混合溶剂制备溶油性减阻剂的研究

依据溶度参数理论和分子模拟软件,配制溶度参数各异的混合溶剂,并用混合溶剂合成聚α-烯烃减阻剂。对减阻剂的黏均相对分子质量、加剂浓度与减阻率、混合溶剂的表观黏度的研究结果表明:当混合溶剂的溶度参数逐渐接近聚合物的溶度参数时,其合成出的减阻剂聚合物的相对分子质量与减阻率也随之增大。用一种脂肪烃(正己烷)和一种芳烃(甲苯)配制的混合溶剂除了溶度参数以外还需考虑溶剂的极性。溶度参数理论可以指导混合溶剂的配制。     

聚ɑ-烯烃减阻剂不同溶剂对性能的影响

利用斯摩尔公式分别计算了聚1-12烯、1-辛烯和1-12烯摩尔比为1∶4的共聚物的溶度参数,根据计算结果筛选了它们溶液聚合的良溶剂,通过实验考察了在反应条件一致的情况下,溶度参数不同的溶剂在溶液聚合过程中对聚合物黏均相对分子质量以及减阻率的影响,并对合成出来的减阻剂做了XRD表征。结果表明利用斯摩尔公式计算聚合物的溶度参数进而筛选合适的良溶剂是比较可靠的,可以用来指导今后减阻剂的合成。     

分子模拟在溶液聚合溶剂筛选中的应用

为提高溶液聚合过程中筛选溶剂的效率,采用分子模拟软件分别构建聚1-十二烯、聚1-辛烯以及n(苯乙烯)∶n(1-十二烯)=2∶3的共聚物的结构模型,利用结构平衡后的轨迹数据计算其溶度参数,并依据模拟的结果筛选出溶液聚合的良溶剂,最后通过试验考察了在反应条件一致的情况下,溶度参数不同的溶剂在溶液聚合过程中对聚合物黏均相对分子质量以及结晶性的影响,发现随着溶剂与聚合物的溶度参数越是接近,聚合物黏均相对分子质量越大,结晶性越小。结果表明,用分子模拟软件模拟聚合物的溶度参数进而筛选合适的良溶剂是比较可靠,可以用来指导聚合物的合成。     

极性溶剂E和正庚烷混合脱沥青

华东化工学院石油加工研究所在实验室进行了用极性溶剂E和正庚烷混合对胜利减渣油脱沥青的研究.结果表明: 1.极性溶剂E具有高速率脱沥青的特点.用溶剂E和正庚烷混合溶剂,在常压下间歇操作,溶     

溶度差法计算地层油-CO2体系的最小混相压力

从分子间作用力角度,利用经典溶度理论和PR-EOS状态方程,在油藏条件下推导出地层油的溶度参数计算公式,并结合纯气体溶度计算公式,对不同油藏条件下的地层油-CO2最小混相压力进行理论计算。该方法仅需油藏温度、地层油组分(C1—C3+6)和C3+6分子质量3组参数。研究表明,在分析了中国17个陆相沉积特点地层油的细管测试实验结果基础上,得出地层油-CO2体系达到混相时,两者的溶度差与C3+6组分的分子质量存在较好的线性关系,利用该关系可以反求出地层油-CO2体系达到混相所需的压力,为数值模拟的修正和油藏工程方案设计提供了1种可行的计算方法。     

现代化工分离技术讲座 第八章 富勒烯的分离纯化

(上接2 0 0 3年第6期)2 .1　C60 在有机溶剂中的溶解度一些溶剂参数如折光率(n)、介电常数(ε)、Hildebrand溶度参数(δ)和溶剂的摩尔体积(υ)对C60 的溶解性能影响见表8 1。由表8 1可见,[(n2 - 1 ) /(n2 + 2 ) ]值与[(ε- 1 ) /(ε+ 2 ) ]值越接近的溶剂,C60 在其中的溶解度越大,如甲苯,二硫化碳。由表8 1溶解度数据看出,由于C60 的坚硬结构使其不易溶于一般有机溶剂尤其是极性溶剂和氢键溶剂;C60 在烷烃中的溶解度一般都较低(烷烃的碳数越高,C60 的溶解度越大) ,即便是正十二烷对C60 的溶解度也仅为0 .0 71 g/L ,而在十氢化萘中的溶解…     

α-SAN共聚物的溶度参数及其与ABS、PVC的相容性

溶剂分类法和粘度法相结合测定了α-SAN 共聚物的溶度参数为20.1(J/cm~(?))1/2。实测值与估算值相当一致。根据溶度参数法则推断,α-SAN、PVC 及 ABS 间具有热力学相容性。采用 DSC及扫描电镜测试了共混物的 Tg 和微观结构形态。结果表明,α-SAN 和 PVC 及 ABS 树脂中的 AS 能形成均匀的连续相,是良好的共混材科     

