92 NmL/gVS/day was achieved while the corresponding rate from the untreated sample was 53 NmL/gVS/day. The operation conditions were set at 4.4 gVS/L/day organic loading rate (OLR) and hydraulic retention time (HRT) of 20 days in both cases. NMMO pretreatment has substantially improved the digestibility of forest residues. The present study shows the possibilities of this pretreatment method; however, an economic and technical assessment of its industrial use needs to be performed in the future.

Based on the enrichment culture strategy, a novel N-methylmorpholine-N-oxide (NMMO)-tolerant cellulase-producing strain Galactomyces sp. CCZU11-1 was isolated from soil samples. After the optimization of culture condition, the highest FPA (13.4 U/mL) and CMCase (24.5 U/mL) were obtained. In both culture and reaction media containing NMMO 25% (w/v), the cellulase from Galactomyces sp. CCZU11-1 still had good activity. Furthermore, high saccharification rate was obtained in aqueous-NMMO media. Moreover, the fermentability of the hydrolyzates, obtained after enzymatic in situ saccharification of the NMMO-pretreated sugarcane bagasse, was evaluated using Saccharomyce scerevisiae. In conclusion, Galactomyces sp. CCZU11-1 is a promising candidate as high NMMO-tolerant cellulase producer and has potential application in future.

A simple and rapid method for the conversion of organic halides into carbonyl derivatives is developed via microwave-assisted oxidation with N -methylmorpholine N-oxide in an ionic liquid. A variety of halide substrates are oxidized to the corresponding products in good to excellent yields in short reaction times. The ionic liquid is recovered and reused in several reaction cycles without any significant loss in activity.

The structure and rheological behavior of cellulose solutions in the high-polarity donor solvent N-methylmorpholine-N-oxide containing particles of layered aluminosilicates of various natures, namely, natural hydrophilic montmorillonite (Cloisite Na+) and hydrophobized montmorillonite (Cloisite 20A), are studied. The rheological properties of the mixed systems cellulose-N-methylmorpholine-N-oxide-Cloisite Na+ and cellulose-N-methylmorpholine-N-oxide-Cloisite 20A are similar, although their structures are different. This similarity may be explained by the fact that the highly developed structure of the cellulose matrix phase resulting from strong interactions between polar components of the system exerts the decisive effect on the character of flow of mixed solutions. Therefore, the filler assumes the minor role. The concentration dependences of solution viscosity turn out to be atypical when the content of moisture in Cloisite 20A is increased above the equilibrium value and when M2Cloisite Na+ nanoparticles modified in a certain manner are introduced into cellulose solutions.

Birch wood was pretreated with N-methylmorpholine-N-oxide (NMMO or NMO) followed by enzymatic hydrolysis and fermentation to ethanol or digestion to biogas. The pretreatments were carried out with NMMO ( w NMMO = 85%) at 130 °C for 3 h, and the effects of drying after the pretreatment were investigated. Enzymatic hydrolysis of the untreated wood resulted in 8%–10% of theoretical glucose yield after 4 days hydrolysis, while the NMMO pretreatment improved this yield to 91%. Consequently, ethanol production yield from NMMO-pretreated materials resulted in around 9-fold improvement compared to the untreated wood. On the other hand, drying of the pretreated wood had a negative impact and decreased the yield of enzymatic hydrolysis by 4%–10%. Digestion of the untreated wood with thermophilic bacteria resulted in maximum methane yield of 158 cm 3 g −1 of VS in 30 days, while the NMMO pretreatment improved the methane yield up to 232 cm 3 g −1 of VS (80% of the theoretical biogas yield) in just 9 days.

N-methylmorpholine N-oxide and silver oxide (Ag2O) oxidized four component reaction for the preparation of pyranopyrazole with different substituted pattern have been developed which provides rapid access to a library of compounds in good to excellent yields by using benzyl halide, malanonitrile/ethyl cyanoacetate, diethylacetylenedicarboxylate/ethyl acetoacetate and hydrazine hydrate as reactants. This transformation involves the breaking of one C‒O bond and formation of 2 C–C, 2 C–N, and a C‒O bond leading to the formation of a five and six membered ring in one pot operation.

