Supporting Information for

Green Synthesis of Double Long-Chain Diglycerol Diacetal and Its Application as Lubricating Base Oil

Xu Li, Li Chen, Lan Wu, Hong Xu, Jinxiang Dong*

Research Institute of Special Chemicals,College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China

*Corresponding author. Tel.: +86-0351-6111178; Fax: +86-0351-6111178. E-mail:

Contents

Fig. S1.GC/MS spectra of the regioisomer A of diglycerol diacetal………….PageS3

Fig. S2.GC/MS spectra of the regioisomer B of diglycerol diacetal………….PageS3

Fig. S3.GC/MS spectra of the regioisomer C of diglycerol diacetal………….PageS4

Fig. S4.GC/MS spectra of the regioisomer D of diglycerol diacetal………….PageS4

Fig. S5.GC/MS spectra of the regioisomer E of diglycerol diacetal…………..PageS5

Fig. S6.GC/MS spectra of the regioisomer F of diglycerol diacetal…………..PageS5

Fig. S7.Photograph and schematic of a stationary disk and a reciprocating ball under applied loads(Left); Table of operating conditions and test specimens used in tribological tests(Right).……………………………………………………...PageS6

Table S1. Friction and wear results under lubrication of oils investigated in this study…………………………………………………………………………....PageS7

Fig. S8.Primary biodegradation of diglycerol diacetal………………………..PageS9

1. GC/MS spectra of the regioisomers of diglycerol diacetal

Fig.S1. GC/MS spectra of the regioisomer A of diglycerol diacetal (Horizontal axis: m/z;Vertical axis: Relative abundance; Base peak: 343; M-1: 497).

Fig. S2. GC/MS spectra of the regioisomer B of diglycerol diacetal (Horizontal axis: m/z;Vertical axis: Relative abundance; Base peak: 343; M-1: 497).

Fig. S3. GC/MS spectra of the regioisomer C of diglycerol diacetal (Horizontal axis: m/z;Vertical axis: Relative abundance; Base peak: 343; M-1: 497).

Fig. S4. GC/MS spectra of the regioisomer D of diglycerol diacetal (Horizontal axis: m/z;Vertical axis: Relative abundance; Base peak: 343; M-1: 497).

Fig. S5. GC/MS spectra of the regioisomer E of diglycerol diacetal (Horizontal axis: m/z;Vertical axis: Relative abundance; Base peak: 343; M-1: 497).

Fig. S6. GC/MS spectra of the regioisomer F of diglycerol diacetal (Horizontal axis: m/z;Vertical axis: Relative abundance; Base peak: 343; M-1: 497).

2. Supplementary methods and results in tribological tests

Fig. S7.Photograph and schematic of a stationary disk and a reciprocating ball under applied loads(Left); Table of operating conditions and test specimens used in tribological tests(Right).

Table S1. Friction and wearresults under lubrication of oils investigated in this study[a]

Base Oil / T321 amount (wt. %) / Applied Load (N) / Mean Friction Coefficient / WSD [b]
(mm) / Wear Volume [c] (×10-4 mm3)
Diglycerol Diacetal / 0 / 150 / 0.093 / 0.48 / 2.24
0 / 200 / 0.093 / 0.50 / 3.19
0.5 / 400 / 0.088 / 0.53 / 2.02
0.5 / 450 / 0.087 / 0.55 / 2.51
PAO 8 / 0 / 150 / 0.184 / 0.56 / 4.00
0 / 200 / Seizure / 0.59 / 7.19
0.5 / 400 / 0.103 / 0.54 / 2.41
0.5 / 450 / Seizure / 0.56 / 20.35

[a] Operating conditions: see Fig. S7. [b] Wear scar diameter of the upper balls. [c]Wear volume of the lower disks.

3. Primary biodegradation of diglycerol diacetal

3.1 Biodegradation test

Biodegradation test was carried outat Key Laboratory of Surfactant, China Research Institute of Daily Chemical Industry. Shaking-flask test for primary aerobic biodegradation was established according to International Standards Organization (ISO) method 7827 [1, 2]. Biodegradation culture media of 0.5L (wastewater, pH is about 7.4) were prepared in 1L shaking flask, containing the following minerals: NH4Cl, 1.5g; K2HPO4, 0.5g; MgSO4, 0.125g; KCl, 0.125g; FeSO4, 0.001g; and yeast extract, 0.15g. Diglycerol diacetal was added to wastewater to give a mass concentration of 30mgL−1. Control was prepared simultaneously. Each flask was inoculated with 5mL of 15gL−1suspended solids containing aerobic activated sludge. The flask was placed on a shaker table in a temperature-controlled cabinet and shaken continuously at 200rpm, 25°C. Then 5mL of twice acclimated solution were transferred into another shaking-flask to degrade diglycerol diacetal.

3.2 Analysis process

Thirty mililiter wastewatersample was withdrawn at regular intervals of time and added to 125 mL separatory funnel. Then the mixture was extracted with 10 mL ethyl acetate . After layer seperation, ethyl acetate extract was washed with brine, dried over Na2SO4 and filtered through a 0.45 μm PTFE hydrophobic membrane to remove moisture and particles.From this prepared solution, a 1.0 μL samplewas injected into a Gas chromatography for analysis.The diglycerol diacetal content in ethyl acetateextract was determined according to the chromatographic peak areas. Reference sample was carried out simultaneously.

Extent of primary biodegradation (η)of diglycerol diacetal was calculated from theequation:η=[(A0−At)/A0]×100%, whereA0istheinitial chromatographic peak areas,Atis the chromatographic peak areas oftdays, andAis calculated fromgas chromatographic peak areas of diglycerol diacetal.

Biodegradation curves of diglycerol diacetal for six days are shown in Fig. S8. Further and detailed studies aboutbiodegradation of diglycerol diacetal are being conducted in this laboratory.

Fig. S8.Biodegradation curves of diglycerol diacetal.

1.Zhao J, Zhang G, Qin Y, Zhao Y (2006) Aerobic biodegradation of alkylphenol ethoxylates. Bioresource Technol 97:2478-2480.

[2]International Standards Organization, ISO 7827-1984(E), 1984. Water quality—evaluation in an aqueous medium of the ultimate aerobic biodegradability of organic compounds—methods by analysis of dissolved organic carbon (DOC). International Standards Organization, Geneva.

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