Efficient Acetylation of Alcohols,Phenols, and Amines Catalyzed by Melamine Trisulfonic Acid (MTSA)

Melamine trisulfonic acid (MTSA) was easily prepared by the reaction of melamine with neat chlorosulfonic acid at room temperature. This reagent can be used as an efficient catalyst for the acetylation of alcohols, phenols, and amines with Ac₂O under mild and completely heterogeneous reaction conditions.     

三聚氰胺三聚硫氰酸盐的合成

以三聚氰胺和三聚硫氰酸为原料合成了一种新型含硫三聚氰胺基阻燃剂——三聚氰胺三聚硫氰酸盐(MSA),其结构和热性能经1H NMR,13C NMR,FT-IR,元素分析和TGA表征。确定了合成MSA的最优工艺条件为:去离子水为溶剂,三聚硫氰酸和三聚氰胺摩尔比为1∶1,反应时间为3 h。TGA分析表明:MSA失重5%时,温度为308.8℃,600℃时分解基本完全,残碳率为0.86%。     

三聚氰胺甲醛树脂合成—盐酸的催化作用及对产物稳定性的影响

三聚氰胺 (MA)在含有HCl的水溶液中与甲醛 (FA)进行羟甲基化反应。HCl与MA以等摩尔比结合 ,在反应过程中逐渐析出 ,至反应完毕仍保留半结合量。氢离子浓度对三聚氰胺甲醛树脂 (MF)溶液的稳定性有重要的影响     

高热稳定性三聚氰胺聚磷酸盐的合成

以三聚氰胺和磷酸为原料,以去离子水为溶剂,在杂多酸A催化下,制得改性三聚氰胺磷酸盐(MP);将MP在箱式气氛炉中进行多温度段热缩合反应合成了三聚氰胺聚磷酸盐(MPP),其结构经~(31)P NMR,IR和元素分析表征。通过TG对MPP的热稳定性和成炭性能进行了分析。结果表明:MPP失重1%时温度为372.1℃,失重5%时温度为382.7℃,700℃时残炭率为37.36%。     

阻燃剂MCA的高压法合成工艺研究

以三聚氰胺和氰尿酸为原料,以水为溶剂,考察了高压法合成阻燃剂MCA的工艺。在反应压力为120 KPa、三聚氰胺与氰尿酸的摩尔比约为1∶1.02下,采用改变单一因素的方法探讨了在不同温度、压力、反应时间及不同p H值等情况下对反应结果的影响,得出较优的工艺条件为反应时间为1.5 h、反应的最佳温度为105℃、p H值保持在7左右最佳,在此条件下,产品纯度可达98%以上,产品质量稳定。     

六甲氧基甲基三聚氰胺-多元醇-丙烯酸酯混杂聚合中酸的双重作用

六甲氧基甲基三聚氰胺 (HMMM) 多元醇 丙烯酸酯混合体系在较高温度下可同时进行缩聚和自由基聚合并表现出加速固化、热互补、原位形成高分子合金等协同效应 .通过凝胶化时间和聚合反应速度的研究 ,发现酸既是HMMM 多元醇缩聚反应的催化剂 ,也是促进过氧化氢物分解产生自由基引发丙烯酸酯自由基聚合的催化剂 .研究还发现 ,以潜酸催化剂作为酸的来源可以使体系达到室温稳定 ,高温快速固化的目的     

碳载高分散钯纳米粒子的制备及催化Suzuki反应

利用三聚氰胺甲醛预聚物中N原子与Pd²⁺的相互作用,将Pd²⁺化学锚定在预聚物中;并以二氧化硅水凝胶为造孔剂、2,4-二氨基苯磺酸为预聚物缩合促进剂,在水溶液中制备出锚定了Pd²⁺的胶体纳米球;再经摩尔分数5%氢气焙烧、HF腐蚀,得到Pd质量分数为1.37%、平均粒径为(2.4±0.87) nm的碳载高分散Pd纳米粒子催化剂Pd@C。 将其应用于Suzuki反应,在加入Pd与碘苯物质的量比为1:100的催化剂时,反应5 min收率为99.3%,且经8次循环后活性未降低,表现出良好的催化效果和重复使用性。     