分子模拟助溶剂在硅氧烷类SC-CO2压裂液中的助溶行为研究

超临界二氧化碳压裂液体系由于黏度低，一般选用加入增稠剂的方法来克服携砂效率低的难题。硅氧烷类增稠剂具有低内聚能和良好的增黏性被广泛地选用，但是使用时需要添加助溶剂提高溶解效果。因此，选用被广泛使用的聚二甲基硅氧烷(PDMS)作为研究对象，利用分子模拟研究了甲醇、甲苯和环己烷等助溶剂的加入对聚二甲基硅氧烷在SCCO₂体系中溶解行为的影响。基于溶剂-溶剂和溶剂-溶质的结合能、径向分布函数和内聚能密度等参数，对比分析了极性助溶剂和非极性助溶剂对聚二甲基硅氧烷在超临界二氧化碳压裂液体系中的助溶效果。分子模拟结果表明，在相同助溶剂含量下，甲醇与溶剂体系溶解度参数差值小于0.5，助溶效果优于甲苯和环己烷。结论分析认为，使用助溶剂提高PDMS在SC-CO₂中溶解度的实质是CO₂与PDMS聚合物分子间作用力、CO₂与助溶剂分子间作用力以及PDMS聚合物与助溶剂分子间作用力的平衡。因此，当硅氧烷类增稠剂本身为非极性材料时，推荐采用甲苯作为助溶剂。若硅氧烷类材料具有一定弱极性时，采用甲醇最为适合。     

5—亚硝基—2，4，6—三氨基嘧啶的合成

研究了一种合成5－亚硝基－2,4,6－三氨基嘧啶的改进方法,该法采用二甲基亚砜和二甲苯作为混合溶剂共沸脱水,克服了单一极性溶剂脱水困难的缺点。考察了反应原料摩尔比,亚硝化湿度、反应时间以及混合溶剂比例和用量对产品收率的影响,并确定了合成的最佳条件。     

化学工程

TQ013.1200608416甲烷在烃类混合溶剂中高压溶解度的测定〔刊〕/郭玉高,马沛生…(天津大学化工学院)∥天津大学学报.-2005,38(11).-960~965选择环己烷-苯、正庚烷-环己烷和苯-正庚烷混合溶液作为溶剂,用自建的循环法测定气体高压溶解度实验装置,测定了甲烷在上述溶剂中的高压溶解度数据。用Peng-Robin-son状态方程计算实验数据,发现对于非极性的混合溶剂,甲烷的速度与其溶解度成非常好的线性关系;考察了用文献中二元数据和三元数据计算交互作用参数对计算结果的影响。估算结果与实验值能很好吻合。表5参8(刘宁摘)TQ013.1TQ018200608417C…     

1,3-2,4-二对甲基亚苄叉山梨醇在不同溶剂中溶解度的测定

以基团贡献法计算了聚丙烯成核剂MDBS的溶解度参数(δ=27.30 J~(1/2)/cm~(3/2)),在此基础上计算了部分溶剂与1,3-2,4-二对甲基亚苄叉山梨醇(MDBS)试样的相容性参数(P),其中P(MDBS-C_6H_5CH_2OH)=31.89,P(MDBS-C_6 H_5CH_2CH_2OH)=43.47,P(MDBS-1,2-二氧六环)=128.71,苯甲醇为MDBS成核剂的较好溶剂,其次为苯乙醇,再次为1,4-二氧六环。测定了MDBS试样在不同溶剂中的溶解度,并建立了该成核剂试样在不同溶剂中的溶解度与温度的关系方程。结果表明,在相同温度下,MDBS在苯甲醇中溶解度稍大于在苯乙醇中的溶解度;MDBS在1,4-二氧六环中的溶解度小于在苯甲醇、苯乙醇中的溶解度。     

浅谈单溶剂与双溶剂的脱蜡效果

就溶剂脱过程中溶剂的选择进行了论述。通过用甲异丁基酮和甲乙酮混合溶剂做脱蜡或脱油溶剂，对溶解能力，脱后油收率，等性能方面的综合比较，提出了发展ＭＩＢＫ脱蜡工艺的建议。     

