- Efficient Sc triflate mesoporous-based catalysts for the synthesis of 4,4′-methylenedianiline from aniline and 4-aminobenzylalcohol
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Sc triflate mesoporous-based catalysts have been prepared using a two-step strategy (i.e., Atrane method) based on the formation of the hierarchic bimodal porosity in the first step and the formation of Sc triflate complexes at the materials surface in the second step. All solids were analyzed by EPMA, surface area, and pore size values, XRD, TEM, FTIR, and 45Sc NMR static spectra. The catalysts have been investigated in the synthesis of 4,4′-methylenedianiline (4,4′-MDA) from aniline and 4-aminobenzylalcohol. 4,4′-MDA was obtained with selectivities over 85.0% for a conversion of aniline of 31%, at 80 °C and after 24 h. Using microwaves, selectivities of 90% in 4,4′-MDA were reached in only 3 h. Important key parameters influencing the catalytic performances seem to be the scandium content and the nature of the formed Sc species. By replacing formaldehyde with 4-aminobenzylalcohol, the necessity of additional steps for neutralization and separation of the wastes can be eliminated.
- Candu, Natalia,Ciobanu, Madalina,Filip, Petru,Haskouri, Jamal El,Guillem, Carmen,Amoros, Pedro,Beltran, Daniel,Coman, Simona M.,Parvulescu, Vasile I.
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- PROTODEALKYLATION OF BIS(AMINOPHENYL)METHANES
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Contrary to earlier reports, the formation of bis(aminophenyl)methanes in the acid-catalyzed condensation of aniline and formaldehyde can result in carbon-carbon bond cleavage proceeding via an ipso protodealkylation mechanism.
- Whitman, Peter J.,Frulla, Floro F.,Temme, George H.,Stuber, Fred A.
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- Chemical behaviour of seven aromatic diisocyanates (toluenediisocyanates and diphenylmethanediisocyanates) under in vitro conditions in relationship to their results in the Salmonella/microsome test
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There are conflicting results on the mutagenicity of toluenediisocyanate (TDI) and diphenylmethanediisocyanate (MDI). It was found that the organic solvent chosen to dissolve the compounds dictates the outcome of the bacterial tests. The Salmonella/microsome tests showed uniformly mutagenic effects for all the compounds that were predissolved in DMSO. Due to the instability of aromatic diisocyanates in DMSO this solvent was replaced by ethyleneglycoldimethylether (EGDE). TDI and MDI endured the dissolving and were therefore still available for the subsequent bacterial tests. Furthermore, no aromatic diamines (TDA or MDA) could be detected in EGDE prior to the start of the assays. The Salmonella/microsome tests, however, revealed unexpected differences between TDI and MDI. As previously published the four types of MDI showed negative results, whereas the data presented in this paper demonstrated mutagenic effects of all three types of TDI if EGDE is the solvent. To gain deeper insight into the chemical changes that occurred during the Salmonella/microsome test, the possible reactions were modelled in the laboratory by mixing predissolved diisocyanates with a defined surplus of water and monitoring the progress of the chemical reactions by analytical methods. Additionally, the quality of the model was checked by exposing solutions of 2,6-TDI and 4,4'-MDI to the real biological test environment. In both cases, the reaction patterns of TDI were different to those of MDI. Within 1 min, which is the maximum time needed to mix the predissolved compounds with water before they are poured onto the agar plate, the TDI content was reduced in favour of different ureas and TDA. In addition water was replaced by the complete set of test ingredients. While the TDA content remained more or less constant, the amount of residual TDI was reduced considerably. Reactions of MDI were markedly slower than those of TDI. More than 90% of the predissolved MDI remained intact when it was mixed with water. The biological test ingredients accelerated the reduction of the MDI content. Within 45 s, more than two thirds of the MDI disappeared. Evidently, the chemical reactions continue during incubation. It is assumed that the contrasting results of TDI and MDI in the Salmonella/microsome test are due to the different reaction patterns-and reaction products-of the predissolved diisocyanates created under the specific conditions of the test. These findings indicate that the chemical interactions between reactive test compounds and solvents or test media need to be considered in the interpretation of the relevance of test results. Copyright (C) 1999 Elsevier Science B.V.
- Seel,Walber,Herbold,Kopp
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- Hydrogenation of arenes, nitroarenes, and alkenes catalyzed by rhodium nanoparticles supported on natural nanozeolite clinoptilolite
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Abstract Nanozeolite clinoptilolite supported rhodium nanoparticles (Rh/NZ-CP) has been prepared and characterized by a variety of techniques, including XRD, BET, TEM, EDX, ICP-OES and XPS analysis. This nanomaterial contains 2 wt% Rh in the range of 5-20 nm metallic nanoparticles distributed on nanozeolite. The catalytic performance of Rh/NZ-CP was evaluated by the hydrogenation of arenes, nitroarenes, and alkenes under moderate reaction conditions. The prepared nanocatalyst can be facilely recovered and reused many times without significant decrease in activity and selectivity. The high catalytic activity, thermal stability and reusability, simple recovery and eco-friendly nature make present catalyst as a unique catalytic system, which is particularly attractive in green chemistry.
