CN105985213A - Alkane/napthene system separation solvent screening method - Google Patents

Abstract

The invention discloses an alkane/napthene system separation solvent screening method, which belongs to the field of chemical separation. The method is characterized in that a functional group is screened to synthesize a predetermined solvent; using a real solvent for simulating a conductor-like screening model ro obtain the chemical potential of alkane and napthene in the solvent and the pure components; according to the chemical potential, an theatrical value of the infinite dilution activity coefficient of the alkane and napthene in the solvent can be obtained, and is subjected to fitting, a fitting value empirical correlation of the infinite dilution activity coefficient of alkane and napthene can be obtained; the fitting value of the infinite dilution activity coefficient of certain alkane and napthene in the solvent to be separated is obtained according to the empirical correlation, relative volatility of the alkane and napthene in the predetermined solvent can be obtained, under the condition that the relative volatility satisfies the requirement, the solubility of alkane and napthene in the predetermined solvent is calculated, if the solubility satisfies the requirement, the predetermined solvent is the separation solvent. The method has the advantages of rapidity, simpleness, accuracy and high efficiency.

Description

A kind of screening technique of alkane/cycloalkane system separation solvent

Technical field

The present invention relates to chemical separating field, particularly to the screening of a kind of alkane/cycloalkane system separation solvent Method.

Background technology

Alkane/cycloalkane system is the separation system that petrochemical industry is common.In this system, due to alkane Close with the boiling point of cycloalkane, it is easily generated nearly boiling or azeotropism, separating difficulty is high.And extracting rectifying is made For the simply efficient separating technology of one, separate solvent by adding to the top close to rectifying column, change By the relative volatility between separation component in feed liquid, the component making conventional distillation be difficult to separate (such as, is closely boiled Point system or azeotropic system) become prone to separate.So, the most generally use separation of extractive distillation technique, Under the effect suitably separating solvent, alkane/cycloalkane system is separated.From the foregoing, at alkane In the separation process of hydrocarbon/cycloalkane system, separate solvent and there is important effect, it is necessary to screening is a kind of suitable Solvent.

At present the screening criteria of the solvent used in the process of extracting rectifying is included: selectivity, dissolubility, boiling Point, density, surface tension, toxicity etc..Wherein, selectivity and the dissolubility of solvent is most important two Standard.For the selectivity of solvent, its addition referring to solvent can make the relative of component to be separated Volatility changes according to the direction of separation requirement.Solvent selectivity can relatively volatile with between component to be separated Degree represents, the selectivity of this relative volatility the highest explanation solvent is the best, is more beneficial to the separation of component to be separated. For the dissolubility of solvent, between its expectation solvent and component to be separated, there is higher mutual solubility, To prevent liquid from producing lamination in tower.But, in most cases, the solvent that selectivity is the best, Its dissolubility is the lowest, and vice versa.Therefore a kind of selectivity having had and high deliquescent solvent are provided Screening technique is particularly significant.

At present, the screening technique separating solvent used in the process of extracting rectifying substantially can be divided into following four classes:

1) character leash law: delimit to be separated according to some principle (such as molecular structure and intermolecular force) The approximate range of extractant needed for system, is typically applied to the Preliminary screening of solvent more.Follow-up also need to be by Solvent after screening is confirmed by other means further, loaded down with trivial details and inefficient.

2) activity coefficient method: by calculating each component of system to be separated activity coefficient in a solvent, and then push away Break relevant parameters such as the selectivity of each selected extraction distillation solvent, dissolubility, finally selects conjunction through contrast Suitable solvent.Owing to it needs to calculate dilution activity coefficiet or limiting dilution activity by empirical model Coefficient, needs to select specific model, reliability instability and efficiency targetedly according to different systems Relatively low.

3) computer optimization method: the solvent screening that computer technology and Chemical Engineering Thermodynamics models coupling grow up Method.It according to selective goal specify, carry out specifically chosen or design finally draw optimum solvent.Computer Optimization is broadly divided into computer aided molecular design method and computer optimization screening method two kinds, and both can tie Close and use.Wherein, computer aided molecular design method (CAMD) is selected necessarily the most in advance The molecular radical of structure, then according to certain rule is combined into molecule, and according to set solvent Molecular targets character is screened, and progressively reduces Organic substance hunting zone, eventually finds required solvent.Separately Outward, the method can also be reassembled into new solvent molecule to replace existing solvent, thus obtains maximum The economic benefit changed.But, owing to CAMD method is based on UNIFAC Group Contribution Method, and UNIFAC Group Contribution Method thinks that each group role is separate, can calculate by the character of limited functional group The character of various materials, thus can not process isomers, kindred effect and intend without experimental data The group system closed.

4) laboratory method: by measuring Vapor--Liquid Equilibrium Data or the activity coefficient of infinite dilute solution, calculate phase To volatility, thus the method that solvent is screened.Mainly use flat owing to measuring gas-liquid phase equilibrium data Weighing apparatus still method, for different separation systems, need to change different equilibrium stills, and time-consuming length and workload are big.

Inventor finds that prior art at least exists techniques below problem:

The screening technique separating solvent during the extracting rectifying that prior art provides all has certain limitation Property, it is impossible to filter out desired separation solvent quickly, simply, accurately and efficiently.

Summary of the invention

Embodiment of the present invention technical problem to be solved is, it is provided that a kind of quickly, simple, accurately and The screening technique of efficient alkane/cycloalkane system separation solvent.Concrete technical scheme is as follows:

Embodiments provide the screening technique of a kind of alkane/cycloalkane system separation solvent, including:

Step a, from the synthesis group of solvent molecule, screen backbone radical and functional group, and utilize described bone Frame group and described functional group synthesis predetermined solvent；

Step b, utilize true solvent quasi-conductor screening model, calculate respectively at least 3 kinds of alkane chemical potential, Chemical potential in described predetermined solvent of the chemical potential of at least 3 kinds of cycloalkane, described at least 3 kinds of alkane, with And the chemical potential that described at least 3 kinds of cycloalkane are in described predetermined solvent, then according to infinite dilution activity system Number computing formula, obtain described at least 3 kinds of alkane dilution activity coefficiet reason in described predetermined solvent Opinion value and described at least 3 kinds of cycloalkane dilution activity coefficiet theoretical value in described predetermined solvent；

