齐鲁石化自主开发丁腈橡胶工艺技术

日前,中国石化齐鲁石化橡胶厂开发的丁腈橡胶工艺技术通过了中国石油化工集团公司专家组的技术评议。该技术具有反应速度快、转化率高、共聚物结构均一等特点,产品性能达到国内同类产品先进水平。该厂自2011年开始自主开发丁腈橡胶聚合制备技术,并与山东齐鲁石化工程有限公司合作开发了《3000t·a-1丁腈橡胶试验装置工艺设计包》,其中独创性设计的脱气系统及回收系统具有     

丁二烯-丙烯腈乳液聚合过程的性能研究

在生产N41丁腈橡胶乳液时,考察了聚合反应单体转化率随反应时间的变化,测定了乳液的粒径、黏度、表面张力和机械稳定性等性能。试验结果表明:随着转化率的升高,乳液的粒径、黏度和表面张力逐渐升高,机械稳定性逐渐降低;当转化率为80%时,乳液的各项性能最佳。     

从GPC图谱探讨兰州石化丁腈橡胶的质量

比较了兰州石化丁腈橡胶N41、N32、N21与国内外同系列NBR的GPC图谱，并结合产品的性能对比，认为兰州石化橡胶能满足市场对橡胶的性能要求。     

N-甲基邻硝基苯胺的研究进展

综述了有关N—甲基邻硝基苯胺的现有合成方法，提出了以邻硝基苯胺为原料，酰化，甲基化，再水解，合成N—甲基邻硝基苯胺的工艺路线。该合成工艺条件温和，路线短，原料的转化率高，产品的纯度高(≥98％以上)，易于工业化生产。     

低门尼黏度氢化丁腈橡胶的制备

用不同牌号的丁腈橡胶(NBR)N 32和N 21加入液体丁腈橡胶(LNBR)以及自由基捕获剂制备低门尼黏度氢化丁腈橡胶(HNBR),考察了制备HNBR的影响因素,并与进口HNBR的性能进行了对比。结果表明,用质量比分别为60/30/10/0.3和40/50/10/0.3的N 32/N 21/LNBR自/由基捕获剂作为加氢基础胶,在铑络合物催化剂的用量为180×10-6、氢化压力为7 MPa、温度为80℃的条件下氢化10h,可获得氢化度大于90%、门尼黏度为70~80的HNBR产品;选择含—NH—的防老剂作自由基捕获剂,有利于提高HNBR的氢化度和降低门尼黏度;所制备的HNBR硫化胶的物理机械性能、耐热老化性能与进口产品相当。     

超导炭黑/WGRT填充NBR性能研究

采用丁腈橡胶N41为基体材料,加了超导炭黑,填充不同含量的胶粉,采取不同硫化工艺,用来研究填充不同量胶粉和硫化工艺对丁腈橡胶N41体积电阻和表面电阻的影响关系,并且研究了不同含量的胶粉对丁腈橡胶N41力学性能的影响。通过2种硫化体系抗静电性能数据的对比,发现DCP硫化橡胶80份时体积电阻和表面电阻最好。     

兰州石化公司丁腈橡胶与同类产品的性能比较

对兰州石化公司丁腈橡胶(NBR)与国内市场销售的NBR的硫化特性、应力-应变性能、耐热老化性能、压缩永久变形、耐磨性和耐油性进行了对比研究.结果表明,兰州石化公司牌号为N 21、N 32、N 41的NBR焦烧时间长,物理机械性能处于中等水平,压缩永久变形小,耐磨性好;N 21和N 41的硫化速率慢,N 32的硫化速率则处于中等水平;N 21和N 32的耐热老化性能处于中等水平,但N 41的耐热老化性能优异;N 21的耐油性能处于中等水平,N 32和N 41的耐油性能优异.     

环保型丁腈橡胶与同系列通用牌号产品的性能比较

对比了环保型丁腈橡胶N 41 E和3308 E与同系列的非环保型丁腈橡胶N 41和3308的门尼黏度、硫化特性、力学性能、耐老化性能及发泡性能。结果表明,丁腈橡胶N 41 E的加工性能优于N 41,发泡性能稍逊于N 41,二者的耐热空气老化性能和硫化特性基本相当;丁腈橡胶3308 E的加工性能和发泡性能优于3308,操作安全性、300%定伸应力、永久变形和耐热空气老化性能则稍逊于3308。     

丁二烯丙烯腈聚合过程中间产物性能研究

采用兰州石化公司生产的丁腈橡胶N41乳液聚合配方,考察了聚合反应单体转化率随反应时间的变化,测定了生胶的结合丙烯腈含量、分子质量及其分布、玻璃化转变温度、微凝胶含量和门尼黏度等性能,结果表明:随着转化率的升高,生胶结合丙烯腈含量降低,耐寒性能变好,门尼黏度、相对分子质量及其分布指数升高,当转化率达到86%时,生胶的门尼黏度达到产品指标上限。     

