Title: Sulfolane: Magic Extractor or Bad Actor? Pilot-Scale Study on Solvent Corrosion Potential Author: Andrzej Bąk, Violetta Kozik, Paulina Dybal, Slawomir Kus, Aleksandra Świetlicka, Josef Jampilek Citation style: Bąk Andrzej, Kozik Violetta, Dybal Paulina, Kus Slawomir, Świetlicka Aleksandra, Jampilek Josef. (2018). Sulfolane: Magic Extractor or Bad Actor? Pilot-Scale Study on Solvent Corrosion Potential. “Sustainability” (Vol. 10 (2018), Art. No. 3677), doi 10.3390/su10103677 sustainability Review Sulfolane: Magic Extractor or Bad Actor? Pilot-Scale Study on Solvent Corrosion Potential Andrzej Bak 1,* , Violetta Kozik 1, Paulina Dybal 1, Slawomir Kus 2, Aleksandra Swietlicka 1 and Josef Jampilek 3,* 1 Department of Synthesis Chemistry, Faculty of Mathematics, Physics and Chemistry, University of Silesia, Szkolna 9, 40007 Katowice, Poland; [email protected] (V.K.); [email protected] (P.D.); [email protected] (A.S.) 2 Honeywell Process Solutions, 11201 Greens Crossing Blvd, Suite 700 Houston, TX 77067, USA; [email protected] 3 Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Comenius University, Odbojarov 10, 83232 Bratislava, Slovakia * Correspondence: [email protected] (A.B.); [email protected] (J.J.); Tel.: +48-32-359-1197 (A.B.) Received: 17 September 2018; Accepted: 11 October 2018; Published: 14 October 2018 Abstract: The sulfur-containing derivatives and their metabolites, regarded as ‘old devils of green’ chemistry, constitute a relevant class of air/water/soil contaminants in over-polluted world. In fact, some industrially-engineered solvents have become environmentally unfavorable. An attractive alternative to commonly used industrial liquids is sulfolane (C4H8SO2), an anthropogenic medium. The main objective of this paper is the comprehensive review focusing mainly on the state-of-the-art aspects of the sulfolane synthesis, application of sulfolane as an extractive solvent due to its ‘unique’ physicochemical properties as well as the potential of sulfolane to cause equipment corrosion and subsequent spills. The potential risk for groundwater contamination, danger for human health and ways of sulfolane biodegradation were briefly reviewed as well. Interestingly, the analysis performed on data stored in the Reaxys database revealed an alternating tendency of waxing and waning interest in sulfolane during the space of the last fifty years. Moreover, the primary goal of the presented case study was to verify applicability of industrial, multi-electrochemical technique for reliable detection of corrosion in low conductive process fluids. Several aspects of corrosion measurement including the impact of process parameters (temperature) and impurities (oxygen and chlorides) on stainless steel corrosion in pure sulfolane were investigated briefly. Keywords: sulfolane; aprotic solvent; liquid extraction; biodegradation; on-line corrosion monitoring; electrochemical techniques 1. Introduction Pollutants emitted from certain solids or liquids originate from anthropogenic activity or from the biogenic emissions of certain reactive hydrocarbon derivatives formed as chemical (by-)products of natural transformations [1]. The odor-causing mixtures of sulfur-containing derivatives and their metabolites constitute a main class of irritant and toxic contaminants with increasingly detrimental impact on human health in the long-term exposure, being also classified as a potential mutagenic and carcinogenic risk factors [2,3]. A diverse ‘suite’ of environmental contaminants, potentially resistant to degradation, were designed and engineered for industrially-specific purposes becoming problematic, when released into the Nature since recalcitrance correlates to persistence [4]. On the other hand, natural gases also contain ‘sour’ impurities such as hydrogen sulfide (H2S) or carbon dioxide (CO2), the removal of which is technologically and/or economically relevant to ‘soften’ the Sustainability 2018, 10, 3677; doi:10.3390/su10103677 www.mdpi.com/journal/sustainability Sustainability 2018, 10, 3677 2 of 21 Sustainability 2018, 10, x FOR PEER REVIEW 2 of 22 natural/industrial (off)gases [5,6]. Consequently, the eradication of sulfur-containing compounds 45 technologically(e.g., H2S, COS, and/or mercaptans, economically organic sulfides) relevant from to unprocessed‘soften’ the naturalnatural/industrial gases can be (off)gases performed [5,6]. in the 46 Cliquid-liquidonsequently, extractionthe eradication process, of sul wherefur-containing industrial solventscompounds areused (e.g. inH2 aS, ‘closed’ COS, mercaptans loop, recovered, organic and 47 sulregeneratedfides) fromon-site, unprocessedthat theoretically natural gas preventes can extractorbe performed disposal in the [7, 8li].quid In this-liquid