固体光气法合成十八烷基异氰酸酯研究

在惰性溶剂介质中，以一般化学品固体光气和十八烷基伯胺为主要原料，采用一步法反应合成十八烷基异氰酸酯。进行了惰性溶剂的筛选，同时考察了物料的配比、反应温度、反应时长对反应的影响。结果表明，以甲苯作为惰性溶剂，十八烷基伯胺和固体光气的摩尔比为1∶0.40，保温反应温度在100℃持续反应1.5 h，在此条件下十八烷基异氰酸酯的产率为94.98%。     

Boc-L-天冬酰胺与正己胺的缩合反应研究

氨基酸因含有氨基、羧基等活性基团,易于对其结构进行调控,是构筑小分子有机凝胶的常用骨架或切块。以天冬酰胺为基本骨架,将羧酸位点与正己胺进行缩合反应,形成酰胺键,是一种良好的凝胶因子中间体。研究了Boc-L-天冬酰胺与正己胺的缩合反应,考查了有机碱、反应溶剂和反应温度对反应的影响。条件优化之后发现使用DCC作为缩合剂,DIPEA提供碱性环境,25℃下在DCM溶剂中反应,反应收率可达74%。合成的目标化合物结构经过¹H NMR表征确认,该工艺条件温和,操作简单,效率高。     

正己酸二乙氨基乙酯的合成及反应动力学

[目的]以正己酸和二乙氨基乙醇为原料,阳离子交换树脂催化合成正己酸二乙氨基乙酯.考察了反应过程的影响因素,测定了动力学数据.[结果]合成工艺条件,n(正己酸):n(二乙氨基乙醇)为2.0:1,催化剂用量为正己酸和二乙氨基乙醇总质量的2%,甲苯用量为正己酸和二乙氨基乙醇总体积的110%,反应温度不超过130℃,反应时间3.0 h,二乙氨基乙醇的转化率达95.6%,催化剂重复使用4次后,二乙氨基乙醇的转化率为92.8%.表观活化能为73.219 kJ/mol,指前因子为1.9323×107L/(mol·min).[结论]阳离子交换树脂具有较好的催化活性和稳定性,该酯化反应对正己酸和二乙氨基乙醇均为一级反应.     

正丁基异氰酸酯合成工艺改进

通过实验对正丁基异氰酸酯的原生产工艺重要参数进行了分析,提出了克服原工艺正丁基异氰酸酯收率偏低的改进方案:适当延长预通光时间,采用合理的低温、高温光化温度.在改进后的工艺条件下,光化反应周期缩短,残渣量减少,光化工序产品收率由原来的80.0%左右提高到92.0%.     

异氰酸酯的封闭反应和解封反应

异氰酸酯是性能活泼的化合物,室温下即可与水及含活泼氢的羟基,胺基等化合物化反应。在某些聚氨酯涂料中,常将聚氨酯中-NCO基封闭起来,使用中在高温下使封闭物解封出-NCO基,与羟基组份反应固化。因此有必要对异氰酸酯的封闭反应和解封反应进行研究。本文用化学分析和红外光谱等方法研究了异氰酸酯的封闭反应和解封反应。使TDI与苯酚在不同温度下反应,用化学方法跟踪-NCO基含量随反应时间的变化,发现在120℃下反应6hr,封闭反应基本完成。将封闭物在120～190℃进行红外测试,发现在130℃开始出现2280cm~(-1)的-NCO基特征红外吸收峰,该峰的强度随温度提高而增强,180℃以上峰强度已变化不大。因此,苯酚封闭异氰酸酯的初始解封温度为130℃,在180℃以上解封反应已趋完全。     

高耐候性节能环境友好型阴极电泳涂料的制备与性能研究

使用胺化丙烯酸树脂、胺化环氧树脂、封闭型异氰酸酯固化剂、乳化剂、中和剂、环境友好型助溶剂、水等经乳化制备出一种阴极电泳乳液。由该阴极电泳乳液制备出的高耐候性节能环境友好型阴极电泳涂料具有较好的耐候和防腐性能。所使用的固化剂是一种低温解封(140℃左右)的封闭型异氰酸酯固化剂,将这种固化剂应用到阴极电泳涂料中可以大大节约能源,减少污染。     

N-烷基-3-吡咯酮类化合物的合成

通过合成正己基、正辛基、苄基3种不同取代基的N 烷基 3 吡咯酮,对N 烷基 3 吡咯酮类化合物的合成方法进行了研究。以胺类化合物为原料,与丙烯酸甲酯进行Michael加成,所得一次加成物再与氯乙酸甲酯反应,其产物在甲醇钠存在下进行Dieckmann环合,最后在酸性条件下脱羧,高收率得到N 正己基 3 吡咯酮,N 正辛基 3 吡咯酮和N 苄基 3 吡咯酮,总收率分别为73%,81%和78%。     