Step c, by described at least 3 kinds of alkane dilution activity coefficiet theoretical value in described predetermined solvent It is fitted with described at least 3 kinds of alkane dilution activity coefficiet literature value in described predetermined solvent, Obtain the Empirical Equation of alkane dilution activity coefficiet match value in described predetermined solvent；

Correspondingly, by described at least 3 kinds of cycloalkane in described predetermined solvent dilution activity coefficiet reason Opinion value and described at least 3 kinds of cycloalkane dilution activity coefficiet literature value in described predetermined solvent are carried out Matching, obtains the Empirical Equation of cycloalkane dilution activity coefficiet match value in described predetermined solvent；

Step d, from alkane/cycloalkane system, determine that alkane to be separated and cycloalkane are respectively as the first alkane Hydrocarbon and the first cycloalkane, obtain respectively described first alkane and the chemical potential of described first cycloalkane and they Chemical potential in described predetermined solvent, and then obtain described first alkane respectively and described first cycloalkane exists Dilution activity coefficiet theoretical value in described predetermined solvent, then utilizes described alkane described predetermined molten The Empirical Equation of the dilution activity coefficiet match value in agent and described cycloalkane are in described predetermined solvent In the Empirical Equation of dilution activity coefficiet match value, respectively obtain described first alkane and described One cycloalkane dilution activity coefficiet match value in described predetermined solvent；

Step e, the infinite dilution in described predetermined solvent according to described first alkane and described first cycloalkane Activity coefficient match value, utilizes relative volatility computing formula, obtains described first alkane and described first ring Alkane relative volatility in described predetermined solvent；

Step f, when described first alkane and described first cycloalkane the relative volatility in described predetermined solvent During more than or equal to 1.2, carry out step g；

When described first alkane and described first cycloalkane, the relative volatility in described predetermined solvent is less than 1.2 Time, re-start step a to step e, until described first alkane and described first cycloalkane are described predetermined Relative volatility in solvent is more than or equal to 1.2；

Described step g includes: according to described first alkane and the chemical potential of described first cycloalkane and they Chemical potential in described predetermined solvent, utilizes Calculation of Solubility formula, respectively obtain described first alkane and Described first cycloalkane dissolubility in described predetermined solvent, when described first alkane and described first cycloalkanes When hydrocarbon dissolubility in described predetermined solvent is all higher than equal to 0.3g/g solvent, determine that described predetermined solvent is Separate described first alkane and the solvent of described first cycloalkane.

Specifically, in described step a, the synthesis group of described solvent molecule is by backbone radical and functional group Composition；

Described backbone radical includes: CH₃、CH₂、CH、C、Cy-CH₂、Cy-CH、Cy-C、ACH、 AC、ACCH3、ACCH₂Or ACCH, wherein, Cy is cycloalkyl group, and A is phenyl；

Described functional group includes: OH, CH₃CO、CH₂CO、CH₃COO、CH₂COO、HCOO、 CH-O、CH₂NH₂、CHNH₂、CHNH₂、CN、CNH₂、CH₃NH、CH₂NH、CHNH、 CH₃N、CH₂N、CH₂CN、COOH、CH₂NO₂、CH₂SH、HCON(CH₂)₂、CON(CH₃)₂、 CON(CH₂)₂、CON(CH₂)CH、CONHCH₃、Cy-CH₂OCH₂、Cy-CONCH₃、 Cy-CONCH₂、Cy-CONCH、Cy-CONC、ACOH、ACNH₂, ACH-N=ACH, AC-N=ACH or AC-N=AC, wherein, Cy is cycloalkyl group, and A is phenyl.

Specifically, in described predetermined solvent, the number of described functional group is 1 or 2.

Specifically, in described step b, described dilution activity coefficiet computing formula is:

$\ln {\mathrm{\γ}}_i=({\mathrm{\μ}}_i^{\left(S\right)}-{\mathrm{\μ}}_i^{\left(P\right)})/\mathrm{RT}$

Wherein, γ_iFor component i dilution activity coefficiet theoretical value in a solvent,For component i molten Chemical potential in agent,For the chemical potential of component i, R is gas constant: 8.314J/mol K, T are temperature Degree, unit is K.

Specifically, in described step c, using described dilution activity coefficiet theoretical value as abscissa, will Described dilution activity coefficiet literature value, as abscissa, carries out described matching by method of least square, Empirical Equation to described dilution activity coefficiet match value；

The Empirical Equation of described dilution activity coefficiet match value is:

$\ln {\mathrm{\γ}}_{\mathrm{correlated}}^{\∞}=a+b\·\ln {\mathrm{\γ}}_i^{\∞}+c\·{\left(\ln {\mathrm{\γ}}_i^{\∞}\right)}^2+d\·{\left(\ln {\mathrm{\γ}}_i^{\∞}\right)}^3+e\·{\left(\ln {\mathrm{\γ}}_i^{\∞}\right)}^4$

Wherein, a, b, c, d, e are the constant determined by described matching,For component i in a solvent Dilution activity coefficiet theoretical value,For the dilution activity coefficiet matching in a solvent of component i Value.

Specifically, in described step e, described relative volatility computing formula is:

${\mathrm{\α}}_{\mathrm{ij}}=\frac{{\mathrm{\γ}}_{i-\mathrm{correlated}}^{\∞}{P}_i^S}{{\mathrm{\γ}}_{j-\mathrm{correlated}}^{\∞}{P}_j^S}$

Wherein, α_ijFor component i and component j relative volatility in a solvent,For component i molten Dilution activity coefficiet match value in agent,For the saturated vapour pressure of component i,For component j Dilution activity coefficiet match value in a solvent,Saturated vapour pressure for component j.

Specifically, described Calculation of Solubility formula is:

${\log }_{10}\left(x_i\right)={\log }_{10}\left[\exp (({\mathrm{\μ}}_i^{\left(P\right)}-{\mathrm{\μ}}_i^{\left(S\right)}-\mathrm{\Δ}{G}_{i,\mathrm{fusion}})/\mathrm{RT})\right]$

Wherein, x_iFor component i dissolubility in a solvent,For the chemical potential of component i,For component i Chemical potential in a solvent, Δ G_i,fusionFor the melted free energy of component i, being 0 during liquid phase, R is gas constant: 8.314J/mol K, T are temperature, and unit is K.