context extraction questions process about, 48 wherethe ‘green’ industrial solvents solvents and manufacturing are used in a procedures ‘closed’ loop, used recovered in the liquid-liquid and regenerated extraction on are-site looked, that 49 theoreticallyupon favourably. prevent extractor disposal [7,8]. In this context questions about the ‘green’ solvents 50 and manufacturingIn fact, a range procedure of solventss canused be in employed the liquid in-liquid the extraction extraction process are looked used inupon oil refiningfavourably. including 51 (di/tri/tetra)In fact, a ethylenerange of glycolsolvents (D/T/TT/EG), can be employed diglycol in the amine extraction (DGA), processn-methyl used pyrolidone in oil refining (NMP), 52 includingdimethylsulphoxide (di/tri/tetra)(DMSO), ethylene dimethylformamideglycol (D/T/TT/EG), (DMF),diglycol morpholine amine (DGA), and carbonaten-methyl pyrolidone derivatives. 53 (NMP),An attractive dimethylsulph alternativeoxide to commonly (DMSO), used dimethylformamide industrial extractive (DMF) liquids, ismorpholine sulfolane, anand anthropogenic carbonate 54 derivatives.organosulfur An medium attractive regarded alternative as toa versatilecommonly dipolar used aprotic industrial solvent extractive[9,10]. Sulfolaneliquids is sulfolane (C4H8SO,2 an) is 55 anthropogenicthe generic name organosul for hydrogenatedfur medium sulfonesregarded of as butadiene a versatile [dipolar11]. In aprotic the present solvent review [9,10]. weSulfolane mainly 56 (Cfocus4H8SO on2) theis the sulfolane generic synthesis, name for application hydrogenated of sulfolane sulfones asof anbutadiene extractive [11]. solvent In the due present to its ‘unique’review 57 wephysicochemical mainly focus on properties the sulfolane as well synthesis, as on the application potential of of sulfolane sulfolane to as cause an extractive equipment solvent corrosion due andto 58 itssubsequent ‘unique’ physicochemical spills. The possible properties risk for as groundwater well as on the contamination, potential of sulfolane danger for to humancause equipment health and 59 corrosionways of sulfolane and subsequent biodegradation spills. areThe reviewed possible briefly risk asfor well. groundwater Interestingly, contamination, the analysis performeddanger for on 60 humandata stored health in and the Reaxysways of databasesulfolane revealed biodegradation an alternating are reviewed tendency briefly of waxing as well. and Interestingly, waning interest the 61 analysisin sulfolane performed during on the data space stored of the in last the fifty Reaxys years. database Roughly revealed speaking, an the alternating revealed ‘wavy’tendency trends of 62 waxingin sulfolane and waning interests interest provide in ansulfolane illustration during of the the partial space correlationsof the last fifty with years oil prices.. Roughly Moreover, speaking, the 63 theprimary revealed goal ‘wavy’ of the presentedtrends in casesulfolane study wasinterests to verify provide applicability an illustration of industrial, of the multi-electrochemicalpartial correlations 64 withtechnique oil prices. for reliableMoreover, detection the primary of corrosion goal of the in lowpresented conductive case study process was (sulfolane-based) to verify applicability fluids. 65 ofSeveral industrial, aspects multi of corrosion-electrochemical measurement technique of general for reliable and localized detection corrosion of corrosion modes in werelow conductive investigated 66 processbriefly, (sulfolane since corrosion-based) control fluids. and Several monitoring aspects inof sulfolanecorrosion unitsmeasurement does not of find general prominent and localized presence 67 corrosionin published modes literature. were investigated Incipient attempts briefly, to since quantify corrosion impact control of process and parametersmonitoring (temperature)in sulfolane 68 unitsand impuritiesdoes not find (oxygen prominent and chlorides) presence on in stainless published steel literature (UNS S304033). Incipient corrosion attempts in pure to quantify sulfolane 69 impactprovided of process reasonably parameters meaningful (temperature) data and and are detailedimpurities elsewhere (oxygen inand this chlorides) paper. For on thestainless purpose steel of 70 (UNSthe proposed S304033) investigationscorrosion in pure a dedicated sulfolane testing provided vessel reasonably was designed meaning andful constructed. data and are It shoulddetailed be 71 elsewhereemphasized in thatthis therepaper. is For a clear the absence purpose of of detailed the proposed and quantitative investigations evaluation a dedicated of individual testing sulfolane vessel 72 wasimpurities designed (like and water, constructed. chlorides, It should etc.), their be emphasized