Pretreatment of OPEFB (oil palm empty fruit bunch) by NMMO (N-methylmorpholine-N-oxide) on its subsequent digestions was investigated. The pretreatments were carried out at 90 and 120 degrees C for 1, 3, and 5 h in three different modes of dissolution (by 85% NMMO solution), ballooning (79% NMMO solution), and swelling (73% NMMO solution). The total solid recovery after the pretreatment was 89-94%. The pretreatment process did not have a major impact on the composition of OPEFB, other than a reduction of ash from 5.4% up to 1.3%. The best improvement in biogas production was achieved by a dissolution mode pretreatment of OPEFB, using conditions of 85% NMMO, 3 h, and 120 degrees C. It resulted in 0.408 Nm(3)/kg VS methane yield and 0.032 Nm(3) CH4/kg VS/day initial methane production rate, which correspond in improving by 48% and 167% compared to the untreated OPEFB, respectively.

A combinative technology of alkali and N-methylmorpholine-N-oxide (NMMO) was used to pretreat corn stalk (CS) for improving the efficiencies of subsequent enzymatic hydrolysis and ethanol fermentation. The results showed that this strategy could not only remove hemicellulose and lignin but also decrease the crystallinity of cellulose. About 98.0% of enzymatic hydrolysis yield was obtained from the pretreated CS as compared with 46.9% from the untreated sample. The yield for corresponding ethanol yield was 64.6% while untreated CS was only 18.8%. Besides, xylose yield obtained from the untreated CS was only 11.1%, while this value was 93.8% for alkali with NMMO pretreated sample. These results suggest that a combination of alkali with 50% (wt/wt) NMMO solution may be a promising alternative for pretreatment of lignocellulose, which can increase the productions of subsequent enzymatic hydrolysis and ethanol fermentation.

To fully exploit the benefits of N-methylmorpholine-N-oxide (NMMO) in lignocelluloses bioconversion, a compatible system was established for efficient in situ saccharification of cellulose in NMMO-aqueous media in which the NMMO is able to activate and solubilize the cellulose, and the cellulases possess high stability and activity. Cellulase retained its original activity after being pre-incubated in 15% and 20% (w/v) NMMO solutions. After optimization of reaction parameters, high saccharification rate (96.5%) was obtained in aqueous-NMMO media by ultrasound assisted treatment of cellulose. The viscosity and FTIR analysis revealed that NMMO-treated cellulose under ultrasonic condition was porous and amorphous, which led to improved saccharification. The addition of trifle lignin in lower concentration improved the saccharification efficiency of sugarcane bagasse, while higher concentration interferes with hydrolysis. In conclusion, these findings provided great implications to develop a continuous process NMMO-cellulases system for transformation of native biomass.

Highly concentrated solutions of cellulose and solutions of cellulose blends with synthetic polymers are prepared via the solid-phase dissolution of cellulose in N-methylmorpholine-N-oxide. The phase state and morphological features of these solutions are studied via DSC and polarization microscopy, and their rheological behavior is considered. Evolution in the structure of cellulose in these systems is investigated at all stages during spinning of oriented fibers from solutions. It is first shown that the addition of synthetic polymers to cellulose makes it possible to control processes of cellulose structuring; to stop them at the stage of mesophase formation; and, thus, to avoid further perfection of the structure and formation of the crystalline phase of cellulose.

