Production of Linear Alkybenzene Sulfonic Acid (LAS)

115 Pages·2010·4.44 MB·English

Production of Linear Alkybenzene Sulfonic Acid (LAS)
at High Pressure in Supercritical Carbon Dioxide
Medium

by

Mohammad Basry Attar

A thesis
presented to the University of Waterloo
in fulfillment of the
thesis requirement for the degree of
Master of Applied Science
in
Chemical Engineering

Waterloo, Ontario, Canada, 2010
© Mohammad Basry Attar 2010
I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis,
including any required final revisions, as accepted by my examiners.

I understand that my thesis may be made electronically available to the public.

ii
Abstract
Linear Alkyl benzene Sulfonic Acid (LAS) is the main ingredient of many commercial
formulations for industrial and domestic synthetic detergents. The current industrial LAS
production method includes sulfonation of linear alkylbenzene (LAB) with sulfur trioxide
in tubular falling film reactors. In such reactors a diluted gaseous stream of SO and dry
3
air, feed gas, is contacted with liquid LAB while both reactants flow co-currently
downward. The reaction is highly exothermic and product quality is primarily dependent
on heat removal efficiency from the reactors, and also contact time.
This research project investigates a new route for the production of LAS. This new
method employs SO oxidation over activated carbon at 25oC to SO , followed by the
2 3
extraction of the adsorbed SO from the activated carbon by supercritical carbon dioxide
3
(SCCO ). The condensed phase CO -SO mixture after expansion is contacted with LAB
2 2 3
where sulfonation of this substrate occurs to yield LAS. The new route should offer lower
operating temperatures and lower feed gas SO concentrations in the sulfonation reaction to
3
minimize loss of LAB to side-reactions and reduce LAS contamination (that appears as
unacceptable product discoloration).
The laboratory set up was designed, assembled and in total 25 experiments were carried
out. Over the course of experiments a number of remedial actions were taken to improve
set up functionality and reaction yield. The problems needed to be tackled included feed
gas moisture removal, SO /SO adsorption/desorption efficiency, homogeneous mixing
2 3
of reactants and reducing the SCCO /SO flow rate through LAB columns.
2 3
The maximum LAB/LAS conversion obtained was 3.6 % per sulfonation column. The
maximum SO removal efficiency from activated carbon obtained was 77%.
3
It was also found that nitrogen gas in a specific temperature range may be used as the
desorbing agent in lieu of supercritical carbon dioxide with satisfactory performance.
As supplementary data, the Brauner-Emmet-Teller surface area of activated carbon type
BPL 6x16 from “Calgon Carbon Corporation” was measured.

iii
Acknowledgements

I would like to express my sincere gratitude to my research supervisors, Professors Peter
Silveston, Ali Lohi, Robert Hudgins, Eric Croiset and William Epling for their valuable
guidance, support and patience throughout this project.
I wish to express great appreciation to Prof. Peter Silveston for providing funding and
support for this research project.
My special thanks to Prof. Ali Lohi for his generous guidance and advice throughout the
entire project.
I wish to acknowledge the contribution of “CEPSA Química Bécancour Inc.”, Quebec,
for donating LAB samples used in this research.
I would like to appreciate the contribution of “Calgon Carbon Corporation”, for donating
activated carbon samples used in this research.
I would like to acknowledge the contribution of “Mott Corporation”, for donating gas
diffusers used in this research.

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Table of Contents

List of Tables viii
List of Figures ix
Chapter 1 Introduction…………………………………………………………..…… 1
Chapter 2 Literature Review ……………………………………………………….…3
2.1Reactions at High Pressure………………………………………………..…...........3
2.1.1 Considerations of Reaction at High Pressure ………………..…………...…3
2.1.2 Molecular Theory of Reactions at High Pressure ………..…………...........4
2.2 Super-Critical Carbon Dioxide Properties and Effects on Reactions……………....6
2.2.1 Supercritical Carbon Dioxide Properties …………………………………..6
2.2.2 Effects of Supercritical Carbon Dioxide on Reactions ………………..…....9
2.3 Anionic Surfactant Production ……………………………………………….…...12
2.3.1 Linear Alkylbenzne (LAB) and Linear Alkylbenzen Sulfonic Acid ……...12
2.3.2 LAB Sulfonation in Falling Film Reactors……………….………………..14
2.4 Analytical ……………………………………………..…………………….…….16
Chapter 3 Experimental Apparatus…………………………………………..…. ….18
3.1 Experimental Set up..………………………………………………………..…....18
3.2 Experimental Procedures ….……………………………………………………..26
3.2.1 Oxidation Process……………………………….………………………... 26
3.2.2 SO Desorption from Activated Carbon……………………………..…….31
3
3.2.3 LAB Sulfonation reaction ………………………………………………....35
v
3.2.4 Activated Carbon Rejuvenation ………………………………………..….39
3.2.5 LAB/LAS Sample Titration………………………………………………..39
Chapter 4 Experimental Methodology and Results Evaluation………...………….40
4.1 Methodology …………………………………………………………...………40
4.2 Results Evaluation……………………………...………………………..……….43
4.2.1 Sulfonation Process ………………………………………………………..44
4.2.1.1 Increasing LAB Column Diameter……………….…………………44
4.2.1.2 Using Back Pressure Regulator with Lower Flow Coefficient …….45
4.2.1.3 Using Needle Valve.….…………………...………………………...45
4.2.1.4 Using Metering Valve……………………………….………………45
4.2.2 Oxidation Process……………………………………..………… ………..45
4.2.2.1 Using Different Types of Activated Carbon…….…………………..45
4.2.2.2 Feed Gas Oxygen Content………………………….……….………46
4.2.2.3 Using De-humidifying Units…………………………..…………….46
4.2.2.4 Different Sizes of Activated Carbon Column………………….……46
4.3 Using Nitrogen gas as desorbing agent and SO carrier …………………………47
3
4.4 BET Results …………………………………………………………………..…48
Chapter 5 Conclusions and Recommendations……………………………………...49
5.1 Conclusions………………………………………………………………...……..49
5.2 Recommendations …………………………………………………………..……50
References………………………………………….………………………...……….…52
Appendices
Appendix A Experimental Data Tables……………………………………………. 55
Appendix B Sample Calculation ……………………………………………….…... 75
Appendix C Analytical Procedure…….……………………………………………..85
vi
Appendix D Supplementary Tables ………….……………………………………..87
Appendix E Supplementary Figures..……………………..…………….…………..91
Appendix F Mass Flow Controller Calibration data………………………….……97
Appendix G BET Results……………………...……………………………………100

