Synthesis of a new pyridine-containing diamine and related polyimide

A new kind of aromatic diamine monomer containing pyridine unit,2,6-bis[4-(4-aminophenoxy)phenoxy]pyridine(BAPP),was synthesized in three steps,using hydroquinone as starting material.A novel pyridine-containing polyimide was prepared from the resulting diamine BAPP with 4,4 -oxydiphthalic anhydride(ODPA) via a conventional two-step thermal imidization method.The resulting polyimide exhibits excellent solubility,film-forming capability and high thermal resistance.

Synthesis and Characterization of Novel Polyimides Based on Pyridine-containing Diamine

A new aromatic diamine monomer containing pyridine unit, 2,6-bis （4-aminophenoxy- 4＇-benzoyl）pyridine（BABP）, was synthesized in three steps, starting from 2,6-pyridinedicarboxyl chloride. A series of novel pyridine-containing polyimides were prepared v/a the polycondensation of BABP with various aromatic dianhydrides through poly（amic acid） precursors, and thermal or chemical imidization of the precursors. The polyimides exhibit desirable properties, e.g., good solubility in N-methyl-2-pyrrolidone and m-cresol, excellent thermal stability and film-forming capability, as well as high inherent viscosity, indicating high molecular weight.

Preparation of Environmentally Friendly Urea-Hexanediamine-Glyoxal(HUG)Resin Wood Adhesive

Using non-toxic,low-volatile glyoxal to completely replace formaldehyde for preparing urea-glyoxal(UG)resin adhesive is a hot research topic that could be of great interest for the wood industry.However,urea-glyoxal(UG)resins prepared by just using glyoxal instead of formaldehyde usually yields a lower degree of polymerization.This results in a poorer bonding performance and water resistance of UG resins.A good solution is to pre-react urea to preform polyurea molecules presenting already a certain degree of polymerization,and then to condense these with glyoxal to obtain a novel UG resin.Therefore,in this present work,the urea was reacted with hexamethylene diamine to form a polyurea named HU,and then this was used to react it with different amounts of glyoxal to synthesize hexamethylenediamine-urea-glyoxal(HUG)polycondensation resins,and to use this for bonding plywood.The results show that the glyoxal can well react with HU polyuria via addition and schiff base reaction,and also the HUG resin exhibits excellent bonding strength and water resistance.The shear strength of the plywood bonded with this HUG at 160°C hot press temperature as high as 1.93 MPa,2.16 MPa and 1.61 MPa,respectively,which meets the requirement of the China national standard GB/T 9846-2015(≥0.7 MPa),and can be a good choice as a wood adhesive for industrial application.

Stoichiometry and Stability Constant Values for Copper (II) Chelates with Ethylene Diamine in Deep Eutectic Solvents (DES) (Ethaline) Solutions

In this study we used the deep eutectic solvents (ionic liquids) to investigate the reaction between copper (II) with ethylene diamine (en). Two of the existing methods for analyzing spectrophotometric measurements have been applied for establishing, the stoichiometry and whenever possible, the stability constants of the chelates formed. The method of continuous variations was necessary to determine first whether, the metal ion and the ligand ethylene diamine form one or more than one chelate, when more than one chelate formed, the results obtained depend on the wavelength and for meaningful conclusions the wavelengths were carefully selected. The empirical formulae of the chelates were further substantiated by the molar ratio method. The effect of time and temperature on the formation and stability of these chelates in solution is also studied. The stability constants, K1 and K2 for the copper (II) chelates were calculated, though reliable, and are comparable to literature values.