正丁基硫代磷酰三胺的绿色合成工艺

以甲苯为溶剂,硫代磷酰氯与过量的正丁胺进入管式反应器中反应,滤出正丁胺盐酸盐后,滤液进入氨化反应釜,通入氨气进行氨化反应,过滤生成的氯化铵,滤液回收大部分甲苯,再经结晶、过滤、干燥即得最终产物正丁基硫代磷酰三胺,总收率达89.8%。正丁胺盐酸盐则在无水条件下回收得正丁胺甲苯溶液,套用于反应,正丁胺回收率大于95%。该工艺操作简单、产生的三废少、生产成本低、收率高且适合工业化生产。     

光气为酰化剂水中一锅法合成四正丁基脲

本文研究了以二正丁基胺、光气和氢氧化钠为原料,水为溶剂一锅法制备四丁基脲的合成工艺。所得产品纯度达到98．5％,收率达90％以上。该方法反应条件温和、操作方便、后处理简单、成本低,适合工业化生产。     

2-氰基乙基戊胺的合成

以甲苯和正丁醇的混合溶液作溶剂,正戊胺与丙烯腈反应合成2-氰基乙基戊胺;验证了溶剂种类和用量,原料配比,反应温度及时间对正戊胺转化率、2-氰基乙基戊胺选择性、单程总收率的影响;最佳工艺条件为:溶剂为混合溶剂[m(甲苯):m(正丁醇)=2:1],m(溶剂):m(正戊胺)=3.0~4.0,n(丙烯腈):n(正戊胺)=1.0,反应温度为50~60℃,丙烯腈滴加时间50min,保温反应时间100min;单程总收率可达83.6%,产品纯度可达98.0%以上。     

Synthesis and characterization of diethylene glycol monobutyl ether—Blocked diisocyanate crosslinkers

Typically blocked isocyanate systems are used to obtain the performance of two component polyurethane (PU) system in a one-component mixture. In this study four types of isocyanates namely, hexamethylene diisocyanate (HDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI) and toluene diisocyanate (TDI) were blocked with diethylene glycol monobutyl ether (DEGMBE). Elimination of the isocyanate groups and the formation of urethane bonds were studied by FTIR spectroscopy and titration methods. Thermal dissociation of blocked diisocyanates was analyzed by DSC and TGA techniques.     

Thermal analysis of oxime-blocked toluene diisocyanates

Oxime-blocked toluene diisocyanates were synthesized and characterized by infrared spectra, nuclear magnetic resonance spectra, elemental analysis etc. Thermal analyses of blocked isocyanates were done by thermogravimetry. Solubility of blocked isocyanates in various polyols was tested. Formation of isocyanate on heating the blocked isocyanate was identified by gas chromatographic analysis.     

三光气法合成取代苯异氰酸酯

以三光气和取代苯胺为原料,合成10种取代苯异氰酸酯。并且对原料的摩尔比、反应溶剂和引发剂等因素对收率的影响进行了研究,研究表明,当三光气与苯胺的摩尔比为1∶2,引发剂为三乙胺,溶剂为甲苯、1,2-二氯乙烷或者乙酸乙酯,反应时间为3.5~5.5 h的情况下,取代苯异氰酸酯产率为69.7%~92.4%。     

Study on cross-linking agent of a novel one-component API adhesive

The high reactivity and toxicity of isocyanates do not allow their storage and use in one-component system aqueous polymer isocyanate adhesives. Blocked isocyanates are a solution to protect the isocyanate groups by blocking with suitable blocking agent. In order to obtain eco-friendly systems and eliminate the effect of the organic solvents on environment, the blocked isocyanates can be dispersed in water by using external emulsifier by incorporating hydrophilic groups into the backbone. In this work, a series of waterborne blocked polyisocyanate dispersions were prepared by anionic modified process, using polyaryl polyisocyanate (PAPI), 2,4,6-trichlorophenol (TCP), and dimethylol propionic acid. Particle sizes were measured and compared by laser particle sizer and scanning electron microscopy. The structures of aqueous dispersions were characterized by FTIR, ¹H NMR, and ¹³C NMR, and results confirmed that the –NCO groups are effectively blocked by –OH groups. Thermal property was investigated using differential scanning calorimetry; then, kinetic parameters, ΔE, and n were deduced. It was found that the deblocking temperature of aqueous dispersion is about 55?°C. Hydrophilicity was characterized by measuring the water contact angles. The experimental results showed that the contact angle of solvent-borne solution is 68.6°, while that of aqueous dispersion is only 25.2°, which indicated that the hydrophilicity of waterborne TCP-blocked PAPI increases for the introduced hydrophilic group compared with solvent-borne TCP-blocked PAPI. The compressive shear strength was tested to evaluate wood bonding performance of the adhesive.     