- Baghbanian, Seyed Meysam,Farhang, Maryam,Vahdat, Seyed Mohammad,Tajbakhsh, Mahmood
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- Reaction network and mechanism of the synthesis of methylenedianiline over dealuminated Y-type zeolites
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The reaction network and mechanism of the synthesis of methylenedianiline (MDA) from the condensation product of aniline and formaldehyde (aminal) on microporous acidic materials has been elucidated. The first step of the reaction, the decomposition of the aminal to N-benzylanilines, is limited by film diffusion, and the second and significantly slower step, the acid catalyzed rearrangement of these intermediates to MDA, is controlled by microkinetics on mesoporous dealuminated Y-type zeolites. This second step of the reaction network is limited by pore diffusion on zeolite BEA as an example for non-mesoporous materials. Based on time-concentration profiles, we were able to determine the reaction orders of the initial decomposition of the aminal to one and two for the following rearrangement of para-aminobenylaniline to 4,4′-MDA. From the kinetic data we deduced an SN2-type reaction mechanism and a complex reaction network, which is able to simulate the observed concentration profiles. The aniline to formaldehyde ratio in the starting mixture had a negligible influence on the final product distribution.
- Salzinger, Michael,Lercher, Johannes A.
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- Towards an industrial synthesis of diamino diphenyl methane (DADPM) using novel delaminated materials: A breakthrough step in the production of isocyanates for polyurethanes
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Delaminated materials ITQ-2, ITQ-6 and ITQ-18 are very efficient catalysts of zeolitic nature for the synthesis of diamino diphenyl methane (DADPM), the polyamine precursor in the production of MDI for polyurethanes. The exfoliation process results in excellent accessibility of their active sites to reactant molecules as well as fast desorption of products. These catalysts present higher activity and slower rates of deactivation than their corresponding zeolites. Moreover, the topology of the delaminated structure imposes a precise control of the isomer distribution, offering an additional flexibility in the synthesis of DADPM. By optimizing the process conditions it is possible to achieve final DADPM crude under industrial production specifications with ITQ-18. This catalyst represents a real chance for replacing HCl in the industrial production of DADPM.
- Botella,Corma,Carr, Robert H.,Mitchell, Christopher J.
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- Lewis acid solid catalysts for the synthesis of methylenedianiline from aniline and formaldehyde
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A catalyst containing Hf4+ and Zn2+ supported on silica has been found to be highly effective for the synthesis of methylenedianiline (MDA), an indispensable precursor in the polyurethane industry. Its performance was further improved when the silica support was replaced by silica-alumina, which resulted in a catalyst that was both active and selective, as indicated by the high MDA yield and high 4,4′–MDA/(2,2′–MDA + 2,4′–MDA) isomer ratio obtained. Furthermore, the catalyst also gave an appreciable oligomeric MDA (OMDA) yield and was noticeably more stable than the zeolites that were used in comparative tests: it could be used in at least five consecutive runs without any significant loss in activity. The combination of Br?nsted and Lewis acidity strongly increases the overall activity and yields a catalyst that represents a remarkably stable and reusable alternative to the commonly studied systems for this reaction.
- Cheung, Ka Yan,De Baerdemaeker, Trees,De Vos, Dirk,Gordillo, Alvaro,Marquez, Carlos,Parvulescu, Andrei-Nicolae,Tomkins, Patrick
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- HETEROGENEOUS SYNTHESIS OF METHYLENE DIANILINE
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The present invention relates to a catalytic material for the preparation of one or more of 4,4'- methylenedianiline, 2,2'-methylenedianiline, 2,4'-methylenedianiline, and oligomers of two or more thereof, the catalytic material comprising an oxidic support, wherein the oxidic support comprises an element EOS1 selected from the group consisting of Ti, Zr, Al, Si, and mixtures of two or more thereof, and further comprising a supported material supported on the oxidic support, wherein the supported material comprises an element ESM1 selected from the group consisting of Ti, Zr, V, Nb, Ta, Mo, W, Ge, Sn, Sc, Y, La, Ce, Nd, Pr, Hf, Cr, Fe, Co, Ni, Cu, Zn, Pb, and mixtures of two or more thereof. Further, the present invention relates in particular to a process for the preparation of a catalytic material and to a process for the preparation of one or more of 4,4'-methylenedianiline, 2,2'-methylenedianiline, 2,4'-methylenedianiline and oligomers of two or more thereof.
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Page/Page column 33-35
(2021/06/22)
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- METHOD OF PRODUCING DIAMINES AND POLYAMINES OF THE DIPHENYLMETHANE SERIES
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The invention relates to a method for producing diamines and polyamines of the diphenylmethane series, by condensing aniline and formaldehyde followed by an acid-catalysed rearrangement at different production capacities with alteration of the isomer composition in the resulting diamines of the diphenylmethane series (altering the 2,4′-MDA content). Adapting the molar ratios of the total used aniline to the total used formaldehyde and of the total used acid catalyst to the total used aniline, and adapting the reaction temperature, allows the rearrangement reaction to be fully completed despite the change in dwell time inevitably associated with a change in production capacity, and allows the formation of undesired by-products to be avoided as far as possible; the intended modification to binuclear content is likewise achieved.
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Paragraph 0141-0143
(2020/03/28)
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- METHOD OF PRODUCING DIAMINES AND POLYAMINES OF THE DIPHENYLMETHANE SERIES
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The invention relates to a method for producing diamines and polyamines of the diphenylmethane series, by condensing aniline and formaldehyde followed by an acid-catalysed rearrangement at different production capacities with alteration of the content of diamines of the diphenylmethane series (altering the binuclear content). Adapting the molar ratio of the total used aniline to the total used formaldehyde and adapting the reaction temperature allows the rearrangement reaction to be fully completed despite the change in dwell time inevitably associated with a change in production capacity, and allows the formation of undesired by-products to be avoided as far as possible; the intended modification to binuclear content is likewise achieved.