The technical scheme that the embodiment of the present invention provides has the benefit that

The screening technique of alkane/cycloalkane system separation solvent that the embodiment of the present invention provides, by using skeleton Group and functional group synthesis predetermined solvent.Then true solvent quasi-conductor screening model is utilized to calculate alkane/ring At least 3 kinds of alkane of alkane system and the chemical potential of at least 3 kinds of cycloalkane, and they are in predetermined solvent Chemical potential, thus obtain above-mentioned at least 3 kinds of alkane and at least 3 according to dilution activity coefficiet computing formula Plant cycloalkane infinite dilution coefficient theoretical value in predetermined solvent, then recycle the most above-mentioned at least 3 Kind of alkane and at least 3 kinds of cycloalkane infinite dilution coefficient literature value in predetermined solvent is fitted, and distinguishes Obtain alkane and the Empirical Equation of cycloalkane dilution activity coefficiet match value in predetermined solvent.From Alkane/cycloalkane system is determined the specific a kind of alkane and a kind of cycloalkane needing to separate, respectively as First alkane and the first cycloalkane, obtain the first alkane and the first cycloalkane above-mentioned predetermined according to said method Dilution activity coefficiet theoretical value in solvent, and pre-at this according to obtained alkane and cycloalkane respectively Determine the Empirical Equation of dilution activity coefficiet match value in solvent, obtain the first alkane and the first cycloalkanes Hydrocarbon match value in this predetermined solvent, and then obtain this first alkane and the first cycloalkane in this predetermined solvent In relative volatility.On the premise of guaranteeing that this relative volatility meets requirement, calculate the first alkane respectively With first cycloalkane dissolubility in this predetermined solvent, when the dissolubility obtained also meet require time, Determine that this predetermined solvent can be as the separation of extractive distillation solvent of the first alkane and the first cycloalkane.

From the foregoing, the method that the embodiment of the present invention provides, first aspect, functional group tentatively ensure that Synthesized predetermined solvent has desired polarity, it is to avoid the blindness of solvent primary dcreening operation and one-sidedness, thus carries High solvent screening efficiency.Second aspect, the true solvent quasi-conductor screening model used can calculate all of Organic solvent and isomers thereof.Even if lacking related component, it is possible to obtain group by quantum chemistry calculation The information divided, is calculated by this model the most again.Therefore, compared to Group Contribution Method such as UNIFAC, The applicable dicyandiamide solution of present invention institute is the most extensive.The third aspect, obtained alkane and cycloalkane are in advance Determine the Empirical Equation of the dilution activity coefficiet match value in solvent can be applicable to most alkane and Cycloalkane, it is possible to easily obtain the dilutest in this predetermined solvent of different alkane and different rings alkane Release activity coefficient match value.And, by utilizing dilution activity coefficiet literature value to be fitted, this nothing The reliability of limit dilution activity coefficient match value is with to utilize the obtained data of test method basically identical.So keep away Exempt from loaded down with trivial details each different alkane and cycloalkane are tested, reduce time and the expense of solvent screening With, quickly, simpler and further increase the screening efficiency of solvent.Fourth aspect, the present invention is by molten The dissolubility of agent and the standard selectively as solvent screening, improve the accuracy of solvent screening.And, In order to avoid unnecessary operation, on the premise of the selectivity of solvent meets requirement, just carry out Solvent Solubility Judge process, be more conducive to improve solvent screening efficiency.

Accompanying drawing explanation

For the technical scheme being illustrated more clearly that in the embodiment of the present invention, institute in embodiment being described below The accompanying drawing used is needed to be briefly described, it should be apparent that, the accompanying drawing in describing below is only the present invention Some embodiments, for those of ordinary skill in the art, on the premise of not paying creative work, Other accompanying drawing can also be obtained according to these accompanying drawings.

Fig. 1-1 is the dilution activity coefficiet matched curve in acetonitrile of the alkane of the embodiment of the present invention 1 offer Figure；

Fig. 1-2 is that the dilution activity coefficiet matching in acetonitrile of the cycloalkane of the embodiment of the present invention 1 offer is bent Line chart；

Fig. 2 is alkane and the cycloalkane nothing in DMF of the embodiment of the present invention 2 offer Limit dilution activity coefficient matched curve figure；

Fig. 3 is the alkane that provides of the embodiment of the present invention 3 and the dilutest in N-Methyl pyrrolidone of cycloalkane Release activity coefficient matched curve figure；

Fig. 4 is the alkane that provides of the embodiment of the present invention 4 and cycloalkane infinite dilution activity system in ethylene glycol Number matched curve figure；

Fig. 5 is alkane and the cycloalkane infinite dilution activity in diethylene glycol of the embodiment of the present invention 5 offer Coefficient Fitting curve chart.

Detailed description of the invention

For making technical scheme and advantage clearer, below in conjunction with accompanying drawing to embodiment party of the present invention Formula is described in further detail.

Unless otherwise defined, all technical terms used by the embodiment of the present invention are respectively provided with and people in the art The identical implication that member is generally understood that.Before embodiment of the present invention is described further in detail, right Understand that some terms of the embodiment of the present invention provide definition.

1), in the embodiment of the present invention, described " alkane " refers to alkane.

2), in the embodiment of the present invention, described " chemical potential of alkane ", " chemical potential of cycloalkane " refer to respectively It is chemical potential and the chemical potential of cycloalkane pure component of alkane pure component.

3) in the embodiment of the present invention, described " alkane infinite dilution activity system in (described) predetermined solvent The Empirical Equation of number match value " refer to class alkane dilution activity coefficiet in predetermined solvent The Empirical Equation of match value, it is the dilutest in predetermined solvent that it is applicable to calculate various different alkane Release activity coefficient match value.Similarly, described " cycloalkane infinite dilution in (described) predetermined solvent The Empirical Equation of activity coefficient match value " there is similar implication.

4) " dilution activity coefficiet literature value " described in the embodiment of the present invention refers to according to existing skill Some different specific alkane recognized by this area or ring disclosed in the document of art offer or other information channels Alkane dilution activity coefficiet empirical value in described predetermined solvent, those skilled in the art are by looking into Read related art can be readily available.

5) " the first alkane " described in the embodiment of the present invention refers to belong to a kind of optional of paraffinic Alkane, it does not have specific implication, and it can be or may not be the embodiment of the present invention and calculate chemistry Any one in " alkane at least 3 " applied during gesture.Similarly, " the first cycloalkane " There is similar implication.