二元溶剂萃取分离重油中芳烃的机理

石油重质馏分油中含有多种烃结构组分,如链烷烃、环烷烃以及不同环数芳烃,采用极性溶剂萃取分离工艺可以实现不同组分的分离,但一元溶剂萃取的精制油收率低、芳烃萃取选择性较差。以减压馏分油为原料,糠醛为主溶剂,含羟基的极性调节剂PR1为副溶剂,开展一元溶剂、二元溶剂单段萃取实验,通过对主溶剂溶解度参数的调配,提升溶剂萃取分离不同烃组分的效果。结果表明,与一元溶剂相比,二元溶剂对三环及以上的芳烃萃取选择性提升率超过100%,用一种新的基团贡献法计算了6种模型分子的溶解度参数,发现各芳烃的萃取选择性随芳烃溶解度参数的增大而增大。考察了不同PR1加入量的二元溶剂萃取效果,结合二元溶剂溶解度参数变化与溶剂核磁共振氢谱(¹H-NMR)化学位移变化,发现溶剂体系氢键作用的变化是溶剂萃取效果产生差异的根本原因。     

POLYMER SOLUBILITY THEORY PREDICTS EFFICIENCY OF RESIDUAL OIL EXTRACTION BY POLAR SOLVENTS

Light paraffinic solvents (C2 to C7) have traditionally been utilized by the petroleum refining industry to extract oils from crude distillation residua. Extracted oils constitute feedstock to lubricants manufacture and, to a lesser extent, additional cracking stock. More recent literature reveals a growing interest in polar, non-hydrocarbon partially oil-soluble solvents such as alcohols, ketones, and esters of lower carboxylic acids. In this work, articles and patents which report the separation of residua into asphalt and extracted oil by means of polar solvents are briefly reviewed, and the separation performance of same of those solvents is correlated to the solute-solvent interaction parameter (ϰ) in the Flory-Huggins theory of polymer solubility. The three dimensional solubility parameter (δ) approach is followed to estimate ϰ for the solvents of interest at the appropriate operating conditions. The saturate, aromatic, and polar compounds fractions of a bitumen are characterized by solubility parameters equal to the values of δ of the solvents or mixtures thereof used by the standard ASTM D-2007 chromatographic fractionation of the deasphaltenated oil (DAO). A mean value of ϰ is found for every DAO-solvent pair, treatment ratio and temperature. For each solvent considered, yields of extracted oil at varying operating conditions (temperature, pressure, solvent /feed ratio) are found to be well correlated to ϰ, in according with theoretical predictions that the lower a value of ϰ a solvent has for a given solute, the better it dissolves the solute and the higher the yield.

It is suggested that this type of approach could supply criteria to select solvents and operating conditions for applications requiring high yields (to produce additional cracking stock) or lower yields but high rejection of metals and heteroatoms (e.g. for lube oil bases extraction).     

POLYMER SOLUBILITY THEORY PREDICTS EFFICIENCY OF RESIDUAL OIL EXTRACTION BY POLAR SOLVENTS

ABSTRACT

Light paraffinic solvents (C2 to C7) have traditionally been utilized by the petroleum refining industry to extract oils from crude distillation residua. Extracted oils constitute feedstock to lubricants manufacture and, to a lesser extent, additional cracking stock. More recent literature reveals a growing interest in polar, non-hydrocarbon partially oil-soluble solvents such as alcohols, ketones, and esters of lower carboxylic acids. In this work, articles and patents which report the separation of residua into asphalt and extracted oil by means of polar solvents are briefly reviewed, and the separation performance of same of those solvents is correlated to the solute-solvent interaction parameter (?) in the Flory-Huggins theory of polymer solubility. The three dimensional solubility parameter (δ) approach is followed to estimate ? for the solvents of interest at the appropriate operating conditions. The saturate, aromatic, and polar compounds fractions of a bitumen are characterized by solubility parameters equal to the values of δ of the solvents or mixtures thereof used by the standard ASTM D-2007 chromatographic fractionation of the deasphaltenated oil (DAO). A mean value of ? is found for every DAO-solvent pair, treatment ratio and temperature. For each solvent considered, yields of extracted oil at varying operating conditions (temperature, pressure, solvent /feed ratio) are found to be well correlated to ?, in according with theoretical predictions that the lower a value of ? a solvent has for a given solute, the better it dissolves the solute and the higher the yield.

It is suggested that this type of approach could supply criteria to select solvents and operating conditions for applications requiring high yields (to produce additional cracking stock) or lower yields but high rejection of metals and heteroatoms (e.g. for lube oil bases extraction).     