Value of combining the serum D-lactate, diamine oxidase, and endotoxin levels to predict gut-derived infections in cancer patients

Objective:This is a retrospective observational cohort study.The objective of this retrospective observational cohort study was to evaluate the value of the combined serum D-lactic acid,diamine oxidase(DAO),and endotoxin levels to predict intestinal barrier impairment and gut-derived infection(GDI)in cancer patients.Methods:Cancer patients receiving chemotherapy or palliative care treatment at our hospital were enrolled in the study.The serum concentrations of DAO,D-lactic acid,and endotoxin were determined using the intestinal barrier function biochemical index analysis system.The patients'infection information came from the hospital's Medicom Prescription Automatic Screening System and themedical records.Three hundred fifty-three cancer patients were included in the study(53.8%female,73.7%cancer stage IV,27.8%had bowel obstruction).Results:The total incidence of GDI was 33.4%(118/353).The median length of hospital stay was 16 days for patients with GDI,compared with 7 days for patients without GDI(P<0.001).The media hospitalization costs were¥27,362.35 for patients with GDI compared with¥11,614.08 for patients without GDI(P<0.001).The serum concentrations of DAO,D-lactic acid,and endotoxin were significantly higher in patients with GDI.As malignant bowel obstruction(MBO)worsened,the concentrations of DAO,D-lactic acid,and endotoxin increased.Multivariate logistic regression models revealed that the DAO,endotoxin,IL-6,and C-reactive protein levels were significantly associated with an increased risk of GDI.In addition,we also found a fivefold increased risk of infection in patients withMBO compared with those without bowel obstruction(OR=6.210,P<0.001).All of the areas under the receiver operating characteristic curve(AUCs)for DAO,D-lactate,and endotoxin to predict GDI were<0.7(AUC=0.648,P<0.001;AUC=0.624,P<0.01;AUC=0.620,P<0.01,respectively).However,when the parameters were combined(DAO+D-lactate+endotoxin),the predictive power increased significantly(AUC=0.797,P<0.001).Moreover,combining these intestinal barrier indicators and the presence of MBO had better power to predict GDI than either alone(AUC=0.837,P<0.001).Conclusions:Combining the serum DAO,D-lactic acid,and endotoxin levels was a better predictor of GDI than any of the indicators alone,and combining these with the diagnosis of MBO could further improve the efficacy for predicting GDI.

Changes of plasma D(-) -lactate, diamine oxidase and endotoxin in patients with liver cirrhosis

BACKGROUND: Plasma D(-)-lactate and diamine oxidase (DAO) can reflect patients' intestinal mucosal condition. We evaluated the changes of plasma D (-)-lactate, DAO and endotoxin activities and their significance in patients with liver cirrhosis. METHODS: Fifty liver cirrhosis patients were enrolled into experimental group and 30 healthy people into control group. The plasma levels of D(-)-lactate, DAO and endo- toxin were detected spectrophotographically. RESULTS: The level of D(-)-lactate was significantly high- er in the experimental group than that in the control group (P<0.01). Significant differences of D (-)-lactate levels were observed in Child-Pugh subgroups of the experimen- tal group (P <0. 01). The level of DAO was significantly higher in the experimental group than that in the control group (P <0.01), but the level of DAO in Child-Pugh sub- group C was significantly lower than that in Child-Pugh subgroup B (P<0.01). The level of endotoxin was signifi- cantly increased in the experimental group except Child Pugh subgroup A (P<0.01). The plasma levels of D(-) lactate, DAO and endotoxin were positively correlated with each other (P<0.01). CONCLUSIONS: The data suggest that both plasma D(-) lactate and DAO activity are sensitive markers for early diagnosis of gut failure and endotoxemia in patients with liver cirrhosis. The impairment of intestinal barrier func- tion may be one of the critical reasons for deterioration of liver cirrhosis.

The production of biobased diamines from renewable carbon sources: Current advances and perspectives

Bio-based diamines are considered to be a promising alternative to traditional fossil-fuel-based diamines,the important platform chemical for the synthesis of polymer materials.In this review,the current status of the art of the synthesis of aliphatic and aromatic diamines from renewable biomass are considered.In the case of aliphatic diamines,we describe strategies for biologically producing diamines with different carbon numbers including 1,3-diaminopropane,1,4-butanediamine,1,5-pentanediamine,1,6-diaminohexane,1,8-diaminooctane,1,10-diaminodecane,and 1,12-diaminododecane.In addition,aromatic diamines produced from various kinds of renewable biomass,including lignin,cashew nut shell,and terpenoids,are reviewed here.Furthermore,the application of typical diamines in synthesis of polyurethane and polyamide are also reviewed.