三聚氰胺磁性分子印迹聚合物材料的制备及性能表征

利用溶剂热法通过控制反应时间和温度制得了分散性好和磁性强的Fe3O4,并利用溶胶凝胶法制备得到包覆SiO2的磁性微球(Fe3O4@SiO2)。以三聚氰胺为模板分子,甲基丙烯酸(MAA)为单体,采用本体聚合法制备了磁性分子印迹聚合物(MMIPs)。通过静态吸附实验表明,MMIPs对三聚氰胺的饱和吸附量高达10.22μg/mg,是磁性非印迹聚合物(MNIPs)的1.62倍。粒子扩散模型、Elovich模型和动态吸附实验表明所制得的MMIPs有较好的吸附性能。     

六甲氧基甲基三聚氰胺-多元醇-丙烯酸酯混杂聚合体系的研究

六甲氧基甲基三聚氰胺 (HMMM) 多元醇 丙烯酸酯 酸催化剂混杂聚合体系在高温下同时进行缩聚和自由基聚合并表现出协同效应 .体系中的活泼亚甲基在HMMM的催化下被空气氧化成过氧化氢物 ;过氧化氢物在酸催化下分解成自由基进而引发自由基聚合反应 .研究结果表明 ,体系中存在固化加速的协同效应 ;同时体系中还存在热互补效应 ,丙烯酸酯的自由基聚合反应放出的热可以传递给缩聚反应 ,满足缩聚反应吸热的要求 .混杂聚合得到的高分子合金膜具有优良的机械性能和耐溶剂性能 ,这是由于在混杂聚合过程中形成了互穿聚合物网络 (IPN)结构 .使用潜酸催化剂作为酸的来源 ,可以提高体系的储存稳定性 ;交联 引发剂的使用可以拓宽它的使用范围 ;对超枝化聚合物在混杂体系中的应用也进行了初步研究     

Pd immobilized on polyamide based on melamine and terephalic acid as an efficient and recyclable catalyst for Suzuki‐Miyaura coupling reaction

A simple synthetic strategy of polyamide was described from melamine and terephalic acid via one‐step polycondensation. PdCl₂ was then immobilized on the polyamide (denoted as Pd/MPA). Melamine and terephalic acid not only acted as monomers but also provided the ligand sites to help the polyamide to coordinate with Pd(II). The Pd/MPA catalyst was characterized by FT‐IR, TGA, SEM, TEM, XPS, N₂ adsorption‐desorption and atomic absorption spectroscopy. The catalyst was used in Suzuki‐Miyaura coupling reaction of various aryl halides, including less reactive chlorobenzene and benzyl chloride, to give the coupling products in moderate to excellent yields. High turnover frequencies (TOF) up to 29400 h^‐1 can be also obtained. In addition, it behaved truly as a heterogeneous catalyst with high reusability after being recycled 6 times and palladium leaching was negligible during the process. This work provides a practical polyamide support to develop heterogeneous palladium catalysts with simple synthetic procedure and low cost.     

亲水色谱-串联质谱法对牛奶与奶粉中三聚氰胺及其衍生物含量的测定

建立了牛奶和奶粉中三聚氰胺及其3种衍生物（三聚氰酸、三聚氰酸一酰胺、三聚氰酸二酰胺）的亲水色谱-串联质谱检测方法（HILIC-MS/MS）。牛奶样品直接用乙腈超声波提取;奶粉样品先用水溶解后再加乙腈超声波提取,高速离心后以乙腈-水为流动相,采用亲水作用色谱柱分离这4种化合物,在电喷雾正、负电离切换多反应监测模式下进行定性与定量分析,三聚氰酸一酰胺与三聚氰酸二酰胺含量在50～10000μg/kg之间、三聚氰胺与三聚氰酸在25～5000μg/kg之间,均获得良好的线性。方法检出限（LOD）为5～20μg/kg,定量下限（LOQ）为50～100μg/kg,3个添加水平的平均回收率为81%～97%。该方法简便、快速、准确,可满足牛奶及奶粉中三聚氰胺、三聚氰酸、三聚氰酸一酰胺、三聚氰酸二酰胺测定的需要。     