碳纤维原料沥青的分子量测定

用溶解法对通用级碳纤维用沥青的溶剂进行了筛选，发现三氯代苯可将高软化点沥青彻底溶解。以三氯代苯为溶剂，用ＶＰＯ法测定了４种国产碳纤维级沥青的分子量，所得结果的准确度大大提高。以三氯代苯和正庚烷的混合溶剂对碳纤维沥青进行了分级处理，获得８个不同分子量的沥青级分。     

STUDY OF THE TEMPERATURE AND ENTHALPY OF WAX CRYSTALLIZATION FROM MIDDLE DISTILLATE BY DSC

The temperature and enthalpy of the wax crystallization as well as of melting have been studied in the middle distillate (boiling range: 250-375°C) obtained from the indigenous Bombay-High (Off-Shore) crude oil by using a differential scanning calorimeter (DSC). In order to have better understanding of the gel formation processes the broad distillate fraction was fractionated into five narrow fractions of 25°C interval each. From these narrow subfractions the saturates were separated from aromatics by column chromatography, and from saturates the n-paraffins were separated from iso-and cyclo-paraffins by urea adduction, to obtain the n-paraffins concentrates (urea adductables)--the wax- and the saturated solvent portion--the UNA. The thermal behaviour of narrow subfractions alongwith their urea adductables and the solvent portions have been studied and the wax appearance temperature (WAT) thus measured has been compared with those obtained by optical microscopy and with the ASTM cloud point, wherever possible. To obtain a clearer picture of the solidification process, further study has been done by preparing synthetic blends of urea adductables in different concentrations in the respective aromatic and iso- and cyclo-paraffinic solvents (UNA) and studying the thermal behaviour of each blend. It is found that the variation in WAT with wax concentration as measured by DSC is identical with that measured by optical microscopy and the ASTM cloud point. However, DSC values are lower than microscopic values and higher than ASTM cloud point. The enthalpy of the blends with the same amount of wax in the aromatic and iso- and cyclo-parffinic solvents indicated that it is higher in the saturated solvent in comparison to aromatic solvent. This confirms the fact that in an aromatic solvent the solubility of the wax is greater, and hence a comparatively lower WAT. The results are further discussed.     

CHARACTERIZATION OF HEAVY RESIDUA BY APPLICATION OF A MODIFIED D 2007 AND ASPHALTENE SEPARATION: EFFECT OF SOLVENTS ON PHYSICAL AND CHEMICAL PROPERTIES OF FRACTIONS DERIVED FROM HONDO 850°F RESIDOOM

Hondo 850 ^°F residuum was separated into saturate, aromatic, resin, and asphaltene fractions by a modified D 2007 and asphaltene separation. Two different asphaltene precipitation solvents were used — isooctane and heptane — and differences in selected physical and chemical properties of the derived fractions were compared.

The principal difference in the use of the two solvents was weight recovery after the separation. Isooctane yielded good recovery, while heptane exhibited poor recovery. Isooctane precipitated substantially more asphaltenes, as predicted from the solubility parameters of the two solvents.

The metals concentrations in the fractions were comparable for each solvent — no metals in the saturate and aromatic fractions, approximately 300 and 1500 ppm Ni + V in the resin and asphaltene fractions respectively. The relative distribution was also similar for both solvents, with the highest percentage coming from the asphaltenes.     

VISCOSITY AND SOLUBILITY OF MIXTURES OF BITUMEN AND SOLVENT

The solubilities of three bitumen samples (Suncor, Syncrude and Lloydminster) in five solvents were examined and prediction on the various bitumen-solvent mixture viscosities were made with Cragoe equation. By calculating the Cragoe constant 'a' for each mixture and using the average value in the Cragoe equation the prediction accuracy of the equation was improved by over 60%. Bitumen-naphtha mixtures showed the best viscosity prediction characteristics.

The solubility of the asphaltenes in the bitumen was highest in toluene among the five solvents However, naphtha, showed a moderate solvating power, which negligibly varied over the range of composition studied. Therefore naphtha, a solvent derived from bitumen was recommended as the most appropriate solvent for reducing the viscosity bitumen.     

INFLUENCE OF TEMPERATURE AND SOLVENT ON THE PRECIPITATION OF ASPHALTENES

Asphaltenes has been precipitated from a Kuwait flash residue using different n-alkanes (n-C5 to n-C8) at various temperatures ranging from 4^°C to reflux temperatures of the used precipitants. Structures in the asphaltene fractions has been revealed using U.V. fluorescence spectroscopy, elemental analysis and to some extent 1H-nmr. These analysis shows that asphaltenes precipitated in the same amount but at different temperature and with different solvents have merely the same composition. For all n-alkanes the curves of precipitated amount versus temperature show maxima at about 25^°C, implying a shift in the solubility of the asphaltenes.The impact of alkane chain length on the aggregation of asphaltenes through hydrogen bonds is discussed using the alkane-alcohol system as a model. The asphaltene solubility is discussed with the help of the Scatchard-Hildebrand equation.