International audience; The swelling and dissolution mechanisms of dry, never-dried and re-wetted Lyocell fibers were investigated using mixtures of N-methylmorpholine N-oxide and water with various contents of water (from monohydrate to 24% w/w). A radial dissolution starting from the outer layers was observed. Dissolution kinetics was dependent on the water content, the drying state and the spinning conditions. A buckling of the core of dry fibers was observed during swelling. This phenomenon was attributed to the deformation of the unswollen core to accommodate the contraction of the swollen parts of the fiber. In purely swelling conditions with no dissolution, a huge swelling of a very thin skin layer was observed in the first stage, followed then by a progressive swelling of the inside of the fiber. We postulate that this mechanism arose from the fact that this skin is much less crystalline than the core.

Sugarcane bagasse, a cheap cellulosic waste material, was investigated as a raw material for producing lyocell fibers at a reduced cost. In this study, bagasse was dissolved in N-methylmorpholine-N-oxide (NMMO) 0.9 hydrate, and fibers were prepared by the dry jet-wet spinning method with coagulation in an aqueous NMMO solution. The effects of NMMO in 0 to 50% concentrations on the physical properties of fibers were investigated. The coagulating bath contained water/NMMO (10%) solution produced fiber with the highest drawability and highest physical properties. The cross-section morphology of these fibers reveals fibrillation due to the high degree of crystallinity and high molecular orientation. In the higher NMMO concentrated baths (30 to 50%), the prepared fibers were hollow inside, which could be useful to make highly absorbent materials. The lyocell fibers prepared from bagasse have a tensile strength of 510 MPa, initial modulus of 30 GPa, and dynamic modulus of approximately 41 GPa. These properties are very comparable with those of commercial lyocell fibers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Pretreatment of softwood spruce and hardwood oak with an industrial cellulose solvent, N-methylmorpholine-N-oxide (NMMO), was investigated prior to enzymatic hydrolysis and fermentation to ethanol. The pretreatments were carried out at 90, 110 and 130 degrees C for 1-3 h with 85% NMMO solution, followed by non-isothermal simultaneous saccharification and fermentation (NSSF). This NSSF included hydrolysis with cellulase and beta-glucosidase for 24 h at 45 degrees C, followed by continuous saccharification and fermentation with Saccharomyces cerevisiae at 37 degrees C for 3 days. The NSSF of untreated oak and spruce resulted in 18.6% and 6.8% ethanol compared to the maximum theoretical yield. However, the pretreatment of oak and spruce at 130 degrees C resulted in almost total conversion of cellulose to ethanol and improved ethanol yield up to 85.4% and 89%, respectively. These numbers are comparable with ethanol from pure glucose with the same strain, which yielded between 84% and 90% of the theoretical ethanol yield.

To improve the dyeing properties of ramie, the ecofriendly organic solvent N-methylmorpholine-N-oxide (NMMO) was used to substitute sodium hydroxide as a ramie-fiber swelling solvent. Through padding and baking pretreatment, ramie fabric was modified by an NMMO aqueous solution. Ultraviolet–visible spectrophotometry, Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry were used to investigate the effects of NMMO pretreatment on the structure of the ramie, whereas the color strength (K/S, where K is the light absorption coefficient and S is the scattering coefficient), adsorption isotherm, and dye uptake rate curve were measured to investigate the effects of NMMO pretreatment on the dyeing properties of the ramie. The results show that the ramie fiber experienced a limited and irreversible swelling because of the partial breakage of interhydrogen and intrahydrogen bonds of cellulose molecules in the amorphous area, but the crystal and chemical structure of the ramie fiber did not change obviously under the experimental conditions. The K/S value of the NMMO-modified ramie fabrics dyed with reactive dyes increased by about 100%, and the dye uptake increased by 27.88% compared to that of the raw sample, whereas the standard affinity and diffusion coefficient value of the reactive dyes on the NMMO-modified ramie fabric were higher than those of the raw ramie fabric. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