Embodiments provide the screening technique of a kind of alkane/cycloalkane system separation solvent, including following Step:

Step 101, from the synthesis group of solvent molecule, screen backbone radical and functional group, and utilize described Backbone radical and described functional group synthesis predetermined solvent.

The embodiment of the present invention carries out primary dcreening operation by step 101 to solvent, and first-selection selects the function base of solvent molecule By functional group, group, primarily determines that synthesized solvent has desired energy and changes alkane to be separated and ring The polarity of the Interaction Force of alkane, it is to avoid the blindness of solvent primary dcreening operation and one-sidedness, thus improve solvent Screening efficiency.

Specifically, the synthesis group of the solvent molecule described in the embodiment of the present invention is by backbone radical and function base Group's composition, wherein, backbone radical includes: CH₃、CH₂、CH、C、Cy-CH₂、Cy-CH、Cy-C、 ACH、AC、ACCH3、ACCH₂Or ACCH, wherein, Cy is cycloalkyl group, and A is phenyl；Merit Can include by group: OH, CH₃CO、CH₂CO、CH₃COO、CH₂COO、HCOO、CH-O、CH₂NH₂、 CHNH₂、CHNH₂、CN、CNH₂、CH₃NH、CH₂NH、CHNH、CH₃N、CH₂N、CH₂CN、 COOH、CH₂NO₂、CH₂SH、HCON(CH₂)₂、CON(CH₃)₂、CON(CH₂)₂、CON(CH₂)CH、 CONHCH₃、Cy-CH₂OCH₂、Cy-CONCH₃、Cy-CONCH₂、Cy-CONCH、Cy-CONC、 ACOH、ACNH₂, ACH-N=ACH, AC-N=ACH or AC-N=AC, wherein, Cy is cycloalkanes Alkyl, A is phenyl.

It is combined by the backbone radical that Preliminary screening is good and functional group, predetermined solvent can be synthesized. It will be appreciated by persons skilled in the art that, in synthesized solvent, the number of functional group is generally 1 Or 2.

Step 102, utilize true solvent quasi-conductor screening model, calculate respectively at least 3 kinds of alkane chemical potential, Chemical potential in predetermined solvent of the chemical potential of at least 3 kinds of cycloalkane, these at least 3 kinds of alkane and this extremely Few 3 kinds of cycloalkane chemical potential in predetermined solvent, then according to dilution activity coefficiet computing formula, Obtain these at least 3 kinds of alkane dilution activity coefficiet theoretical value in predetermined solvent and at least 3 kinds of rings Alkane dilution activity coefficiet theoretical value in predetermined solvent.

" true solvent quasi-conductor screening model " described in the embodiment of the present invention that is COSMO-RS, refer to Be the common thermodynamical model in this area, it can be " true solvent quasi-conductor screening model (COSMO-RS) " described in (Mu Tiancheng, chemical progress, the 10th phase of volume 20).For example, It can be the COSMOtherm software of COSMOlogic GmbH&Co.KG company exploitation, this area Simulation that technical staff can carry out Related Mathematical Models easily with it and calculating.

It is understood that utilize true solvent quasi-conductor screening model to calculate alkane or cycloalkane pure component Chemical potential and their chemical potentials in certain solvent be state of the art.Those skilled in the art By inputting alkane pure component and/or the molecular formula of this solvent in true solvent quasi-conductor screening model, It is readily available above-mentioned each chemical potential.

In order to realize follow-up fit procedure, from alkane/cycloalkane system, choose at least 3 kinds respectively (such as 3-10 kind etc.) alkane and at least 3 kinds of cycloalkane carries out the calculating of chemical potential.Wherein it is preferred to, selected Alkane and such class alkane and the cycloalkane of cycloalkane, they infinite dilution activity in this predetermined solvent Coefficient literature value is known to those skilled in the art.

Wherein, dilution activity coefficiet computing formula is:

$\ln {\mathrm{\γ}}_i=({\mathrm{\μ}}_i^{\left(S\right)}-{\mathrm{\μ}}_i^{\left(P\right)})/\mathrm{RT}$

Wherein, γ_iFor component i dilution activity coefficiet theoretical value in a solvent,For component i molten Chemical potential in agent,For the chemical potential of component i, R is gas constant: 8.314J/ (mol K), and T is Temperature (K).It will be appreciated by persons skilled in the art that described in the embodiment of the present invention in computing formula Temperature T refers to the temperature of system.In this dilution activity coefficiet computing formula, component i can be managed Solve as to refer to above-mentioned at least 3 kind alkane or at least 3 kinds of cycloalkane.

The true solvent quasi-conductor screening model used due to the embodiment of the present invention can calculate all of organic molten Agent and isomers thereof.Even if lacking related component, it is possible to obtained the letter of component by quantum chemistry calculation Breath, is calculated by this model the most again.Therefore, compared to the Group Contribution Method such as UNIFAC, the present invention The applicable dicyandiamide solution of institute is the most extensive.

Step 103, the infinite dilution in predetermined solvent of these at least 3 kinds of alkane of obtaining in step 102 is lived Degree coefficient theoretical value and these at least 3 kinds of alkane dilution activity coefficiet literature value in predetermined solvent are carried out Matching, obtains the Empirical Equation of alkane dilution activity coefficiet match value in predetermined solvent；

Correspondingly, by least 3 kinds of cycloalkane dilution activity coefficiet theoretical value in described predetermined solvent At least 3 kinds of cycloalkane dilution activity coefficiet literature value in predetermined solvent is fitted, and obtains ring The Empirical Equation of alkane dilution activity coefficiet match value in predetermined solvent.

In order to improve the accuracy of required dilution activity coefficiet, step 103 is lived by utilizing infinite dilution Dilution activity coefficiet theoretical value obtained in degree coefficient literature value and step 102 is fitted obtaining nothing Limit dilution activity coefficient match value.The reliability of this dilution activity coefficiet match value with utilize test method Obtained data are basically identical, it is to avoid loaded down with trivial details process of the test, reduce time and the expense of solvent screening, More quick, simple and further increase the screening efficiency of solvent.

Specifically, will unlimited in predetermined solvent of at least 3 kinds of alkane (or, at least 3 kinds of cycloalkane) Dilution activity coefficient theoretical value as abscissa, accordingly, by these at least 3 kinds of alkane (or, at least 3 Kind of cycloalkane) dilution activity coefficiet literature value in predetermined solvent as abscissa, pass through Matlab Programming, utilizes method of least square to carry out above-mentioned fit procedure, obtains the nothing of alkane (or, cycloalkane) The Empirical Equation of limit dilution activity coefficient match value.

