Juha-Pekka Pokki

Vapour–liquid equilibrium for the 1-butene + methanol, + ethanol, + 2-propanol, + 2-butanol and + 2-methyl-2-propanol systems at 326 K

An automated static total pressure measurement apparatus was used to measure isothermal vapor−liquid equilibria for five binary systems:  trans-2-butene + methanol, + ethanol, + 2-propanol, + 2-butanol, and + 2-methyl-2-propanol at 332.3 K. Error analysis of the measured results has been presented. All systems exhibited positive deviation from Raoults law. The trans-2-butene + methanol and trans-2-butene + ethanol systems showed azeotropic behavior.

spinal Hyperbaric Ropivacaine-fentanyl for Day-surgery

Background: Adequate intraoperative analgesia combined with faster mobilization might be achieved by replacing hyperbaric ropivacaine partly with fentanyl. Methods: Sixty spinal anesthesia patients were randomized into 2 groups of either fentanyl 20 μg mixed with hyperbaric ropivacaine 10 mg (group FR10) or hyperbaric ropivacaine 15 mg (group R15). Forty-five patients underwent inguinal hernia repair and 15 patients had lower extremity surgery. Sensory block was tested by pinprick, and motor block was tested by use of a modified Bromage scale at 5-minute intervals for 30 minutes, 15-minute intervals for 60 minutes, and at 30-minute intervals until full recovery. Results: The groups did not differ significantly regarding success (27 of 30 [group FR10] and 29 of 30 [group R15]), median onset time (10 [5 to 25] v 10 [5 to 20] minutes) or median duration of T10 sensory block (55 [20 to 115] v 80 [5 to 170] minutes), respectively. Recovery from spinal block was significantly quicker in group FR10 than in group R15, recorded in ability to walk (2.5 hours v 3 hours [P = .017]), full motor recovery (1 hour v 1.5 hour [P < .001]), and sensory recovery to S1 (2.5 hours v 3.3 hours [P = .026]). Pruritus occurred in 18 (60%) of group FR10 v 0 of group R15 patients (P < .001). This symptom was mild in all except 1 patient, who received ondansetron 8 mg IV. In the OR, the groups did not differ hemodynamically: 9 (30%) of the group FR10 and 10 (33%) of the group R15 patients, respectively, required medication for hypotension and/or bradycardia. Full motor block (Bromage 3) developed less frequently (P < .001) in group FR10 patients than in group R15 patients (1 [3%] v 14 [47%]), and the group FR10 patients recovered faster in a median time of 60 v 90 minutes (P < .001). In both groups, sensory and motor blocks were more extensive on the operative side compared with the nonoperative side (P < .001). Conclusion: Faster mobilization but equal onset and duration of analgesia were achieved with intrathecal hyperbaric ropivacaine 10 mg plus fentanyl 20 μg as compared with hyperbaric ropivacaine 15 mg.

Solubility of Organosolv Lignin in γ-Valerolactone/Water Binary Mixtures.

Abstract The solubility of lignin in a mixture of γ‐valerolactone (GVL) and water at different weight ratios was measured using the Hildebrand solubility parameters. Based on the molecular structure of lignin, its solubility parameter (δ‐value) was calculated as 25.5 MPa1/2. The δ‐value for aqueous GVL solvent increased from 23.1 MPa1/2 for pure GVL to 45.6 MPa1/2 for pure water. Therefore, the lignin solubility was predicted to increase with increasing GVL concentration in the aqueous mixture up to approximately 92–96 wt % of GVL. A ternary diagram describing the phase behavior of water–GVL–lignin mixtures at room temperature was constructed based on the experimental results. The three‐component system exhibited a complex behavior with a liquid–liquid and solid–liquid–liquid phase split. The efficiency of the selected fractionation trials in a previous work was validated using the ternary solubility diagram. A promising recovery pathway and lignin isolation method were deduced from the results of this work.

Chemical recovery of γ-valerolactone/water biorefinery

We introduce the optimization of the pulping conditions and propose different chemical recovery options for a proven biorefinery concept based on γ-valerolactone (GVL)/water fractionation. The pulping process has been optimized whereby the liquor-to-wood (L:W) ratio could be reduced to 3 L/kg without compromising the pulp properties as raw material for textile fibers production. The recovery of the pulping solvent was performed through combinations of lignin precipitation by water addition, distillation at reduced pressure, and liquid CO2 extraction. With a two-step lignin precipitation coupled with vacuum distillation, more than 90% of lignin and GVL could be recovered from the spent liquor. However, a significant part of GVL remained unrecoverable in the residue, which was a highly viscous liquid with complicated phase behavior. The recovery by lignin precipitation combined with liquid CO2 extraction could recover more than 85% GVL and 90% lignin without forming any problematic residue as in the distillation process. The remaining GVL remained in the raffinate containing a low amount of lignin and other compounds, which can be further processed to isolate the GVL and improve the recovery rate.