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Paragraph 0136-0167
(2020/05/02)
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- Method for synthesizing 4, 4'-MDA by means of aniline
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The invention discloses a method for synthesizing 4, 4'-MDA by means of aniline. ZrOCl 8HO, Ce(NO) 6HO, nickel nitrate, aniline and formaldehyde are used as main raw materials, the Bronsted-Lewis double-acid functionalized catalyst prepared by means of ZrOCl 8HO and Ce(NO) 6HO has Bronsted acid and Lewis acid sites at the same time, and the feature of double acidity is fused; according to the used raw materials, the mass ratio of aniline to formaldehyde is 6: 1, the mass ratio of N-methylimidazole to ZrOCl 8HO to Ce(NO) 6HO is 2: 3, and the mass ratio of composite oxide to nickel nitrate is 1: 1. According to the 4, 4'-MDA synthesis process, operation is easy, the cost of the catalyst is low, and the applicability is high; compared with traditional solidand liquid acid catalysts, the catalyst has larger development potential and application value, and has an excellent catalytic effect on the MDA synthesis reaction.
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Paragraph 0008-0029
(2018/05/16)
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- By using micro-reactor preparation 4, 4' - diamino diphenylmethane derivatives (by machine translation)
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The invention discloses the use of micro-reactor for preparing the 4, 4 '- diamino diphenylmethane derivatives, water, inorganic acid of the reaction liquid and the formaldehyde solution respectively through the advection pump conveying to the micro-reactor in the two inlets, in micro-contacting in a reactor, mixing and reaction, then cooling, sodium hydroxide aqueous solution, a white precipitate is separated out, filtering, drying, to obtain 4, 4' - diamino diphenylmethane derivatives (MDA, MDT or MOCA) crude, recrystallized with ethanol, filtering, drying, to get the pure product. The invention adopts the micro-reactor technology to achieve a 4, 4' - diamino diphenylmethane derivatives of continuous preparation, easy large-scale production; the reaction speed, reaction time is greatly shortened. (by machine translation)
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Paragraph 0048; 0049; 0050; 0051-0055; 0066; 0067
(2017/08/31)
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- Synthetic method for 4-(3-cyanobenzyl)phenylacetylimine
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The invention discloses a synthetic method for 4-(3-cyanobenzyl)phenylacetylimine, which belongs to the technical field of organic synthesis. The synthetic method of the invention has the advantages of low risks, high productivity and small influence on the environment and overcomes the disadvantages of low production yield, high risks, great influence on the environment, unsuitability for large-scale industrial production and the like of conventional synthetic methods for 4-(3-cyanobenzyl)phenylacetylimine.
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Paragraph 0005; 0010
(2018/02/04)
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- Continuous preparation of solid acid catalysis 4, the 4 [...] -diamino diphenylmethane derivatives (by machine translation)
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The invention discloses a continuous preparation of solid acid catalysis 4, the 4 [...] -diaminodiphenylmethane derivative method, the method to aniline derivatives as raw materials with formaldehyde, in one stage or two stage fixed-bed reactor to conduct the condensation reaction of the solid acid catalysis of the reaction, the reaction liquid airspeed is 2-9h -1, obtain 4, the 4 [...] -diamino diphenylmethane derivatives (MDA, MDT, MOCA). The invention uses a solid acid Hβ, HY, HZSM-5 molecular sieve to replace the hydrochloric acid, the traditional inorganic acid catalyst such as sulfuric acid, the reaction is carried out continuously, the method of the invention process is simple, short reaction time, the productivity is high, high yield, no corrosion to equipment, environmental protection, especially suitable for continuous industrial production. (by machine translation)
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Paragraph 0037; 0067
(2016/10/08)
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- Compounding method for 4,4'-diaminodiphenylmethane
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The invention discloses a compounding method for 4,4'-diaminodiphenylmethane and belongs to the technical field of organic compounding. The compounding method comprises the following steps: firstly, adding formaldehyde solution, hydrogen chloride solution and sulfuric acid solution into nitrobenzene, thereby generating p-nitrobenzaldehyde; adding HNO3 solution and H2SO4 solution into phenol, and then uniformly stirring, and performing water bath temperature rise and ice bath temperature decrease, thereby acquiring p-nitrophenol; mixing p-nitrobenzaldehyde and p-nitrophenol which are acquired at two times, and adding Fe, thereby further generating 4,4'-dinitrobenzene methyl alcohol; lastly, adding zinc powder and hydrogen peroxide solution into acquired 4,4'-dinitrobenzene methyl alcohol, performing centrifugal separation, distilling and drying, thereby acquiring 4,4'-diaminodiphenylmethane. The embodiment proves that the method has a certain universality, the reaction is mild, the technique is simple, the requirement for production equipment is low and the yield of prepared 4,4'-diaminodiphenylmethane reaches more than or equal to 85%.
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Paragraph 0014
(2017/01/17)
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- Cage-to-Cage Cascade Transformations
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A series of Pd2L4-type binuclear self-assembled coordination cages (1–4), where L stands for a nonchelating bidentate ligand, were prepared. The strategies adopted for the synthesis of the cages were: combination of PdIIwith 1) a selected ligand or 2) subcomponents of the ligand. Highly efficient cage-to-cage transformation reactions are demonstrated by suitable covalent modification (from 1 to 2 or 3 or 4) or ligand-exchange reactions (from 1 to 2 or 3 or 4; from 2 to 3 or 4). Thus, new cascade transformations (from 1 to 2 to 3; from 1 to 2 to 4) are achieved beautifully.