The Empirical Equation of this dilution activity coefficiet match value is:

$\ln {\mathrm{\γ}}_{\mathrm{correlated}}^{\∞}=a+b\·\ln {\mathrm{\γ}}_i^{\∞}+c\·{\left(\ln {\mathrm{\γ}}_i^{\∞}\right)}^2+d\·{\left(\ln {\mathrm{\γ}}_i^{\∞}\right)}^3+e\·{\left(\ln {\mathrm{\γ}}_i^{\∞}\right)}^4$

Wherein, a, b, c, d, e are the constant determined by described matching,For component i in a solvent Dilution activity coefficiet theoretical value,For the dilution activity coefficiet matching in a solvent of component i Value.In the Empirical Equation of this dilution activity coefficiet match value, component i can be understood as referring to appoint A kind of alkane of meaning or any one cycloalkane.

For example, it is also possible to map in Origin software, and utilize the fitting of a polynomial merit in this software Above-mentioned a, b, c, d, e parameter can be obtained, i.e. obtain the Empirical Equation of dilution activity coefficiet match value.

Alkane obtained by above-mentioned and the warp of cycloalkane dilution activity coefficiet match value in predetermined solvent Test correlation and can be applicable to most alkane and cycloalkane, it is possible to easily obtain any one not The dilution activity coefficiet match value in this predetermined solvent with alkane and different rings alkane.And, pass through Dilution activity coefficiet literature value is utilized to be fitted, the reliability of this dilution activity coefficiet match value The obtained data of test method are basically identical with utilizing.So avoid loaded down with trivial details to each different alkane and Cycloalkane is tested, and reduces time and the expense of solvent screening, more quickly, simply and further carries The high screening efficiency of solvent.

Visible, for the computing formula of the above-mentioned dilution activity coefficiet match value of specific solvent, that is alkane Matching is only needed once on the Empirical Equation of hydrocarbon or cycloalkane system dilution activity coefficiet in a solvent, Just can be used for calculating the dilutest in this solvent of corresponding alkane or the homologue of cycloalkane or isomers Release the match value of activity coefficient, fill up the blank of experimental data, substantial amounts of time and expense can also be saved equally With, have great importance for improving solvent screening efficiency.

Step 104, from alkane/cycloalkane system, determine that alkane to be separated and cycloalkane are respectively as first Alkane and the first cycloalkane, obtain the first alkane and the chemical potential of the first cycloalkane respectively and they be predetermined Chemical potential in solvent, and then obtain the dilutest in predetermined solvent of the first alkane and the first cycloalkane respectively Release activity coefficient theoretical value, then utilize alkane dilution activity coefficiet match value in predetermined solvent The empirical correlation of Empirical Equation and the cycloalkane dilution activity coefficiet match value in predetermined solvent Formula, respectively obtains the first alkane and the first cycloalkane dilution activity coefficiet match value in predetermined solvent.

In step 104, by determining that alkane to be separated and cycloalkane are made respectively from alkane/cycloalkane system Be the first alkane and the first cycloalkane, obtain the chemical potential of the first alkane, the chemical potential of the first cycloalkane, First alkane chemical potential in predetermined solvent and first cycloalkane chemical potential in predetermined solvent.So Rear above-mentioned dilution activity coefficiet computing formula is utilized to be calculated first alkane nothing in predetermined solvent Limit dilution activity coefficient theoretical value and first cycloalkane dilution activity coefficiet in predetermined solvent are theoretical Value.Then the Empirical Equation of alkane dilution activity coefficiet match value in predetermined solvent it is utilized respectively And the Empirical Equation of the dilution activity coefficiet match value that cycloalkane is in predetermined solvent, accordingly To first alkane dilution activity coefficiet match value in predetermined solvent and the first cycloalkane in predetermined solvent In dilution activity coefficiet match value.

It is, of course, also possible to repeatedly determine from alkane/cycloalkane system to be separated be different from the first alkane and/or The alkane of the first cycloalkane and cycloalkane are as alkane to be separated and cycloalkane.And carry out the following behaviour being similar to Make.

Step 105, intend according to dilution activity coefficiet in predetermined solvent of the first alkane and the first cycloalkane Conjunction value, utilizes relative volatility computing formula, obtains the first alkane and the first cycloalkane in predetermined solvent Relative volatility.

Specifically, this relative volatility computing formula is:

${\mathrm{\α}}_{\mathrm{ij}}=\frac{{\mathrm{\γ}}_{i-\mathrm{correlated}}^{\∞}{P}_i^S}{{\mathrm{\γ}}_{j-\mathrm{correlated}}^{\∞}{P}_j^S}$

Wherein, α_ijFor component i and component j relative volatility in a solvent,For component i molten Dilution activity coefficiet match value in agent,For the saturated vapour pressure of component i,For component j Dilution activity coefficiet match value in a solvent,Saturated vapour pressure for component j.Wherein, these public affairs In formula, component i and component j can be understood as referring respectively to the first alkane and the first cycloalkane.Component i and group The saturated vapor pressure dividing j is definite value, can obtain by consulting chemical industry handbook.

Proceeding step 106 after having carried out step 105, in the embodiment of the present invention, step 106 includes appointing Meaning selects the step 1061 carried out and a step 1062.

Step 1061 is: when the first alkane and the first cycloalkane, the relative volatility in predetermined solvent is more than In 1.2 time, carry out step 107: according to the first alkane and the chemical potential of the first cycloalkane and they are predetermined Chemical potential in solvent, utilizes Calculation of Solubility formula, respectively obtains the first alkane and the first cycloalkane in advance Determining the dissolubility in solvent, when the first alkane and the first cycloalkane, the dissolubility in predetermined solvent is all higher than In 0.3g/g solvent, during preferably greater than or equal to 0.5g/g solvent, determine predetermined solvent be separate the first alkane and The solvent of the first cycloalkane.

It is understood that the first alkane and the chemical potential of the first cycloalkane and they are in predetermined solvent Chemical potential refers to the chemical potential of the first alkane, the chemical potential of the first cycloalkane, the first alkane in predetermined solvent In chemical potential, first cycloalkane chemical potential in predetermined solvent.Similarly, they are also by utilizing True solvent quasi-conductor screening model obtains.