A novel cellulose membrane used for isopropanol (IPA) dehydration was prepared by using N-methylmorpholine-N-oxide monohydrate (NMMO·H 2 O) as the solvent that can dissolve cellulose through a purely physical process. Scanning electron microscopy (SEM) images show that the prepared membrane had a homogeneously dense structure after natural drying. X-ray diffraction (XRD) and mechanical properties characterizations show that the prepared cellulose membrane owned much higher crystallization degree and better mechanical strength compared with traditional cellulose acetate (CA) or cellophane membranes coming from chemical process. The effects of operation conditions including feed concentration and operation temperature on pervaporation (PV) performance were investigated systemically. The results indicate that the permeation flux increased obviously with the increase of either water concentration in feed or operation temperature. Under the condition of 20 wt.% water-containing IPA feed and at 65 °C, a highest total flux of 349 g/m 2 h was achieved with a lowest water content in permeate of 99.50 wt.% (with a separation factor of 972) among all the tested conditions. Water content in permeate reached 99.97 wt.% (with a separation factor of 61,271) with a total flux of 13.4 g/m 2 h at the condition of 5 wt.% water in feed at 25 °C. Compared with other pure polymer membranes such as chitosan and poly(vinyl alcohol) (PVA), the prepared novel cellulose membranes exhibited acceptable fluxes and much higher separation factors. All these results demonstrate that cellulose membrane has great application potential in IPA dehydration process.

Attempts were made to enhance cellulose saccharification by cellulase using cellulose dissolution as a pretreatment step. Four cellulose dissolution agents, NaOH/Urea solution, N-methylmorpholine-N-oxide (NMMO), ionic liquid (1-butyl-3-methylimidazolium chloride; [BMIM]Cl) and 85% phosphoric acid were employed to dissolve cotton cellulose. In comparison with conventional cellulose pretreatment processes, the dissolution pretreatments were operated under a milder condition with temperature

Phase state and morphological features of solutions of cellulose blends with rigid-chain thermotropic LC copolyesters and isotropic poly(m-phenyleneisophthalamide) in the highly polar donor solvent N-methylmorpholine-N-oxide are studied by DSC and polarization microscopy. The ternary phase diagram for the cellulose-copolyesters-N-methylmorpholine-N-oxide system is constructed. Rheological characteristics of the prepared solutions are studied using capillary and rotary rheometers under the regimes of continuous and periodic shear deformation. Rheological characteristics of cellulose solutions with copolyesters in N-methylmorpholine-N-oxide with their different phase states are shown to change in accordance with the traditional mechanism of flow for solutions with high specific interactions between their components. However, the character of the rheological behavior of mixtures of cellulose with poly(m-phenyleneisophthalamide) in N-methylmorpholine-N-oxide primarily stems from structural-morphological transformations in solutions taking place upon deformation.

The thermal behavior of cellulose dissolved in ionic liquids was studied in comparison to NMMO solutions. The cellulose solutions were characterized by reaction calorimetry and UV-vis spectroscopy. Generation of chromophoric substances in cellulose/IL solutions is minimized by exposing to temperatures of above 100 °C for longer time periods. Dynamic calorimetric investigations revealed first thermal activities above 180 °C applying EMIMac and above 200 °C for BMIMCl and five other ILs tested. Moreover, even in the case of modified cellulose/IL solutions, e.g., activated charcoal, only a slight decline of onset temperatures was registered compared to modified cellulose/NMMO solutions.