- Bandi, Sreenivasulu,Chand, Dillip Kumar
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supporting information
p. 10330 - 10335
(2016/07/21)
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- For the preparation of diamino diphenyl alkane method
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The invention relates to a method for producing diaminodiphenyl alkanes, wherein an aromatic amine, which can be substituted or unsubstituted, is reacted with a C1-C3 aldehyde in the presence of a heterogeneous catalyst, said catalyst being a mesoporous acidic ion exchanger based on a divinylbenzene/styrene copolymer and the catalyst having acid centers in a concentration of 2 to 6 eq/kg measured according to DIN 54403 and the average pore diameter of the catalyst particles being 10 to 32 nm measured according to ASTM D 4222, and the content of polynuclear compounds in the reaction mixture being >10 and ?15% by weight.
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Paragraph 0056-0060
(2017/03/17)
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- HCV NS5A replication complex inhibitors. Part 3
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In a recent disclosure,1 we described the discovery of dimeric, prolinamide-based NS5A replication complex inhibitors exhibiting excellent potency towards an HCV genotype 1b replicon. That disclosure dealt with the SAR exploration of the peripheral region of our lead chemotype, and herein is described the SAR uncovered from a complementary effort that focused on the central core region. From this effort, the contribution of the core region to the overall topology of the pharmacophore, primarily vector orientation and planarity, was determined, with a set of analogs exhibiting 50 in a genotype 1b replicon assay.
- Lopez, Omar D.,Nguyen, Van N.,St. Laurent, Denis R.,Belema, Makonen,Serrano-Wu, Michael H.,Goodrich, Jason T.,Yang, Fukang,Qiu, Yuping,Ripka, Amy S.,Nower, Peter T.,Valera, Lourdes,Liu, Mengping,O'Boyle II, Donald R.,Sun, Jin-Hua,Fridell, Robert A.,Lemm, Julie A.,Gao, Min,Good, Andrew C.,Meanwell, Nicholas A.,Snyder, Lawrence B.
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p. 779 - 784
(2013/02/25)
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- Synthesis, DNA binding and antileishmanial activity of low molecular weight bis-arylimidamides
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The effects of reducing the molecular weight of the antileishmanial compound DB766 on DNA binding affinity, antileishmanial activity and cytotoxicity are reported. The bis-arylimidamides were prepared by the coupling of aryl S-(2-naphthylmethyl)thioimidates with the corresponding amines. Specifically, we have prepared new series of bis-arylimidamides which include 3a, 3b, 6, 9a, 9b, 9c, 13, and 18. Three compounds 9a, 9c, and 18 bind to DNA with similar or moderately lower affinity to that of DB766, the rest of these compounds either show quite weak binding or no binding at all to DNA. Compounds 9a, 9c, and 13 were the most active against Leishmania amazonensis showing IC50 values of less than 1 μM, so they were screened against intracellular Leishmania donovani, showing outstanding activity with IC 50 values of 25-79 nM. Despite exhibiting little in vitro cytotoxicity these three compounds were quite toxic to mice.
- Banerjee, Moloy,Farahat, Abdelbasset A.,Kumar, Arvind,Wenzler, Tanja,Brun, Reto,Munde, Manoj M.,Wilson, W. David,Zhu, Xiaohua,Werbovetz, Karl A.,Boykin, David W.
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p. 449 - 454
(2012/11/07)
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- Synthetic approaches to obtain amino acid adducts of 4,4′- methylenediphenyl diisocyanate
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4,4′-Methylenediphenyl diisocyanate (MDI) is the most important isocyanate used in the chemical industry. Lung sensitization and asthma are the main types of damage after exposure to MDI. Albumin adducts of MDI might be involved in the etiology of sensitization reactions. It is therefore necessary to have sensitive and specific biomarkers such as blood protein adducts to monitor people exposed to isocyanates. For the discovery of new isocyanate adducts with blood proteins present in vivo, new synthetic standards are needed. To achieve this, we developed five methods to obtain amino acid adducts of MDI. We synthesized and isolated MDI adducts of aspartic acid, glutamic acid, cysteine, and valine. The new adducts were characterized by LC-MS/MS and NMR. We synthesized the corresponding isotope-labeled MDI adducts to develop analytical methods using LC-MS/MS. Glutathione adducts of isocyanates are an important way of transportation of the reactive isocyanates to distant sites from the original site of exposure. Therefore, we used N-acetyl-cysteine adducts of MDI as reactants: N-acetyl-S-[[4-(4-aminobenzyl)phenyl]carbamoyl]-cysteine (MDI-AcCys) and N-acetyl-S-[[4-(4-acetylaminobenzyl)phenyl]carbamoyl]-cysteine (AcMDI-AcCys). MDI-AcCys or AcMDI-AcCys formed adducts with albumin, N α-acetyl lysine, and valine. Isotope-labeled albumin adducts (= d4-MDI-albumin) were synthesized from d4-MDI-AcCys and albumin. d4-MDI-albumin can be used as an internal standard to analyze biological samples. Such an internal standard will not correct only for the extraction recovery of the adducts but also for the potential variation of the enzymatic digestions used in the procedure to analyze albumin adducts of MDI. The synthetic procedures described in this manuscript will be applicable to the synthesis of amino acid adducts from other isocyanates.
- Sabbioni, Gabriele,Dongari, Nagaraju,Schneider, Siegfried,Kumar, Anoop
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p. 2704 - 2714
(2013/02/23)
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- Insights on the mechanism for synthesis of methylenedianiline from aniline and formaldehyde through HPLC-MS and isotope tracer studies
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The mechanism for synthesis of 4,4-methylenedianiline (MDA) via condensation reaction of aniline with formaldehyde has been studied extensively in this paper. The intermediate and by-products were isolated and identified. The combination of isotope labeli
- Wang, Chen Ye,Li, Hui Quan,Wang, Li Guo,Cao, Yan,Liu, Hai Tao,Zhang, Yi
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p. 1254 - 1258
(2013/01/15)
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- LOW CHLORINE, MULTI-STAGED METHOD FOR PRODUCING CYCLOALIPHATIC DISOCYANATES
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Low chlorine, multi-staged method for producing cycloaliphatic diisocyanates. The invention relates to a multi-staged method for the continuous low-chlorine production of cycloaliphatic diisocyanates, comprising the synthesis of diaminodipheynl alkanes, the hydration thereof into the corresponding cycloaliphatic diamines and the subsequent conversion of cycloaliphatic diamines to the corresponding cycloalkylene biscarbamates and the thermal cleaving of the latter into the cycloaliphatic diisocyanates and alcohol.