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List of Tables

Table 2.1 Density, Pressure and temperature relation for CO ……………………...……8
2
Table 4.1 Final SO mass balance-Summary of the results of experiment No. 25.….…....44
3
Table 4.2 Summary of the results of Nitrogen experiments…..…………..……….…….48
Table A.1 Data and results of experiments No.1 to 5……………………………………55
Table A.2 Data and results of experiments No.6 to 10……….………………………….59
Table A.3 Data and results of experiments No.11 to 15…………………………………63
Table A.4 Data and results of experiments No.16 to 20…………………………………67
Table A.5 Data and results of experiments No.21 to 25…………………………………71
Table B.1 Data and results of experiment No.17………………………………..……….76
Table D.1 Contribution to reactants volume change as they form transition state….…..87
Table D.2 Typical Ingredients of heavy duty laundry detergent …….………...………..87
Table D.3 Specifications of gases used in experiments…….……………………………88
Table D.4 Specifications of high pressure ISCO pump model 260D….………………...89
Table D.5 Specifications of activated carbon type BPL 4x6 …….……………...………90
Table D.6 Specifications of activated carbon type BPL 6x16…….……………..………90

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List of Figures

Figure 2.1 P-T diagram of CO .………………………………………………………….7
2
Figure 2.2 Variation of reduced pressure and density of CO with temperature..……….8
2
Figure 2.3 The molecular structure of Linear Alkylbenzene and linear alkylbenzene
Sulfonic Acid …………………………….…………………………………………..12
Figure 2.4 Sulfonation of linear alkylbenzene to produce linear alkylbenzene Sulfonic
Acid....................................................................................................................................14

Figure 2.5 Primary reaction pathway- LAB reaction with SO …………………………15
3..
Figure 2.6 Main reaction pathway - pyrosulfonic acid acting as sulfonating agent .…....15
Figure 3.1 Schematic of laboratory set up - Sulfonation of linear alkylbenzene ……......19
Figure 3.2 SO Oxidation flow diagram - Sulfonation of linear Alkylbenzene.. ……..…27
2
Figure 3.3 Typical adsorption break-through curve..……………………………...…… 29
Figure 3.4 SO desorption flow diagram - Sulfonation of linear alkylbenzene .………...33
3
Figure 3.5 LAB sulfonation flow diagram - Sulfonation of linear Alkylbenzene……….36
Figure 4.1 Schematic of modified LAB1 column ………….……………………………42
Figure B.1 Adsorption break-through curve obtained in experiment No.17 …………....78
Figure E.1 Solubility of naphthalene in CO as a function of density ………………… 91
2
Figure E.2 Solubility of naphthalene in CO as a function of temperature……………...91
2
Figure E.3 Viscosity behavior of CO at various temperatures and pressures ………….92
2
Figure E.4 Diffusivity of CO at various pressures ………………...…………………...92
2
Figure E.5 By-Products of LAB sulfonation reaction …..………….…...………………93
Figure E.6 Quaternary ammonium slats chemical structure .............................................94
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Figure E.7 Flow characteristic of high pressure pump model ISCO 260 D ………...…. 95
Figure E.8 Analysis Certificate of LAB type P-550………….……….………………...96
Figure F.1 Calibration data of SO mass flow controller…………………….…………..97
2
Figure F2 Calibration data of Air mass flow controller…………………………………98
Figure F3 Calibration data of Nitrogen mass flow controller……………...……………99
x