Soluble intercellular adhesion molecule-1,D-lactate and diamine oxidase in patients with inflammatory bowel disease

AIM： To study the levels of serum soluble intercellular adhesion molecule-1 （sICAM-1）, plasma D-lactate and diamine oxidase （DAO） in patients with inflammatory bowel disease （IBD）, and the potential clinical significance. METHODS： Sixty-nine patients with IBD and 30 healthy controls were included in this study. The concentration of sICAM-1 was detected with enzyme-linked immunosorbent assay, the level of D-lactate and DAO was measured by spectroscopic analysis, and the number of white blood cells （WBC） was determined by routine procedure. RESULTS： The levels of sICAM-I, DAO, and WBC in IBD patients were significantly higher than those in the control group （P 〈 0,01）, sICAM-I in IBD patients was found to be closely related to the levels of DAO and D-lactate （212.94 ± 69.89 vs 6.35 ± 2.35, P = 0.000）, DAO 212.94 ± 69.89 vs 8.65 ± 3.54, P = 0.000） and WBC （212.94 ± 69.89 vs 7.40 ± 2.61, P = 0.000）, but no significant difference was observed between patients with ulcerative colitis and patients with Crohn＇s disease. The post-treatment levels of sICAM-I, D-lactate and WBC were significantly lower than before treatment （sICAM-I 206.57 ± 79.21 vs 146.21 ± 64.43, P = 0.000）, （D-lactate 1.46 ± 0.94 vs 0.52± 0.32, P = 0.000） and （WBC 7.24 ± 0.2.33 vs 5.21 ± 3.21, P = 0.000）. CONCLUSION： sICAM-1, D-lactate and DAO are closely related to the specific conditions of IBD, and thus could be used as a major diagnostic index.

Ultrasonicwave-assisted tandem-reaction for synthesis of symmetrical vicinal diamines

A practical synthesis of symmetrical vicinal diamines with broad chemistry scope is described. The key step is the ultrasonicwave promoted tandem-reaction, two-step reaction sequence combining Mannich double condensations with benzo- triazole, glyoxal and primary or secondary amines and reduction of the bis（benzotriazole）-adducts with sodium borohydride proceeded smoothly in tetrahydrofuran in high yield at room temperature.

Synthesis of 2-methylpyrazine from cyclocondensation of ethylene diamine and propylene glycol over promoted copper catalyst

The 2-methylpyrazine was synthesized by catalytic reaction of ethylene diamine and propylene glycol at 380 ℃. The alumina supported copper catalysts with promoter were prepared by impregnation method, characterized by ICP-AES, BET and TPR. The results demonstrated that the dehydrogenation was improved by addition of chromium promoter. The selectivity of 2-methylpyrazine reached 84.75%, while the conversions of reactants were also enhanced.

Green and selective hydrogenation of aromatic diamines over the nanosheet Ru/g-C_(3)N_(4)-H_(2) catalyst prepared by ultrasonic assisted impregnation-deposition method

In this study,nanosheet g-C_(3)N_(4)-H_(2) was prepared by thermal exfoliation of bulk g-C_(3)N_(4) under hydrogen.A series of Ru/g-C_(3)N_(4)-H_(2) catalysts with Ru species supported on the nanosheet g-C_(3)N_(4)-H_(2) were synthesized via ultrasonic assisted impregnation-deposition method.Ultrafine Ru nanoparticles(<2 nm)were highly dispersed on nanosheet g-C_(3)N_(4)-H_(2).Strong interaction due to Ru-Nx coordination facilitated the uniform distribution of Ru species.Meanwhile,the involvement of surface basicity derived from abundant nitrogen sites was favourable for enhancing the selective hydrogenation performance of bi-benzene ring,i.e.,almost complete 4,40-diaminodiphenylmethane(MDA)conversion and>99%4,40-diaminodicyclohexylmethane selectivity,corresponding to a reaction activity of 35.7 mol_(MDA) mol_(Ru)^(-1) h^(-1).Moreover,the reaction activity of catalyst in the fifth run was 36.5 mol_(MDA) mol_(Ru)^(-1) h^(-1),which was comparable with that of the fresh one.The computational results showed that g-C_(3)N_(4) as support was favorable for adsorption and dissociation of H_(2) molecules.Moreover,the substrate scope can be successfully expanded to a variety of other aromatic diamines.Therefore,this work provides an efficient and green catalyst system for selective hydrogenation of aromatic diamines.