催化反应精馏法合成DMAC的研究

采用催化反应精馏法,以冰醋酸和二甲胺为原料,在催化剂氯化锌的作用下合成N,N-二甲基乙酰胺（DMAC）。主要考察了催化剂用量、反应温度、原料配比、回流比等因素的影响,确定了最佳工艺条件。结果表明：在优化工艺条件下,冰醋酸的转化率和DMAC的反应收率分别达到97％和96％以上,纯度达到99．9％以上,DMAC收率高且产品质量好。     

高聚合度PVC中试配方的调整

在中试装置中对高聚合度PVC（P4000型）配方进行调整：增加TX99和EHP复合引发剂的用量,添加扩链剂C和第3分散剂（醇解度≥88％聚乙烯醇）,使聚合温度由30℃提高到40℃、聚合时间缩短2h,且提高了转化率,改善了树脂的表观密度。     

BF3催化1-癸烯制备聚α-烯烃合成润滑油基础油

低黏度聚α-烯烃（PAO）合成技术主要为国外所垄断,国内少有研究报道。为了解决这一技术问题,本文以1-癸烯为原料,在1L高压反应釜中进行聚合实验,考察反应压力、反应温度、引发剂、反应时间对转化率及聚合产物组成分布的影响,并以优化后的工艺条件在200L低黏度PAO中试试验装置上进行中试放大试验。结果表明,在反应压力为0.2MPa、反应温度为20℃、催化剂加入量为850g、引发剂加入量685mL（与1-癸烯质量比为0.5%）、反应时间2h的条件下,转化率大于95%,产品关键组分三聚体和四聚体含量大于80%,反应放热量约为6.3×10⁴kJ。以此条件获得的产品100℃运动黏度4.3mm²/s,黏度指数132,-40℃低温动力黏度2318 mm²/s,倾点-60℃,与国外产品主要性能指标相当。     

Continuous dosing of fast initiator during vinyl chloride suspension polymerization: Polymerization rate and PVC properties

Continuous dosing of a fast initiator during the suspension polymerization of vinyl chloride has been carried out in a pilot‐scale reactor. The kinetics course of this polymerization and the particle features of the resulting grains were discussed and compared to the conventional polymerization with the same conversion and maximum reaction rate. It was found for the system used that a suitable dosage trajectory allows the reaction rate to remain constant during polymerization. This decreases the polymerization time up to 53% compared with the conventional suspension polymerization, while the molecular weight distribution and molecular weight of the final grains remained almost unchanged. SEM micrographs revealed that PVC grains prepared using this polymerization process had irregularly shaped, uneven particle surfaces and larger particle sizes. The grains also featured high porosity with loosely aggregated smaller primary particles that led to low levels of residual unreacted monomer. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44079.     

丙烯聚合用BCZ型催化剂的开发

在MgCl2溶解过程中加入内给电子体,开发了一种新型丙烯聚合用BCZ型催化剂,并在5 L聚合釜中进行了本体聚合考核评价,在12 m3小本体工艺装置上进行工业应用试验,在25 kg/h的连续法Innovene气相工艺装置进行中试试验。研究表明:用BCZ型催化剂制备聚丙烯(PP)时,催化剂活性高出国产同类催化剂近50%,氢调敏感性好,同样氢气用量下,PP的熔体流动速率可提高25%左右;所制PP的相对分子质量分布大于7.5,等规指数高;BCZ型催化剂可用于小本体法工艺、连续法气相工艺装置制备均聚和共聚PP。     

Experimental investigation of vinyl chloride polymerization at high conversion—reactor dynamics

A series of suspension polymerizations of vinyl chloride monomer (VCM) was carried out in a 5-L pilot plant reactor over the temperature range, 40–70°C. The reactor pressure and monomer conversion were monitored simultaneously every 7–8 min. The critical conversion X_f, at which the liquid monomer phase is consumed, was considered to occur when the reactor pressure fell to 98% of the vapor pressure of VCM for suspension at the polymerization temperature. The reactor model predictions of pressure are in excellent agreement with the experimental data over the entire conversion and temperature ranges studied. The mechanism of reactor pressure development for VCM suspension polymerization is discussed herein in some detail. For isothermal batch polymerization, the reactor pressure falls in two stages due to the effect of polymer particle morphology on pressure drop. The first stage is due to the volume increase of the vapor phase as a result of volume shrinkage due to conversion of monomer to polymer. The monomer phase is not yet consumed at this stage, but it is trapped in the interstices between primary particles creating a mass transfer resistance; therefore, the reactor pressure drops slowly. The second stage is due to both the volume increase of the vapor phase and to the monomer in the vapor phase diffusing into the polymer phase because of the subsaturation condition with respect to monomer in the polymer phase. The reactor pressure drops dramatically with an increase in monomer conversion at this stage. The present model can be used to predict reactor dynamics during suspension polymerization under varying temperature and pressure conditions.     