Specifically, Calculation of Solubility formula is:

${\log }_{10}\left(x_i\right)={\log }_{10}\left[\exp (({\mathrm{\μ}}_i^{\left(P\right)}-{\mathrm{\μ}}_i^{\left(S\right)}-\mathrm{\Δ}{G}_{i,\mathrm{fusion}})/\mathrm{RT})\right]$

Wherein, x_iFor component i dissolubility in a solvent,For the chemical potential of component i,For component i Chemical potential in a solvent, Δ G_i,fusionFor the melted free energy of component i, being 0 during liquid phase, R is gas constant: 8.314J/mol K, T are temperature, and unit is K.

Step 1062: the relative volatility in predetermined solvent is less than 1.2 when the first alkane and the first cycloalkane Time, re-start step 101 to step 105, until the first alkane and the first cycloalkane are the most predetermined molten Relative volatility in agent is more than or equal to 1.2.

Visible, first the dissolubility of solvent is judged by the embodiment of the present invention by step 106, when first When alkane and first cycloalkane relative volatility in predetermined solvent are more than or equal to 1.2, step can be represented The selectivity of predetermined solvent synthesized in 101 meets requirement.On this basis, can down carry out this to make a reservation for The judgement of Solvent Solubility.When the first alkane and the first cycloalkane, the relative volatility in predetermined solvent is less than During equal to 1.2, can represent that the selectivity of predetermined solvent synthesized in step 101 is unsatisfactory for requirement, Re-start step 101 to step 105, until the first alkane and the first cycloalkane are in the most predetermined solvent Relative volatility more than or equal to 1.2.Since Ru Ci, it is to avoid useless operating process, not only simplify behaviour Make process, and improve the efficiency of solvent screening.

And by ensureing that predetermined solvent has excellent selectivity and dissolubility in step 107, molten by solvent Xie Du and the standard selectively as solvent screening, the character of the solvent investigated is the most accurate, improves molten The accuracy of agent screening.

Method described in the embodiment of the present invention is applicable to separate the alkane/cycloalkane body with 4-12 carbon atom System, preferable separate have 5-9 carbon atom alkane/cycloalkane system.For example, this alkane is permissible For butane, 2-methybutane, pentane, 2,2-dimethylbutane, 2, the alkane such as 3-dimethylbutane, hexane Hydrocarbon.This cycloalkane can be Pentamethylene., hexamethylene, methyl cyclopentane, hexahydrotoluene, ethyl cyclohexane, The cycloalkane such as butyl cyclohexane.

Hereinafter will be further described through the present invention by specific embodiment.

The unreceipted condition person of operating process in specific examples below, all according to normal condition or manufacturer The condition of suggestion is carried out.Raw materials used unreceipted production firm and specification person be can by city available from Conventional products.

Embodiment 1

The present embodiment screens backbone radical CH from the synthesis group of solvent molecule₃With functional group CN, and profit Predetermined solvent has been synthesized: acetonitrile (CH with this backbone radical and functional group₃And whether investigated acetonitrile CN), Can be as the separation solvent of alkane/cycloalkane system.Step is as follows:

Utilize true solvent quasi-conductor screening model, calculate the chemical potential of multiple alkane, multiple cycloalkanes respectively The chemical potential of hydrocarbon and their chemical potentials in acetonitrile, then calculate public affairs according to dilution activity coefficiet Formula, obtains this multiple alkane and the multiple cycloalkane dilution activity coefficiet theoretical value in acetonitrile.Should Multiple alkane dilution activity coefficiet theoretical value in acetonitrile is as abscissa, accordingly, by this this many Kind of alkane dilution activity coefficiet literature value in acetonitrile as abscissa, carried out by origin software on The fit procedure stated, obtains the Empirical Equation of the dilution activity coefficiet match value of alkane.Alkane is in second Dilution activity coefficiet theoretical value in nitrile and the matched curve of literature value are as Figure 1-1.Similarly, Matched curve such as Fig. 1-2 institute to cycloalkane dilution activity coefficiet theoretical value in acetonitrile and literature value Show.

Wherein, under conditions of 25 DEG C, above-mentioned various alkane and cycloalkane dilution activity coefficiet in acetonitrile Relative deviation before and after matching is as shown in table 1:

Alkane and the cycloalkane ln γ in acetonitrile during 1 25 DEG C of table^∞Fitness bias

As shown in Table 1, above-mentioned various alkane and the cycloalkane average phase of dilution activity coefficiet in acetonitrile Deviation 22.78% become after matching 0.97% before matching, illustrates that this Empirical Equation can be quick To the dilution activity coefficiet being closer to experiment value, thus the screening for solvent provides safeguard.

Determine from alkane/cycloalkane system alkane to be separated and cycloalkane be respectively 2,2-dimethylbutane and Pentamethylene., obtains 2,2-dimethylbutane and the chemical potential of Pentamethylene. and their chemistry in acetonitrile respectively Gesture, and then obtain 2 respectively, 2-dimethylbutane and the Pentamethylene. dilution activity coefficiet in acetonitrile is theoretical Value, then utilizes Empirical Equation and the cycloalkanes of alkane dilution activity coefficiet match value in acetonitrile The Empirical Equation of hydrocarbon dilution activity coefficiet match value in acetonitrile, respectively obtains 2,2-dimethylbutane Being respectively 16.11 and 25.57 with Pentamethylene. dilution activity coefficiet match value in acetonitrile, both is saturated Vapour pressure is respectively 42.33 and 42.74kPa, thus obtains calculation and obtain 2, and 2-dimethylbutane and Pentamethylene. are at acetonitrile In relative volatility be 1.60, its selectivity meets requirement.Then Pentamethylene. and 2,2-dimethyl it are calculated Butane dissolubility in acetonitrile is respectively 0.064g/g solvent and 0.042g/g solvent.Consider relatively volatile Degree and dissolubility, acetonitrile is to Pentamethylene. and 2, and the solubility property of 2-dimethylbutane is poor, holds when extracting rectifying Biphase operation easily occurs, is not therefore preferably solvent.

Embodiment 2

The operating procedure of the present embodiment is same as in Example 1, and difference is that the functional group chosen in district is CON(CH₃)₂, the solvent molecule of synthesis is DMF (DMF).