Ultra-lightweight cellulose aerogels can be obtained in three steps: (1) preparation of a cellulose solution in molten N-methylmorpholine-N-oxide monohydrate (NMMO·H2O) at 110–120°C and casting of the viscous mass into moulds; (2) extraction of the solidified castings with ethanol to initiate cellulose aggregation and to remove NMMO·H2O so that the fragile, fine-porous texture of cellulose II is largely retained; and (3) drying of the lyogel using supercritical carbon dioxide (scCO2). According to this approach, cellulosic aerogels were prepared from eight commercial cellulosic materials and pulps and analysed for selected chemical, physicochemical and mechanical parameters. The results reveal that all aerogels obtained from 3% cellulose containing NMMO·H2O melts had a largely uniform mesoporous structure with an average pore size of ∼9–12 nm, surface area of 190–310 m2 g-1, and specific density of 0.046–0.069 g cm-3, but rather low mechanical stability expressed as compressive yield strain of 2.9–5.5%. All samples showed viscoelastic behaviour, with Young's modulus ranging from ∼5 to 10 N mm-2. Doubling the cellulose content in the NMMO·H2O melt from 3% to 6% increased Young's modulus by one order of magnitude. Shrinkage of the fragile cellulose bodies during scCO2 drying was still considerable and is subject to further investigations. Influencing parameters such as scCO2 pressure, cellulose content, regenerating solvent and the number of regenerating baths were optimised.

The syntheses of several perdeuterated substances—some of them isotopically labeled (15N) in addition—are described, which act as direct solvents of cellulose either on their own, such as N-methylmorpholine N-oxide (NMMO), 1-butyl-3-methylimidazolium acetate (BMIM-OAc), or 1-ethyl-3-methylimidazolium acetate (EMIM-OAc), or in combination with auxiliaries, such as N,N-dimethylacetamide (DMAc—for the cellulose solvent DMAc/LiCl). NMMO-d11 (9) was obtained in an eight-step approach from non-labeled diglycolic acid (1) via diethylene glycol-d8 (4) and its bis-tosylate (5), which underwent ring closure with benzylamine to N-benzylmorpholine-d8 (6). Debenzylation, methylation and oxidation completed the synthetic sequence, which was also able to provide the 15N-labeled product (9a) by usage of 15N-benzylamine. DMAc-d9 (14) was obtained from deuterated acetic acid (10) and dimethylamine-d6–carbon dioxide complex (13) in a solvent-free gas-solid reaction with acidic alumina as the catalyst. Employing the CO2-complex of 15N-dimethylamine-d6 afforded the 15N-labeled product 15N-DMAc-d9 (14a) in a similar way. The two ionic liquids EMIM-OAc (21) and BMIM-OAc (22) were obtained from imidazole in three-step sequences starting with butylation and ethylation, respectively. The resulting 1-alkyl imidazoles were purified, and subsequently methylated according to a novel protocol using dimethylcarbonate-d6. Addition of acetic acid-d4 caused traceless degradation of the methylcarbonate anions and exchange for acetate. In all syntheses, the reaction steps were optimized with non-labeled compounds towards high yields and high reproducibility before entering the “hot runs” with deuterated and otherwise isotopically labeled material.

N-methylmorpholine-N-oxide (NMMO) is used widely in the manufacturing of man-made cellulose fibers and functional lyocell fibers due to its environment-friendly advantage. Although chitosan is known as a natural antibacterial polymer it has poor solubility in neutral to basic medium and the antibacterial activity is shown only in acidic medium. Chitosan’s poor solubility in NMMO is the disadvantage for the production of antibacterial lyocell fibers. This paper investigates a more “NMMO soluble” derivative of chitosan, 2-(2-aminoethoxy) ethyl chitosan (AECS). AECS has greatly improved solubility in NMMO hydrate, and stronger antibacterial activity than chitosan. AECS was introduced to modify the lyocell fiber spun in a co-solution of cellulose and AECS in NMMO hydrate. The physical properties and antibacterial activity of the fibers were examined and the results indicated that the modified lyocell fiber, containing more than 2 wt% of AECS, exhibits good antibacterial activity against E. coli and slightly decreased tensile strength compared with unmodified fibers.

The dissolution of thermotropic alkylenearomatic LC copolyesters and isotropic poly(m-phenyleneisophthalamide) in a high-polarity donor solvent, N-methylmorpholine-N-oxide, has been studied. It has been demonstrated that N-methylmorpholine-N-oxide shows high dissolving power with respect to hydrophobic synthetic polymers. In this case, the dissolution of the polymers is accompanied by the formation of crystal solvates of different compositions. With the use of polarization microscopy, DSC, and X-ray diffraction, the stages of formation of crystal solvates have been examined and the phase equilibrium in systems containing crystal solvates has been investigated. Special attention is given to the structural and morphological features of such heterophase systems.