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Page/Page column 14
(2011/02/25)
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- Method of preparing polymethylene-polyphenyl-polyamine
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The present invention provides a method of preparing polymethylene-polyphenyl-polyamine (briefly referred to as polyamine, DAM), in which a high gravity rotating bed is used as the mixing reactor of formaldehyde and aniline hydrochloride, the mixing solution of aniline hydrochloride and circulation solution and the formaldehyde are fed into the high gravity rotating bed reactor proportionally to carry out mixing and condensation reaction under a condition of a very high gravity; the materials leaving the high gravity rotating bed reactor is introduced into a stirred vessel to proceed with the pre-condensation reaction and obtain a condensation solution; and the process steps of heating, molecular rearrangement, neutralization, water washing and purification, etc. are completed to obtain the refined DAM. With the method according to the present invention, the main by-products is obviously reduced in the condensation process, the phenomenon of deposit attaching to the inner walls of circulation pipes and heat exchanger and blockage are prevented in the condensation process, the impurity content is low in the refined DAM, and the subsequent product MDI has a lighter color, the product quality is stable and may be improved to a certain extent.
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Page/Page column 8-9; 11
(2011/04/13)
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- PROCESS FOR PREPARING POLYAROMATIC POLYISOCYANATE COMPOSITIONS
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Process for the preparation of polyaromatic polyamines comprising the step of reacting formaldehyde with at least one monoaromatic monoamine and at least one monoaromatic compound containing at least two amino functions in the presence of an acidic catalyst where a) the total amount of di-aromatic compounds in the polyaromatic polyamine mixture is in the range from about 25 wt % to about 50 wt % and b) the amount of monoaromatic compound containing at least two amine functions is in the range 5 to 30 mole % relative to 100 mole % of the total amount of monoaromatic monoamines and c) the amount of acidic catalyst used in the preparation of the polyaromatic polyamine mixture is less than about 0.4 moles per mole of formaldehyde or formaldehyde equivalents.
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Page/Page column 7-8
(2011/08/08)
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- PROCESS FOR PREPARING DIPHENYLMETHANEDIAMINE
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The invention provides a process for preparing diphenylmethanediamine, comprising the steps of a) reacting aniline with formaldehyde in the presence of an acid,b) neutralizing the acid with ammonia,c) separating the reaction mixture from step b) into an aqueous phase and an organic phase,d) treating the aqueous phase obtained in step c) with an oxide or hydroxide of an alkaline earth metal,e) separating off the ammonia obtained in step d).
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Page/Page column 2-3
(2010/05/13)
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- PROCESS FOR PRODUCTION OF METHYLENE-BRIDGED POLYPHENYL POLYAMINES
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A process for providing methylene-bridged polyphenyl polyamines from aniline and formaldehyde according to the invention comprises the subsequent steps of a) condensing aniline and formaldehyde, providing a condensate, the molar ratio of aniline to formaldehyde being chosen in the range of 2 to 3.5; b) reacting, in a first catalytic reaction step, at a reaction temperature within the range of about 30°C to about 100°C, said condensate over a solid catalyst being chosen from the group consisting of clays, silicates, silica-aluminas and ion exchange resins, whereby an intermediate mixture is provided, the intermediate mixture comprising amino benzyl amines; c) converting, in a subsequent catalytic reaction step, at a temperature within the range of about 70°C to about 250°C, the reaction temperature in said subsequent catalytic reaction step is higher than the reaction temperature in said first catalytic reaction step, said intermediate mixture into methylene-bridged polyphenyl polyamines in presence of a subsequent solid catalyst being chosen from the group consisting of zeolites, delaminated zeolites and ordered mesoporous materials, thereby providing said methylene-bridged polyphenyl polyamines.
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Page/Page column 14-15
(2010/07/09)
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- PRODUCTION OF MIXTURES OF METHYLENEDIANILINE AND ITS HIGHER HOMOLOGUES USING CALCINED METAL OXIDE-SILICA CATALYSTS
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The present disclosure relates to compositions, systems, and methods of forming an amine (e.g., methylenedianiline (MDA)) using an acid catalyst including, for example, a metal oxide-silica catalyst calcined at temperature(s) of about ≥ 500°C to form a solid acid silica-metal oxide catalyst. A metal oxide of a solid acid silica-metal oxide catalyst may comprise alumina. A process for making a solid acid silica-metal oxide catalyst may comprise calcining an amorphous alumina-silica material at temperature(s) of about ≥ 500°C and/or under an anhydrous and/or inert atmosphere. A rearrangement reaction of the condensation product of aniline and formaldehyde in the presence of a solid acid silica-metal oxide catalyst may yield more MDA and/or more desirable isomer(s) of MDA than reactions performed with a corresponding catalyst calcined at temperature(s) of less than 500°C.