反应性挤出加工制备无卤阻燃高分子材料

聚合物反应性加工集聚合物加工与化学反应为一体,以聚合物加工装置为反应器,通过聚合物加工过程中的化学反应形成新物质和新结构,实现高分子材料的高性能化和功能化,是高分子材料科学的研究前沿之一.本文简要介绍了我们研究小组近年来采用反应性挤出加工制备高性能无卤阻燃高分子材料方面的研究进展.利用反应性挤出加工剪切力强、温度可控以及易于传质传热的特点实现了常规方法难以合成的高黏阻燃剂三聚氰胺磷酸盐季戊四醇酯（MPP）和三聚氰胺氰尿酸（MCA）的高效合成,制备了综合性能优良的聚丙烯/MPP、尼龙6/MCA等无卤阻燃高分子材料.研究所涉及的化学和物理方法,为聚合物无卤阻燃提供了高效、经济、环保和易于工业化的新技术,并拓宽了聚合物反应性加工的应用领域.     

Synthesis of melamine-glucose resin adhesive

The synthesis of a novel melamine-glucose adhesive that is similar to urea-formaldehyde adhesive is reported in this paper. The conditions of synthesis, such as the initial pH, the quantity of catalyst, the temperature of reaction, the percentage of each reactant and the time of reaction, were optimized by using the orthogonal experimental method.     

Reaction of melamine phosphate with pentaerythritol and its products for flame retardation of polypropylene

Due to being halogen‐free, non‐toxic, non‐erosive and environmentally friendly, melamine‐based flame retardants are attracting more and more attention. As a melamine‐based intumescent flame retardant, in this study the melamine salt of pentaerythritol phosphate (MPP) was prepared from melamine phosphate (MP) and pentaerythritol (PER). The reaction of MP with PER was then systematically investigated. The reaction product MPP was utilized to flame‐retard polypropylene (PP). FT‐IR, TGA and DSC were used to characterize MPP and also to investigate the reaction of MP and PER in depth. The experimental results show that MPP has good thermal stability and matched decomposition temperature with that of PP, making it suitable for flame retarding of PP. Also, MPP is melting‐blendable due to its softening during the heating process. The structure of MPP at a MP:PER molar ratio of 2.0 was confirmed as the same to that of the product synthesized from phosphorus oxychloride, pentaerythritol and melamine. The reaction of MP with PER was greatly influenced by the MP:PER proportion, reaction temperature and reaction time, rather than the physical state of PER, and the reaction mechanism of MP with PER was proposed. The prepared flame‐retarded polypropylene composite with 35 wt% intumescent flame‐retardant MPP has a flame retarding level of 3.2 mm UL 94 V‐0, tensile strength 27.0 MPa, Young's modulus 2442 MPa and Izod notched impact strength 3.8 kJ/m². Copyright © 2007 John Wiley & Sons, Ltd.     

固相萃取-亲水相互作用色谱/串联质谱法同时测定食品中三聚氰胺和三聚氰酸

建立了固相萃取-亲水相互作用色谱/串联质谱同时测定食品中三聚氰胺和三聚氰酸残留量的方法。采用乙腈和水提取试样中残留的三聚氰胺和三聚氰酸,正己烷脱脂,提取液经亲水性键合硅胶和阳离子交换树脂复合填料柱(MCT柱)净化。采用亲水相互作用色谱柱进行分离,质谱采用正、负离子切换模式电离,多反应监测模式检测,同位素内标法定量。三聚氰胺和三聚氰酸在10～2500 μg/L范围内呈线性相关,相关系数(r)均大于0.99,定量限分别为25和50 μg/kg。本方法在动物源性食品、植物源性食品、乳及乳制品等不同样品中的三聚氰胺和三聚氰酸高、中、低3个添加水平的回收率分别在70.0%～129.6%和70.0%～128.6%之间,相对标准偏差分别在1.4%～23.3%和2.8%～18.7%之间。该方法可满足食品中三聚氰胺和三聚氰酸同时定量测定的需要。     

气相色谱-质谱法测定鸡蛋中三聚氰胺

建立了气相色谱-质谱法测定鸡蛋中三聚氰胺的方法. 鸡蛋样品经三氯乙酸提取,乙酸铅沉淀蛋白后,过MCX阳离子交换固相萃取小柱除去样品基质干扰,用N,O-双三甲基硅基三氟乙酰胺(BSTFA)+三甲基氯硅烷(TMCS)(99+1)衍生,进行气相色谱-质谱分析. 在0.010~2.00 mg/L浓度范围内,线性关系良好(r=0.9996),检出限为0.01 mg/kg. 方法回收率为90.1%~94.7%,RSD为1.7%~5.3%. 方法准确、灵敏,适用于鸡蛋中三聚氰胺的检测.     