A population of 167 samples were monitored using by rheological, calorimetric, chromatographic and spectroscopic methods, which allows a precise description of the thermal behavior. Hierarchical cluster analysis was used to find similarities between groups of samples. Principal components analysis revealed isoperibolic pressure slope, morpholine and N-methylmorpholine as variables providing most information concerning the thermostability. The onset temperature as the beginning of an exothermicity can be modeled by the combination of detection of amines and aldehydes and subsequent PLS regression.

Additives with functional properties makes the Lyocell process a versatile tool for the creation of new innovative materials beyond the textile sector. Occupying functional groups or active surfaces the additives emphasize the suitability of Lyocell fibers, but simultaneously enhance the complexity of chemical reactions in cellulose/ N-methylmorpholine-N-oxide (NMMO) solutions, respectively. Concerning to the concentration acidic ion exchange resins, activated charcoals, carbon black etc. shift the start of decomposition to lower temperatures, decrease the viscosity, enhance the formation of amines as the main degradation products or cause autocatalytic reactions. New routes in stabilization of modified Lyocell solutions applying a polymeric stabilizer system are described. Using calorimetric, UV/VIS, ESR and HPLC analysis the degradation processes and thermal stability of modified Lyocell solutions compared to the unstabilized were studied. Moreover, as kinetic investigations show a distinguished behavior for modified solutions autocatalytic reactions can be suppressed by the stabilizing system. ESR kinetic study of radicals reveals that formation and recombination rates of radical reactions depend on cellulose concentration in Lyocell solutions and additional ingredients.

Complex formation of scleroprotein models with an N-methylmorpholine N-oxide solvent was studied by the semiempirical PM3 method.

The synthesis of the perdeuterated cellulose solvents NMMO-d11 (9) and N,N-dimethylacetamide-d9 (14) is described. NMMO-d11 was obtained according to a five-step approach from non-labeled diglycolic acid (1) via diethylene glycole-d8 (4) and its bis-tosylate (5), which underwent cyclization with benzylamine to N-benzylmorpholine (6). The removal of the benzyl protecting group, methylation and N-oxidation completed the synthesis. DMAc-d9 (14) was obtained from deuterated acetic acid (10) and dimethylamine–carbon dioxide complex (17) with acidic alumina as the catalyst according to a solvent-free gas–solid reaction. Copyright © 2008 John Wiley & Sons, Ltd.

Regenerated cellulose was prepared from microcrystalline cellulose (MCC) via dissolution in three well-known nonderivatizing systems: ferric chloride/sodium tartarate/sodium hydroxide (FeTNa), sodium hydroxide/thiourea (NaOH/thiourea), and N-methylmorpholine-N-oxide (NMMO) systems. The effect of regeneration using the different systems on the supramolecular structure of the regenerated celluloses was studied using X-ray diffraction and Fourier transform infrared (FTIR). The effect of regeneration on supermolecular structure, morphology, and thermal stability of regenerated celluloses were studied using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The effect of regeneration systems used on the chemical reactivity of cellulose toward carboxymethylation, acetylation, and cyanoethylation reactions was briefly studied. The results showed dependence of all the aforementioned properties on the dissolution reagent used in spite of that all studied reagents cause the same change in cellulose crystalline structure (from cellulose I to cellulose II). The degree of polymerization, crystallinity, and thermal stability of the regenerated cellulose (RC) samples were in the following order: NaOH/thiourea RC > FeTNa RC > NMMO RC. SEM micrograph showed unique surface for the NMMO RC sample. The reactivity of the different regenerated cellulose samples toward carboxymethylation, cyanoethylation, and acetylation depended mainly on the reaction system and conditions used rather than on crystallinity of regenerated cellulose. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