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Page/Page column 18; 19
(2010/04/03)
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- A PROCESS FOR PREPARATION OF POLYMETHYLENE POLYPHENYL POLYAMINE
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The present invention provides a method of preparing polymethylene-polyphenyl-polyamine (briefly referred to as polyamine, DAM), in which a high gravity rotating bed is used as the mixing reactor of formaldehyde and aniline hydrochloride, the mixing solution of aniline hydrochloride and circulation solution and the formaldehyde are fed into the high gravity rotating bed reactor proportionally to carry out mixing and condensation reaction under a condition of a very high gravity; the materials leaving the high gravity rotating bed reactor is introduced into a stirred vessel to proceed with the pre-condensation reaction and obtain a condensation solution; and the process steps of heating, molecular rearrangement, neutralization, water washing and purification, etc. are completed to obtain the refined DAM. With the method according to the present invention, the main by-products is obviously reduced in the condensation process, the phenomenon of deposit attaching to the inner walls of circulation pipes and heat exchange and blockage are prevented in the condensation process, the impurity content is low in the refined DAM, and the subsequent product MDI has a lighter color, the product quality is stable and may be improved to a certain extent.
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Page/Page column 6
(2010/02/17)
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- METHOD FOR PRODUCING DIAMINODIPHENYL ALKANES
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The invention relates to a method for producing diaminodiphenyl alkanes, wherein an aromatic amine, which can be substituted or unsubstituted, is reacted with a C1-C3 aldehyde in the presence of a heterogeneous catalyst, said catalyst being a mesoporous acidic ion exchanger based on a divinylbenzene/styrene copolymer and the catalyst having acid centers in a concentration of 4 to 6 eq/kg as measured according to DIN 54 403 and the average pore diameter of the catalyst particles being 10 to 32 nm as measured according to ASTM D 4222 10, and the content of polynuclear compounds in the reaction mixture being ≦10% by weight.
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Page/Page column 3; 4
(2010/12/29)
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- PROCESS FOR PRODUCING DIAMINES AND POLYAMINES OF THE DIPHENYLMETHANE SERIES
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The present invention relates to a process for producing diamines and polyamines of the diphenylmethane series (MDA) by reacting aniline and formaldehyde in the presence of an acid catalyst, wherein the aniline contains in total less than 0.5 wt. %, based on the total weight of aniline, of one or more compounds which contain at least one carbonyl group or of one or more compounds that are formed by reaction of these compounds which contain at least one carbonyl group with aniline.
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Page/Page column 6
(2009/10/01)
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- Synthetic and mechanistic aspects of acid-catalyzed disproportionation of dialkyl diarylmethyl ethers: A combined experimental and theoretical study
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The disproportionation reactions of various dialkyl diarylmethyl ethers have been carried out in the presence of a catalytic amount (10 mol-%) of o-benzenedisulfonimide as a Bronsted acid catalyst; the reaction conditions were mild, and the yields of the diarylmethane target products were good. The catalyst was easily recovered and purified, ready to be used in further reactions. The theoretical study confirmed that the reaction proceeds in two steps: The formation of a carbocation from the protonated ether followed by hydride transfer. Although the hydride transfer is the rate-determining step, it is the stability of the carbocation that determines the reaction rate and therefore the yields.
- Barbero, Margherita,Bazzi, Stefano,Cadamuro, Silvano,Dughera, Stefano,Ghigo, Giovanni
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experimental part
p. 4346 - 4351
(2011/02/24)
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- Functionalized Photoreactive Compounds
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The present invention concerns functionalized photoreactive compounds of formula (I), that are particularly useful in materials for the alignment of liquid crystals. Due to the adjunction of an electron withdrawing group to specific molecular systems bearing an unsaturation directly attached to two unsaturated ring systems, exceptionally high photosensitivities, excellent alignment properties as well as good mechanical robustness could be achieved in materials comprising said functionalized photoreactive compounds of the invention.
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- Process for the production of 4,4'-diphenylmethane diisocyanate
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The present invention relates to a process for the production of 4,4′-diphenylmethane diisocyanate (4,4′-MDI) by acid-catalyzed condensation of aniline with formaldehyde, reaction of the mixtures of di- and polyamines obtained with phosgene to form the corresponding mixture of MDI isomers and homologues (di- and polyisocyanates of the diphenylmethane series) and subsequent separation of the mixture by distillation to form 4,4′-MDI and polymeric MDI.
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Page/Page column 3; 4
(2008/06/13)
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- Process for the production of isocyanates
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Isocyanates, preferably diisocyanates and polyisocyanates of the diphenylmethane series (MDI), are produced by reaction of amines dissolved in a solvent with phosgene in the same solvent to form the corresponding isocyanates. Hydrogen chloride and excess phosgene are subsequently removed from the reaction mixture to obtain a crude isocyanate-containing solution. Subsequently, the crude isocyanate-containing solution is separated by distillation into isocyanates and solvent. The solvent is recycled and used for the production of solutions of the amines and of phosgene. The solvent being recycled is treated to reduce the phosgene and diisocyanate contents before being used for the production of the solution of the amine.
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Page/Page column 4
(2008/06/13)
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- Process for the preparation of 4,4'-diphenylmethane diisocyanate
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4,4'-diphenylmethane diisocyanate is produced at two different sites by a) reacting aniline and formaldehyde in the presence of an acid catalyst to produce a mixture of diamines and polyamines of the diphenylmethane series at a first production site, b) these diamines and polyamines are then reacted with phosgene to give the corresponding diisocyanates and polyisocyanates of the diphenylmethane series, which may optionally be separated by distillation to give a mixture of diisocyanates and polyisocyanates containing from 50 to 80 wt.% of 4,4'-diphenylmethane diisocyanate, from 1 to 12 wt.% of 2,4'- and/or 2,2'-diphenylmethane diisocyanate taken together, and from 10 to 45 wt.% of trifunctional and higher-functional polyisocyanates, based on the weight of the mixture of diisocyanates and polyisocyanates, c) transferring the mixture of diisocyanates and polyisocyanates to transport containers and transporting these isocyanate-containing containers to a second production site remote from the first, and d) separating the mixture of diisocyanates and polyisocyanates by distillation and/or crystallization to give a pure 4,4'-diphenylmethane diisocyanate containing at least 97 wt.% of 4,4'-diphenylmethane diisocyanate and a maximum of 3 wt.% of 2,4'-diphenylmethane diisocyanate.