Selective flotation of smithsonite, quartz and calcite using alkyl diamine ether as collector

The flotation separation of smithsonite from calcite and quartz using a alkyl diamine ether(GE-609)as the collector was investigated through micro-flotation experiments and the real ore flotation experiments.The results show that GE-609exhibits good collecting capability to three minerals without selectivity.The presence of sodium sulfide enhances the flotation of smithsonite and calcite while inhibits quartz.Moreover,both sodium silicate and sodium hexametaphosphate exhibit good selective inhibition to calcite.The real ore test results show that a zinc concentrate containing23.51%Zn with the recovery of71.02%is obtained in the closed-circuit test.To understand the adsorption of GE-609on smithsonite surface,zeta potential measurement and FTIR analysis were carried out,and the results indicate that the collector GE-609can adsorb on smithsonite surface through both electrostatic adsorption and chemical adsorption,and the presence of sodium sulfide enhances the adsorption of GE-609.

Synthesis and dehydrogenation properties of NaZn(BH4)3·en and NaZn(BH4)3·2en(en= ethylene diamine)

Two new hydrogen storage compounds,Na Zn(BH4)3·en and Na Zn(BH4)3·2en(en=ethylene diamine)are synthesized by a solution method.They can release 6.4 wt%and 6.3 wt%pure hydrogen below 200℃,respectively,demonstrating the potential to be used as hydrogen carriers.Additionally,their dehydrogenation products,thermodynamics and kinetics are well characterized and analyzed.Results shows that the stronger Zn-N interactions and the Hδ+–Hδ-interactions are significant for their stability below 100℃,relatively low decomposition temperatures and elimination of gas impurities.

Cu(I)/Diamine-catalyzed Aryl-alkyne Coupling Reactions

CuI/ethylene diamine/K2CO3/dioxane is shown to be a useful system for the cross coupling reactions of various aryl iodides and bromides with aryl and alkyl alkynes. Compared to the conventional Sonogashira reactions, the new procedure is free of palladium and phosphines.

Synthesis of anew siloxane-containing diamine and related polyimide

A novel siloxane-containing diamine, bis[4-(p-aminophenoxy)phenoxy]dimethylsilane (APPMS), was successfully synthesized in three steps using hydroquinone as starting material, which was reacted with 4,4′-oxydiphthalic anhydride (ODPA) via a conventional two-step thermal or chemical imidization method to produce a new siloxane-containing polyimide. The resulting polyimide exhibited excellent solubility, and film-forming capability.

Synthesis and characterization of novel polyimides based on thiazole-containing diamine

A new kind of aromatic diamine monomer containing thiazole unit, 2-amino-5-（4-aminophenyl）-thiazole （AAPT）, was synthesized in three steps, starting from 4-nitroacetophenone. A novel thiazole-containing polyimide was prepared via the polycondensation of AAPT with 6FDA by one-step method. The resulting polyimide exhibits excellent solubility, film-forming capability and high thermal resistance.

Synthesis of a New Asymmetrical Ether Diamine with Aromatic Structure and Related Polyimide

A new aromatic asymmetrical ether diamine, 1,4-bis（3＇,4’-diaminophenoxy）benzene 3 was synthesized in three steps, using hydroquinone as starting material. A new aromatic polyimide containing asymmetrical diaryl ether segments was prepared from the resulting diamine with 4,4＇-oxydiphthalic anhydride （ODPA） via a conventional two-step thermal or chemical imidization method. The resulting polyimide exhibits high thermal resistance, excellent solubility, film-forming capability, high mechanical strength and modulus.