This study investigated effects of chemical pretreatment with N-methylmorpholine-N-oxide (NMMO) on methane yields of rice straw, cocoa bean shell, and hazelnut skin. Three lignocellulosic materials were separately pretreated with NMMO at 120°C for 3 h. Subsequently, batch biomethane production tests were performed under mesophilic (37°C ± 2°C) conditions, also with the untreated feedstocks, to provide methane production baseline data. Pretreatment was particularly effective for rice straw, with an 82% increased biomethane production yield from 206 mL CH4/g volatile solids (VS) obtained with the untreated substrate. A lower enhancement of the biomethane yield from 199 to 226 mL CH4/g VS (i.e., 14% increase) was observed for cocoa shell. For hazelnut skin, NMMO pretreatment resulted in a faster digestion rate in the initial 7 days, increasing the biomethane yield from 17 to 27 mL CH4/g VS·day. However, the cumulative biomethane yield after 40 days was not affected by NMMO pretreatment.

Three decades after N-methylmorpholine N-oxide (NMMO) was first introduced as a solvent for direct cellulose dissolution, the usage of NMMO in the fiber-making industry has flourished throughout the world. This success attracts the attention of researchers working in lignocellulosic biomass fractionation to use NMMO as an agent for lignocellulosic pretreatment in biofuel production. The present chapter presents the current status of NMMO for the pretreatment of lignocellulosic biomass for further fermentation to biofuels.

International audience; The aim of this work was to study the effect of the solvent N-methylmorpholine-N-oxide (NMMO) to pre-treat Nannochloropsis oculata before the anaerobic digestion process. The results indicated that the pre-treatment affects the characteristics of the cell wall, which consequently becomes more susceptible to the microorganisms attack during anaerobic digestion. The methane production was increased by 43% after the pre-treatment, from 238 ± 6 mLCH4/gVS until 339 ± 4 mLCH4/gVS. On the contrary, the methane production from Chlorella vulgaris decreased after the pre-treatment from 251 ± 4 mLCH4/gVS to 231 ± 3 mLCH4/gVS. The failure on the pre-treatment was attributed to the particular characteristics of the substrate in consequence of a previous drying step.

O-carboxymethylated chitosan (O-CMCh) aqueous solution (I) and Ethyletheramine Chitosan (EACS) aqueous solution (II) were blended with cellulose N-methylmorpholine N-oxide solution, and corresponding polyblends (Polyblend I and II) were obtained. The rheology of this three liquids, (cellulose solution, Polyblend I and II), was investigated in this study. Then the influence on rheology, because of the addition of chitosan derivative, was discussed.

Degradation processes of N-methylmorpholine-N-oxide monohydrate (NMMO), cellulose and cellulose/NMMO solutions were studied by high performance liquid chromatography (HPLC) and electron spin resonance (ESR) spectroscopy. Kinetics of radical accumulation processes under UV (λ = 248 nm) excimer laser flash photolysis was investigated by ESR at 77 K. Beside radical products of cellulose generated and stabilized at low temperature, radicals in NMMO and cellulose/NMMO solutions were studied for the first time in those systems and attributed to nitroxide type radicals ∼CH2–NO•–CH2∼ and/or ∼CH2–NO•–CH3∼ at the first and methyl •CH3 and formyl •CHO radicals at the second step of the photo-induced reaction. Kinetic study of radicals revealed that formation and recombination rates of radical reaction depend on cellulose concentration in cellulose/NMMO solutions and additional ingredients, e.g., Fe(II) and propyl gallate. HPLC measurements showed that the concentrations of ring degradation products, e.g., aminoethanol and acetaldehyde, are determined by the composition of the cellulose/NMMO solution. Results based on HPLC are mainly maintained by ESR that supports the assumption concerning a radical initiated ring-opening of NMMO.