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Page/Page column 5-6
(2008/06/13)
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- Palladium-catalyzed silane/siloxane reductions in the one-pot conversion of nitro compounds into their amines, hydroxylamines, amides, sulfonamides, and carbamates
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A combination of palladium(II) acetate, aqueous potassium fluoride, and polymethylhydrosiloxane (PMHS) facilitates the room-temperature reduction of aromatic nitro compounds to anilines. These reactions tend to be quick (30 min), high-yielding, and tolerate a range of other functional groups. Replacement of PMHS/KF with triethylsilane allows for the reduction of aliphatic nitro compounds to their corresponding hydroxylamines. Depending on the substrate, both conditions can allow for the in situ conversion of the product amines into amides, sulfonamides, and carbamates. Georg Thieme Verlag Stuttgart.
- Rahaim Jr., Ronald J.,Maleczka Jr., Robert E.
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p. 3316 - 3340
(2008/09/17)
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- Process for the production of di-and polyamines of the diphenylmethane series
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Di- and polyamines of the diphenylmethane series are produced by a) converting nitrobenzene and methanol in the presence of a catalyst to aniline, formaldehyde and carbon monoxide, and then b) converting the aniline and formaldehyde produced in step a) in the presence of an acid catalyst to di- and polyamines of the diphenylmethane series, and c) converting the carbon monoxide produced in step a) with chlorine to phosgene.
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Page/Page column 4
(2008/06/13)
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- Process for the preparation of (poly)-methylenedi(phenylamine)
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Preparation of di- and polyamine of diphenylmethane comprises: (A) mixing a first portion of aniline with an acid catalyst; (B) mixing a second portion of aniline with formaldehyde; and (C) mixing and subsequently reacting the obtained mixtures.
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Page/Page column 5-9
(2008/06/13)
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- Pd-catalyzed silicon hydride reductions of aromatic and aliphatic nitro groups
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(Chemical Equation Presented) Room-temperature reduction of aromatic nitro groups to amines can be accomplished in high yield, with wide functional group tolerance and short reaction times (30 min) using a combination of palladium(II) acetate, aqueous potassium fluoride, and polymethylhydrosiloxane (PMHS). Replacing PMHS/KF with triethylsilane allows aliphatic nitro groups to be reduced to their hydroxylamines.
- Rahaim Jr., Ronald J.,Maleczka Jr., Robert E.
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p. 5087 - 5090
(2007/10/03)
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- METHOD FOR THE PRODUCTION OF AMINES FROM COMPOUNDS COMPRISING CARBODIIMIDE GROUPS, BY HYDROLYSIS WITH WATER
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The invention relates to a single or multiple-step method for the production of monoamines, diamines and/or polyamines from carbodiimide groups and, optionally, also other groups of compounds comprising isocyanate chemicals, by hydrolysis with water.
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Page/Page column 6; 7
(2008/06/13)
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- Stopped-flow kinetic investigations of one-electron transfer reactions of 4,4′-diaminodiphenylmethane and its radical cation in aqueous solution
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The oxidation of 4,4′-diaminodiphenylmethane (DADPM) by metal ion (Ce4+); oxoanions [MnO4- and Cr 2O72-], peroxides [peroxomonosulfate (PMS), peroxodisulfate (PDS) and H2O2], and halogens [Cl 2, Br2 and I2], to the radical cation DADPM?+, and further oxidation to the product monocation DADPM+ by the above mentioned oxidants has been investigated by stopped-flow technique. A probable mechanism has been proposed. The reactions follow a total second-order kinetics, first-order each with respect to the [DADPM] or [DADPM?+] and [oxidant]. In addition, the radical cation DADPM?+ oxidizes sulfite (SO32-), thiosulfate (S2O32-), dithionite (S 2O42-) and metabisulfite (S2O 52-) to regenerate the parent compound DADPM. The rate constants for these reactions have also been estimated. Reactivity for the formation of DADPM follows the decreasing order in the case of oxoanions (MnO4- > Cr2O72- > Ce(IV)) and peroxides (S2O82- > HSO 5- > H2O2) which is in agreement with the redox potentials, while the reactivity trend for halogens is found to be I2 > Br2 > Cl2 which is not in agreement with the redox potentials. The observed rate constants for electron transfer have been correlated theoretically using Marcus theory.
- Sankar,Aravindan,Anandan,Maruthamuthu
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p. 2218 - 2227
(2007/10/03)
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- Photoactive materials applicable to imaging systems
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Organic photoprecursors of amines are provided for use in photosensitive imaging systems, finding particular application in the preparation of lithographic printing plates. Said photoprecursors generate free amines on exposure to long wavelength UV or visible radiation, have high solubility in organic solvents, and include photolabile 2-nitrobenzyl functional groups. Methods for the synthesis of the photoprecursors are described, and the use of the said photoprecursors for the production of printing plates using both positive working and negative working techniques are discussed.