Nonisothermal suspension polymerization of vinyl chloride for enhanced productivity

In the present study, a mathematical model is developed to numerically predict nonisothermal batch suspension polymerization of vinyl chloride. Free volume theory was used to consider diffusion‐controlled reactions. Model predictions were validated against field data obtained in a pilot scale stirred tank reactor. Variable temperature trajectory was considered during the course of the reaction to improve productivity by reducing the polymerization time for a certain conversion. Variable temperature during the course of the polymerization was successfully implemented by considering the predefined K value. By using variable temperatures during the course of the reaction, the density of the short branches per 1,000 monomer units as a criterion for structure defect remained relatively unchanged. Maximum reduction in reaction time relative to the isothermal case with the same K value and final conversion was 44% for the best temperature trajectory. J. VINYL ADDIT. TECHNOL., 22:470–478, 2016. © 2015 Society of Plastics Engineers     

Continuous Dosing of a Fast Initiator during Suspension Polymerization of Vinyl Chloride for Enhanced Productivity: Mathematical Modeling and Experimental Study

An adopted mathematical model was developed to reduce the batch time required for the suspension polymerization of vinyl chloride in order to improve the productivity by continuous dosage of a fast initiator during polymerization reaction. The model was accompanied by a particle swarm optimization (PSO) algorithm, so as to optimize the initiator dosage rate during the process for a certain conversion. A pilot scale reactor was employed to verify the mathematical model predictions. This showed that the model predictions are in very good agreement with the experimental data. A proper initiator dosage trajectory during the course of the reaction was obtained in such a way that the reaction rate over the course of polymerization was constant and corresponded to the maximum rate in the conventional case (non-continuous addition of a mild initiator). The maximum reduction in reaction time relative to conventional polymerization for the predefined conversion was 53%. Analyzing the molecular characteristics of the samples showed that the molecular characteristics of the final poly(vinyl chloride) (PVC) product remained relatively unchanged under an optimum initiator dosage trajectory compared with the conventional process.     

BULK POLYMERIZATION OF STYRENE IN A STATIC MIXER

An experimental investigation of thermal bulk polymerization of styrene in a pilot plant will be reported. The plant is composed of a recycle tubular reactor followed by a tubular reactor. The conversion of the pre-polymerization part is in the range of 0 to 60% and at the outlet of the pilot plant up to 96%. Studies on the residence time distribution show plug-flow behaviour for a variety of different conditions with respect to viscosity and density gradient. The polymers obtained are characterized by gel permeation chromatography and compared to commercial products.     

Optimization of the coordination–insertion ring‐opening polymerization of poly(p‐dioxanone) by programmed decreasing reaction temperatures

The optimization of the synthesis of poly(p‐dioxanone), by ring‐opening polymerization with tin II bis(2‐ethylhexanoic acid) as the catalyst, was conducted by a new method in which programmed decreasing reaction temperatures were employed. The results were compared with those obtained for polymerization reactions performed at constant temperatures in the 80–180°C range. In the novel method, the temperature was gradually reduced, as the reaction proceeded, to maintain a maximum polymerization rate and monomer conversion as the monomer was consumed. The experiments performed at constant temperatures confirmed previous reports that the bulk polymerization of 1,4‐dioxan‐2‐one is an equilibrium polymerization reaction. With increasing polymerization temperature, the initial rate of polymerization increased, but the monomer conversion, reaching equilibrium, decreased. High conversions were obtained at low temperatures and long reaction times. Therefore, reducing the reaction temperature, to ensure working conditions that guaranteed the maximum polymerization rate and monomer conversion, could optimize the polymerization process. These conditions were calculated under the assumption of equilibrium polymerization reaction kinetics. With our proposed method, a 71% conversion was achieved in half the time needed when the polymerization was performed at a constant temperature of 120°C. Similarly, a 78% conversion was obtained with our proposed method in only a third of the time employed when the reaction was carried out at a constant temperature of 80°C. Our method guarantees high conversions in shorter times and a gradual reduction of the polymerization temperature. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 659–665, 2005     

Synthesis of syndiotacticity‐rich high molecular weight poly(vinyl alcohol) by suspension polymerization of vinyl pivalate and saponification

Vinyl pivalate (VPi) was suspension‐polymerized to synthesize high molecular weight (HMW) poly(vinyl pivalate) (PVPi) with a high conversion above 95% for a precursor of syndiotacticity‐rich HMW poly(vinyl alcohol) (PVA). Also, the effects of the polymerization conditions on the conversion, molecular weight, and degree of branching (DB) of PVPi and PVA prepared by the saponification of PVPi were investigated. Bulk polymerization was slightly superior to suspension polymerization in increasing the molecular weight of PVA. On the other hand, the latter was absolutely superior to the former in increasing the conversion of the polymer, indicating that the suspension polymerization rate of VPi was faster than that of the bulk one. These effects could be explained by a kinetic order of a 2,2′‐azobis(2,4‐dimethylvaleronitrile) concentration calculated by the initial rate method. Suspension polymerization of VPi at 55°C by controlling various polymerization factors proved to be successful in preparing PVA of HMW [number‐average degree of polymerization (P_n): 8200–10,500], high syndiotactic diad content (58%), and very high yield (ultimate conversion of VPi into PVPi: 94–98%). In the case of the bulk polymerization of VPi at the same conditions, the maximum P_n and conversion of 10,700–11,800 and 32–43% were obtained, respectively. The DB was lower and the P_n was higher with PVA prepared from PVPi polymerized at lower initiator concentrations. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 832–839, 2003