Influences of Diamines on the Morphologies and the Chemical, Thermal, and Mechanical Properties of Polyurethane-Imide Elastomers

Polyurethane-imide elastomers (PUIEs) are formed from isocyanate, polyol, acid anhydride, and diamine by liquid polymerization. Unfortunately, many of the diamines have rarely been applied to the formation of PUIEs. Hence, investigating the effect of diamines on PUIEs remains a challenge in polymer chemistry. Herein, PUIEs prepared from 4,4'-diphenylmethane diisocyanate (MDI), polytetramethylene glycol (Mw: 1000), pyromellitic dianhydride, and aromatic diamines (such as p-phenylene diamine, 4,4'-oxydianiline, and 1,3-bis(4-aminophenoxy)benzene), and aliphatic diamines (such as 1,2-ethylene diamine, 1,6-hexamethylene diamine, and 1,12-dodecamethylene diamine) were synthesized by liquid polymerization. The morphologies and the chemical, thermal, and mechanical properties of the various PUIEs were investigated. The obtained elastomeric sheets were characterized in terms of the following tests and methods: solubility and swelling tests, X-ray diffraction and differential scanning calorimetry, dynamic mechanical analysis and thermogravimetric analysis, tensile tests, nuclear magnetic resonance spectroscopy, infrared spectroscopy, atomic force microscopy, contact angle microscopy, and scanning electron

Synthesis of Toluene-2,4-Bisurea from 2,4-Toluene Diamine and Urea and the Reaction Kinetics

Toluene-2,4-bisurea (TBU) is an important intermediate for urea route to dimethyl toluene-2,4-dicarbamate and the study on TBU synthesis via the reaction of 2,4-toluene diamine (TDA) and urea is of great significance. Firstly, thermodynamic analysis shows that the reaction is exothermic and a high equilibrium conversion of TDA is expected due to its large reaction equilibrium constant. Secondly, under the suitable reaction conditions, 130 °C, 7 h, and molar ratio of TDA/zinc acetate/urea/sulfolane 1/0.05/3.5/10, TDA conversion is 54.3%, and TBU yield and selectivity are 39.8% and 73.3% respectively. Lastly, the synthesis of TBU is a 1st order reaction with respect to TDA and the reaction kinetics model is established. This work will provide useful information for commercializing the urea route to toluene-2,4-dicarbamate (TDC).

Synthesis, Crystal Structure and Thermal Properties of N,N′-Bis(5,5-dimethyl-2-phospha-2-thio-1,3-dioxan-2-yl) Ethylene Diamine

The title compound N,N＇-bis（5,5-dimethyl-2-phospha-2-thio-1,3-dioxan-2-yl） ethylene diamine （DPTDEDA, C12H26N2O4P2S2） was synthesized by the reaction of neopentyl glycol, phosphorus thio-chloride and 1,2-ethylenediamine, and characterized by elemental analysis, IR and ^1H NMR spectra. Its crystal structure was determined by single-crystal X-ray diffraction analysis and the thermal property was analyzed by TG analysis. The crystal structure belongs to monoclinic, space group P21/c, with a = 14.557（16）, b = 11.299（12）, c = 12.163（13）A,β = 98.707（19）^o, Dc = 1.305 g/cm^3, Z = 4, γ = 0.71073A,μ（MoKa） = 0.447 mm^-1, Mr = 388.41, V = 1977（4）A3, F（000） = 824, S = 1.107, the final R = 0.0478 and wR = 0.0810 for 1738 observed reflections （I 〉 2σ（I））. X-ray analysis reveals that the crystal structure is centrosymmetrically distributed through 1,2-ethylenediamine to join two distorted six-membered rings. The weak N-H…S interactions are observed and link the molecules into sheets. TG analysis shows that the title compound has good thermal stability and char-forming capability, which are required for an excellent intumescent fire retardant.