双(三正丁基)氧化锡参与的异氰酸酯环三聚反应

研究三种异氰酸酯与双（三正丁基）氧化锡在等摩尔比时的反应。证明相互作用的产物是以缔合形式存在的相应锡的氨基甲酸酯。双（三正丁基）氧化锡碳酸酯,氨基甲酸酯及其在异氰酸酯环三聚反应中水解产物催化活性的研究,证明氨基甲酸酯或它与异氰酸酯相互作用的产物,在双（三正丁基）氧化锡参加下,对三聚过程的催化起决定作用。     

Studies on urethane–allophanate networks based on hydroxyl‐terminated polybutadiene: Modeling of network parameters and correlation to mechanical properties

Hydroxyl‐terminated polybutadiene (HTPB)‐based allophanate–urethane networks were prepared by reacting HTPB with di‐isocyanates, such as toluene–di‐isocyanate (TDI), isophorone–di‐isocyanate (IPDI), and 4,4′‐di(socyanatocyclohexyl)methane (H₁₂MDI) at stoichiometric ratios (r‐values) ranging from 1.0 to 1.5. The networks were characterized for mechanical and swell properties. The network parameters, such as “X,” which is the fraction of urethane groups involved in the allophanate formation, and effective chain length (L_x) were calculated from experimental crosslink density values determined from swell data, using α‐model equations developed by Marsh. Excellent linear correlations were obtained between mechanical properties and the calculated network parameters. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2986–2994, 2006     

异氰酸酯及其发展概述

介绍了国内外异氰酸酯的发展概况和常见的异氰酸酯 ,特别是 MDI、TDI和 PAPI的性质和部分商品 ,并简要介绍了 1万 t/ a MDI建设的基础资料 ,指出了我国异氰酸酯的发展方向与存在的问题。     

稀土固体超强酸SO_4~(2-)/ZrO_2/Ce~(4+)催化合成溴代正辛烷

以稀土固体超强酸SO4 2 -/ZrO2 /Ce4 + 为催化剂 ,氢溴酸和正辛醇为原料 ,合成了溴代正辛烷。最适宜合成条件为 :n(氢溴酸 )∶n(正辛醇 ) =3 6∶1 0 ,催化剂CSZ—Ⅱ〔w(Ce) =2 0 %〕的用量为反应物总质量的 1 6 %,反应时间为 5h ,反应温度 130～ 140℃ ,溴代正辛烷产率可达72 8%,精制产品w(溴代正辛烷 ) >99%。催化剂经再生、重复使用 10次 ,溴代正辛烷产率降至 6 9 9%。用IR、1H NMR等手段对产品进行了确证。     

Flow-modified permittivity of solutions of poly(n-butyl isocyanate) and poly(n-hexyl isocyanate)

The dielectric behaviour of solutions of poly(n-butyl isocyanate) and poly(n-hexyl isocyanate) in flow have been examined, including, for the latter polymer, fractions of differing molecular weight. The data are analysed in terms of established theories for changes in the permittivity of solutions of rigid macromolecules undergoing shear and are critically compared to dielectrically based information obtained from studies of still solutions. Rotational diffusion coefficients and dipole moments have been measured and the influence of heterogeneity in molecular weight on flow-modified permittivity is examined. The results obtained support the view that the theories for the flow-modified permittivity of rigid macromolecules are generally satisfactory in providing rotational diffusion coefficients and resolved dipoles, but that the influence of molecular shape on the effect is not simply obtained when polydisperse material is involved.     

Rigid backbone polymers: 6. Ternary phase relationships of polyisocyanates

The ternary systems poly(n-hexyl isocyanate) (PHIC)/poly-(n-octyl isocyanate) (POIC)/tetrachloroethane (TCE), POIC/polystyrene (PS)/TCE, poly(50% n-butyl + 50% p-anisole-2-ethyl) isocyanate (PBAEIC)/PS/TCE, and POIC/PBAEIC/TCE, were studied by means of cross-polarized light microscopy and proton nuclear magnetic resonance (n.m.r.) observations. The system PHIC/POIC/TCE had a polymer concentration range in which a single anisotropic phase was observed over all polymer/polymer ratios. The system POIC/PBAEIC/TCE suggested a similar behaviour. Lower polymer concentrations exhibited an anisotropic/isotropic biphasic concentration interval, and even lower concentrations produced a single isotropic solution. In the systems POIC/PS/TCE and PBAEIC/PS/TCE a single anisotropic phase existed in the high concentration region only where the amount of PS was negligible. In the presence of substantial amounts of PS the systems were either biphasic or isotropic, depending on the polymer/polymer ratio and the concentration of polymer in TCE. The above is in agreement with Flory's recent theory^1–7 concerning the behaviour of mixtures of rod-like particles and mixtures of rods with flexible coils.