Utilize the alkane obtained by the method that the embodiment of the present invention provides and cycloalkane at N, N-dimethyl formyl The dilution activity coefficiet theoretical value of amine and the matched curve of literature value are as shown in Figure 2.Wherein, 25 DEG C Under the conditions of, relative deviation before and after dilution activity coefficiet matching is such as in DMF for various alkane and cycloalkane Shown in table 2:

Alkane and the cycloalkane ln γ in DMF during 2 25 DEG C of table^∞Fitness bias

As can be seen from Table 2 the dilution activity coefficiet after over-fitting and literature value closer to.Utilize The calculated Pentamethylene. of method that the embodiment of the present invention provides and unlimited in DMF of 2,2-dimethylbutane Dilution activity coefficient is respectively 8.46 and 15.38, and both saturated vapour pressures are respectively 42.33 and 42.74kPa, Thus being calculated relative volatility is 1.84.

Calculate Pentamethylene. and 2,2-dimethylbutane dissolubility in DMF be respectively 0.439g/g solvent and 0.416g/g solvent.Considering relative volatility and dissolubility, DMF is to Pentamethylene. and 2,2-dimethyl butyrate The solubility property of alkane is preferable, also has higher relative volatility, can reach 1.84, therefore, and can be as preferably Solvent.

Embodiment 3

The operating procedure of the present embodiment is same as in Example 1, and difference is that the functional group chosen is CON(CH₂)₂, the solvent molecule of synthesis is N-Methyl pyrrolidone (NMP), each alkane and cycloalkane In the literature value of dilution activity coefficiet of N-Methyl pyrrolidone and theoretical value as it is shown on figure 3, matching obtains Empirical Equation to dilution activity coefficiet match value.Before and after matching, dilution activity coefficiet is relative Deviation is shown in Table 3.

Alkane and the cycloalkane ln γ in NMP during 3 25 DEG C of table^∞Fitness bias

As shown in Table 3, the dilution activity coefficiet after over-fitting and literature value closer to.Utilize this The calculated Pentamethylene. of method that inventive embodiments provides and the dilutest in NMP of 2,2-dimethylbutane Releasing activity coefficient and be respectively 7.69 and 12.73, both saturated vapour pressures are respectively 42.33 and 42.74kPa, Thus being calculated relative volatility is 1.67.

Calculate Pentamethylene. and 2,2-dimethylbutane dissolubility in NMP be respectively 0.649g/g solvent and 0.629g/g solvent.Considering relative volatility and dissolubility, NMP is to Pentamethylene. and 2,2-dimethyl butyrate The solubility property of alkane is preferable, and relative volatility can also reach 1.67, the most also can be as preferred solvent.

Embodiment 4

The operating procedure of the present embodiment is same as in Example 1, and difference is that the functional group chosen is OH, closes The solvent molecule become is ethylene glycol, each alkane and the cycloalkane dilution activity coefficiet in ethylene glycol As shown in Figure 4, matching obtains the Empirical Equation of dilution activity coefficiet match value for literature value and theoretical value. Before and after matching, the relative deviation of dilution activity coefficiet is shown in Table 4.

Alkane and the cycloalkane ln γ in ethylene glycol during 4 25 DEG C of table^∞Fitness bias

As shown in Table 4, the dilution activity coefficiet after over-fitting and literature value closer to.Utilize this The calculated Pentamethylene. of method that inventive embodiments provides and the dilutest in NMP of 2,2-dimethylbutane Releasing activity coefficient and be respectively 106.47 and 383.88, both saturated vapour pressures are respectively 42.33 and 42.74kPa, Thus being calculated relative volatility is 3.61.

Calculate Pentamethylene. and 2,2-dimethylbutane dissolubility in NMP be respectively 0.047g/g solvent and 0.031g/g solvent.Considering relative volatility and dissolubility, ethylene glycol is to Pentamethylene. and 2,2-dimethyl butyrate The solubility property of alkane is poor, biphase operation easily occurs when extracting rectifying, is not therefore preferably solvent.

Embodiment 5

The operating procedure of the present embodiment is same as in Example 1, and difference is that the functional group chosen is OH, closes The solvent molecule become is diethylene glycol, each alkane and the cycloalkane infinite dilution activity system in diethylene glycol Number literature value and theoretical value as it is shown in figure 5, matching obtain dilution activity coefficiet match value through customs examination Connection formula.Before and after matching, the relative deviation of dilution activity coefficiet is shown in Table 5.

Alkane and the cycloalkane ln γ in diethylene glycol during 5 25 DEG C of table^∞Fitness bias

As shown in Table 5, the dilution activity coefficiet after over-fitting and literature value closer to.Utilize this The calculated Pentamethylene. of method that inventive embodiments provides and the dilutest in NMP of 2,2-dimethylbutane Releasing activity coefficient and be respectively 35.78 and 78.40, both saturated vapour pressures are respectively 42.33 and 42.74kPa, Thus being calculated relative volatility is 2.21.

Calculate Pentamethylene. and 2,2-dimethylbutane dissolubility in NMP be respectively 0.092g/g solvent and 0.071g/g solvent.Considering relative volatility and dissolubility, ethylene glycol is to Pentamethylene. and 2,2-dimethyl butyrate The solubility property of alkane is poor, biphase operation easily occurs when extracting rectifying, is not therefore preferably solvent.

The foregoing is only presently preferred embodiments of the present invention, not in order to limit the scope of the invention, all Within the spirit and principles in the present invention, any modification, equivalent substitution and improvement etc. made, all should comprise Within protection scope of the present invention.

Claims (7)

1. a screening technique for alkane/cycloalkane system separation solvent, including:

Step a, from the synthesis group of solvent molecule, screen backbone radical and functional group, and utilize described bone Frame group and described functional group synthesis predetermined solvent；

Step b, utilize true solvent quasi-conductor screening model, calculate respectively at least 3 kinds of alkane chemical potential, Chemical potential in described predetermined solvent of the chemical potential of at least 3 kinds of cycloalkane, described at least 3 kinds of alkane, with And the chemical potential that described at least 3 kinds of cycloalkane are in described predetermined solvent, then according to infinite dilution activity system Number computing formula, obtain described at least 3 kinds of alkane dilution activity coefficiet reason in described predetermined solvent Opinion value and described at least 3 kinds of cycloalkane dilution activity coefficiet theoretical value in described predetermined solvent；

Step c, by described at least 3 kinds of alkane dilution activity coefficiet theoretical value in described predetermined solvent It is fitted with described at least 3 kinds of alkane dilution activity coefficiet literature value in described predetermined solvent, Obtain the Empirical Equation of alkane dilution activity coefficiet match value in described predetermined solvent；