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Page column 13
(2010/02/05)
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- Indium Mediated Reduction of Nitro and Azide Groups in the Presence of HCl in Aqueous Media
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Indium mediated reduction of azide and nitro groups in the presence of HCl (1.5 equiv based on indium) at room temperature in aqueous THF successfully provided the corresponding amine in high to quantitative yields. Under the some reaction conditions, selective reduction of azide and nitro group in the presence of vinyl group could be accomplished.
- Lee, Jung Gyu,Choi, Kyung Il,Koh, Hun Yeong,Kim, Youseung,Kang, Yonghan,Cho, Yong Seo
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- Chiral polyesters with azobenzene moieties in the main chain, synthesis and evaluation of nonlinear optical properties
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The synthesis, characterization and evaluation of nonlinear optical properties of a new series of chiral copolyesters containing push-pull electronic azobenzene mesogenic groups in the main chain are reported. The copolyesters showed liquid crystalline behaviour with high glass transition temperatures (~200 °C), stable liquid crystalline mesophases (up to 360 °C) and high second harmonic generation (SHG) efficiency. The second order nonlinear susceptibility values were measured as a function of the percentage of the chiral building unit and the temporal stability was found to be significant over a long duration of time.
- Bahulayan, Damodaran,Sreekumar, Krishnapillai
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p. 1425 - 1429
(2007/10/03)
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- A Novel and Convenient Route to (1H-1,2,4-Triazol-1-ylmethyl)phenols, Anilines, N-Alkylanilines and N,N-Dialkylanilines
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Phenols, naphthols, anilines, N-alkylanilines and N,N-dialkylanilines are readily alkylated by 1-hydroxymethyl-1,2,4-triazole to afford the corresponding triazole derivatives in good yields.
- Katritzky, Alan R.,El-Zemity, Saad,Lang, Hengyuan
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p. 1813 - 1822
(2007/10/02)
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- Synthesis of phthalonitrile resins containing ether and imide linkages
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Imide-containing phthalonitrile monomers are prepared from a phthalonitrile and an aromatic dianhydride. The monomer and a method for preparing the monomer is disclosed. These monomers are synthesized into heat resistant polymers and copolymers with aromatic ring structure incorporating imide and ether linkages. The synthesis of the high temperature thermosetting polymers and copolymers is also disclosed.
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- Process for the preparation of fluoroaromatic and fluoroheteroaromatic compounds
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Good yields of a range of fluoroaromatic and fluoroheteroaromatic compounds may be obtained by reacting an aromatic or a heteroaromatic amine with a nitrosyl polyfluoro salt in an inert solvent to form an intermediate aryl or heteroaryl diazonium polyfluoro salt and decomposing this aryl or heteroaryl diazonium polyfluoro salt in situ. The process described is especially suitable for the preparation in good yield of fluoroaromatic and fluoroheteroaromatic compounds with ortho substituents.
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- 2-Propanol derivatives as corrosion inhibitors
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New composition comprises a functional fluid in contact with ferrous metal and a corrosion inhibiting amount of at least one compound of formula (I) STR1 or a derivative thereof in which R1, R2 and R3 are, independently, hydrogen, a C1 -C15 straight or branched chain alkyl residue, a C5 -C12 cycloalkyl residue, a C6 -C15 aryl residue or C7 -C12 alkaryl residue, and R4 and R5 are, independently, hydrogen, 2-hydroxyethyl or 2-hydroxypropyl with the provisos that (a) R4 and R5 are not simultaneously hydrogen, (b) when R4 and R5 are each --CH2 --CH2 --OH, R1 and R2 are not simultaneously hydrogen and R3 is not a pentyl residue and (c) that polyalkylene and phenol or polycarboxylic ester co-additives are absent; as well as salts thereof. Some of the compounds of formula I are new.
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- Corrosion inhibiting composition
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A composition, in contact with a corrodable metal surface, which composition comprises: (a) an aqueous-based or oil-based system; and (b) as inhibitor for protecting the metal surface against corrosion, at least one compound having the formula I: STR1 as well as salts or partial esters thereof wherein: n is 0 or an integer ranging from 1 to 20, R is a straight or branched chain C4 -C30 alkyl group, optionally interrupted by one, two or three oxygen atoms or substituted by one, two or three hydroxy groups, a C5 -C12 cycloalkyl group, a C6 -C10 aryl group optionally substituted by one, two or three C1 -C12 alkyl groups, or a C7 -C13 aralkyl group which is optionally substituted by a hydroxyl group; R1 is H or a straight- or branched chain C1 -C4 alkyl group; R2 is H, a straight or branched chain C1 -C4 alkyl group or CO2 H; R3 is H, a straight or branched chain C1 -C4 alkyl group, --CH2 CO2 H or --CH2 CH2 CO2 H; R4 is H, a straight or branched chain C1 -C4 alkyl group or CO2 H; R5 is H, a straight or branched chain C1 -C4 alkyl group, CH2 CO2 H or CH2 CH2 CO2 H; provided that at least one group R4 must be CO2 H, with the provisio, that compositions comprising an oil-based system and a compound having the formula STR2 wherein R, R1 and R2 are hydrogen or alkyl radicals, having a total from 10 to 38 C-atoms, are excluded.
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- Benzotriazole Mediated Synthesis of Methylenebisanilines
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Methylenebisanilines and methylenebis(N,N-dialkylaniline)s are prepared by the reactions of 1-hydroxymethylbenzotriazole with anilines and with N,N-dialkylanilines under acidic conditions.Isolation of the intermediate 4-(benzotriazol-1-ylmethyl)anilines and the N,N-dialkyl analogues and their reactions with anilines allow the efficient preparation of both symmetrical and unsymmetrical members of both product classes.
- Katritzky, Alan R.,Lan, Xiangfu,Lam, Jamshed N.
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p. 341 - 346
(2007/10/02)
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