气相色谱-质谱法快速测定牛奶中的三聚氰胺和三聚氰酸

建立了气相色谱-质谱法测定牛奶中三聚氰胺和三聚氰酸含量的分析方法。样品经二乙胺-乙腈-水溶液超声提取,离心,滤液用氮气吹干后加入硅烷化衍生试剂衍生,气相色谱-质谱测定,选择离子模式监测,外标法定量。在0.025～2 mg/kg范围内,目标物的峰面积与其质量浓度的线性关系良好(r>0.98);在0.5,1.0和2.5 mg/kg的添加水平,三聚氰胺和三聚氰酸的平均回收率分别为84%～87%和75%～102%,相对标准偏差(RSD)分别为5.7%～11.7%和4.9%～7.8%;三聚氰胺和三聚氰酸的检出限(LOD)分别为0.05 mg/kg和0.10 mg/kg。结果表明:该方法简便、快速、灵敏、准确,适合牛奶中三聚氰胺和三聚氰酸的确证和定量测定。     

Convergent Versus Divergent Three-Step Synthesis of the First (4-Aminophenoxy)alkanoic Acid–Based Tripodal Melamines

Starting from N-(4-hydroxyphenyl)acetamide (Paracetamol, convergent approach) or from cyanuric chloride in reaction with 4-aminophenol (divergent approach), two synthetic routes toward novel tripodal N-substituted melamines as s-triazine derivatives of (4-aminophenoxy)acetic acid or of 4-(4-aminophenoxy)butyric acid are comparatively defined. The key steps consist of Williamson etherification of N-masked forms of 4-aminophenol and acidic hydrolysis of the N- and/or O-protected (4-aminophenoxy)alkanoic segments.     

NLO polymers based on cellulose diacetate and a cationic chromophore

An attempt has been made to prepare second-order nonlinear optic (NLO) materials based on cellulose diacetate and melamine derivatives. The NLO cationic chromophore, composed of 1,3-dimethyl-2-(4′-N,N-dimethylaminophenyl)-azo-imidazole chloride and small amounts of 1,3-dimethyl-2-(4′-N,N-dimethylaminophenyl)-azo-imidazole methylsulfate, was incorporated into a crosslink network formed from the reaction of cellulose diacetate with trimethylol melamine or hexamethylol melamine. The poled and cured NLO materials exhibited an electro-optic coefficient (r ₁₃) of 1.03 or 1.42 pm/V, respectively, at the laser wavelength 1550 nm and a modulation frequency of 12.7 kHz; the r ₁₃ values decreased to 97% or 86.6%, respectively, of the initial values after 4 days. The laser transmission loss was 0.58 or 0.6 dB, respectively. The crosslinked materials showed better temporal stability than the material of the host/guest system with a doped cationic chromophore. The results of Fourier transform infrared spectroscopy, dielectric relaxation and thermogravimetry analyses proved the formation of a crosslink structure, and the degree of dielectric relaxation was shown to became higher if a crosslinker of too high functionality was used.     

The Reaction Mechanism of the Transetherification and Crosslinking of Melamine Resins

Melamine formaldehyde resins (MFR) are well known resins in the wood board and paper coating market. Etherified MFR's are applied as crosslinkers in the automotive coating industry. In Europe the growth of the market and the research activities are relatively small. On the other side in comparison to other polymers outstanding properties are possible to realize. So the development of new melamine ether resins (MER) was started. MER is a partly methylolated and fully etherified resin with a highly stable “thermoplastic” processing range. The MER's themselves are transparent granulates with enough stability for storage and transport. The crosslinking reaction can be started either by thermal or acidic catalytic activation, without losses of formaldehyde. Transetherifications with oligomeric diols can lead to more elastic and higher molecular melamine polyether resin (MPER) structures. The reaction mechanism and the crosslinking kinetics of the partly methylolated melamine ethers of methanol in comparison to the fully methylolated hexamethylol melamine ether will be discussed in this paper.