Correspondingly, by described at least 3 kinds of cycloalkane in described predetermined solvent dilution activity coefficiet reason Opinion value and described at least 3 kinds of cycloalkane dilution activity coefficiet literature value in described predetermined solvent are carried out Matching, obtains the Empirical Equation of cycloalkane dilution activity coefficiet match value in described predetermined solvent；

Step d, from alkane/cycloalkane system, determine that alkane to be separated and cycloalkane are respectively as the first alkane Hydrocarbon and the first cycloalkane, obtain respectively described first alkane and the chemical potential of described first cycloalkane and they Chemical potential in described predetermined solvent, and then obtain described first alkane respectively and described first cycloalkane exists Dilution activity coefficiet theoretical value in described predetermined solvent, then utilizes described alkane described predetermined molten The Empirical Equation of the dilution activity coefficiet match value in agent and described cycloalkane are in described predetermined solvent In the Empirical Equation of dilution activity coefficiet match value, respectively obtain described first alkane and described One cycloalkane dilution activity coefficiet match value in described predetermined solvent；

Step e, the infinite dilution in described predetermined solvent according to described first alkane and described first cycloalkane Activity coefficient match value, utilizes relative volatility computing formula, obtains described first alkane and described first ring Alkane relative volatility in described predetermined solvent；

Step f, when described first alkane and described first cycloalkane the relative volatility in described predetermined solvent During more than or equal to 1.2, carry out step g；

When described first alkane and described first cycloalkane, the relative volatility in described predetermined solvent is less than 1.2 Time, re-start step a to step e, until described first alkane and described first cycloalkane are described predetermined Relative volatility in solvent is more than or equal to 1.2；

Described step g includes: according to described first alkane and the chemical potential of described first cycloalkane and they Chemical potential in described predetermined solvent, utilizes Calculation of Solubility formula, respectively obtain described first alkane and Described first cycloalkane dissolubility in described predetermined solvent, when described first alkane and described first cycloalkanes When hydrocarbon dissolubility in described predetermined solvent is all higher than equal to 0.3g/g solvent, determine that described predetermined solvent is Separate described first alkane and the solvent of described first cycloalkane.

Method the most according to claim 1, it is characterised in that in described step a, described solvent divides The synthesis group of son is made up of backbone radical and functional group；

Described backbone radical includes: CH₃、CH₂、CH、C、Cy-CH₂、Cy-CH、Cy-C、ACH、 AC、ACCH3、ACCH₂Or ACCH, wherein, Cy is cycloalkyl group, and A is phenyl；

Described functional group includes: OH, CH₃CO、CH₂CO、CH₃COO、CH₂COO、HCOO、 CH-O、CH₂NH₂、CHNH₂、CHNH₂、CN、CNH₂、CH₃NH、CH₂NH、CHNH、 CH₃N、CH₂N、CH₂CN、COOH、CH₂NO₂、CH₂SH、HCON(CH₂)₂、CON(CH₃)₂、 CON(CH₂)₂、CON(CH₂)CH、CONHCH₃、Cy-CH₂OCH₂、Cy-CONCH₃、 Cy-CONCH₂、Cy-CONCH、Cy-CONC、ACOH、ACNH₂, ACH-N=ACH, AC-N=ACH or AC-N=AC, wherein, Cy is cycloalkyl group, and A is phenyl.

Method the most according to claim 2, it is characterised in that in described predetermined solvent, described function The number of group is 1 or 2.

Method the most according to claim 1, it is characterised in that in described step b, described the dilutest Releasing activity coefficient computing formula is:

$1n{\mathrm{\γ}}_i=({\mathrm{\μ}}_i^{\left(S\right)}-{\mathrm{\μ}}_i^{\left(P\right)})/\mathrm{RT}$

Wherein, γ_iFor component i dilution activity coefficiet theoretical value in a solvent,For component i molten Chemical potential in agent,For the chemical potential of component i, R is gas constant: 8.314J/mol K, T are temperature Degree, unit is K.

Method the most according to claim 4, it is characterised in that in described step c, by described infinitely Dilution activity coefficient theoretical value is as abscissa, using described dilution activity coefficiet literature value as abscissa, Carry out described matching by method of least square, obtain the empirical correlation of described dilution activity coefficiet match value Formula；

The Empirical Equation of described dilution activity coefficiet match value is:

$1n{\mathrm{\γ}}_{\mathrm{correlated}}^{\∞}=a+b\·1n{\mathrm{\γ}}_i^{\∞}+c\·{\left(1n{\mathrm{\γ}}_i^{\∞}\right)}^2+d\·{\left(1n{\mathrm{\γ}}_i^{\∞}\right)}^3+e\·{\left(1n{\mathrm{\γ}}_i^{\∞}\right)}^4$

Wherein, a, b, c, d, e are the constant determined by described matching,For component i in a solvent Dilution activity coefficiet theoretical value,For the dilution activity coefficiet matching in a solvent of component i Value.

Method the most according to claim 5, it is characterised in that in described step e, described waves relatively Sending out degree computing formula is:

${\mathrm{\α}}_{\mathrm{ij}}=\frac{{\mathrm{\γ}}_{i-\mathrm{correlated}}^{\∞}{P_i}^S}{{\mathrm{\γ}}_{j-\mathrm{correlated}}^{\∞}{P}_j^S}$

Wherein, α_ijFor component i and component j relative volatility in a solvent,For component i molten Dilution activity coefficiet match value in agent,For the saturated vapour pressure of component i,For component j Dilution activity coefficiet match value in a solvent,Saturated vapour pressure for component j.

Method the most according to claim 6, it is characterised in that described Calculation of Solubility formula is:

${\log }_{10}\left(x_i\right)={\log }_{10}\left[\exp (({\mathrm{\μ}}_i^{\left(P\right)}-{\mathrm{\μ}}_i^{\left(S\right)}-\mathrm{\Δ}{G}_{i,\mathrm{fusion}})/\mathrm{RT})\right]$

Wherein, x_iFor component i dissolubility in a solvent,For the chemical potential of component i,For component i Chemical potential in a solvent, Δ G_i,fusionFor the melted free energy of component i, being 0 during liquid phase, R is gas constant: 8.314J/mol K, T are temperature, and unit is K.