HIGH-PURITY ISOPROPYL ALCOHOL AND METHOD FOR MANUFACTURING SAME

Abstract

Provided is a high-purity isopropyl alcohol in which the concentration of a C7-12 acetal compound is 100 ppb or less on a mass basis, the concentration of the acetal compound in an accelerated test involving heating for 4 hours at 80° C. in a nitrogen atmosphere is increased by a factor of 30 or less with respect to the value thereof prior to heating, and the concentration of the acetal compound is maintained at a value of 100 ppb or less on a mass basis. Also provided is a method for manufacturing said high-purity isopropyl alcohol.

Claims

1. A cleaning liquid formed of a high-purity isopropyl alcohol and used in a semiconductor manufacturing process, wherein a water content is 3 to 25 ppm by mass, a concentration of an acetal compound having 7 to 12 carbon atoms is equal to or less than 100 ppb by mass, and when an acceleration test for performing heating at 80° C. for 4 hours is performed under a nitrogen atmosphere, an amount of increase in the concentration of the acetal compound is 30 or less times a value before the heating, and the concentration of the acetal compound is maintained to be a value equal to or less than 100 ppb by mass.

2. The cleaning liquid according to claim 1, wherein when an acceleration test for performing heating at 120° C. for 4 hours is performed under a nitrogen atmosphere, an amount of increase in the concentration of the acetal compound is 30 or less times the value before the heating, and the concentration of the acetal compound is maintained to be a value equal to or less than 100 ppb by mass.

3. The cleaning liquid according to claim 1, wherein a concentration of an aldehyde compound having 1 to 6 carbon atoms is equal to or less than 1500 ppb by mass.

4. The cleaning liquid according to claim 1, wherein a concentration of a ketone compound having 3 to 6 carbon atoms is equal to or less than 2000 ppb by mass.

5. (canceled)

6. (canceled)

7. A method for manufacturing the high-purity isopropyl alcohol in which a concentration of an acetal compound having 7 to 12 carbon atoms is equal to or less than 100 ppb by mass, and in which when an acceleration test for performing heating at 80° C. for 4 hours is performed under a nitrogen atmosphere, an amount of increase in the concentration of the acetal compound is 30 or less times a value before the heating and the concentration of the acetal compound is maintained to be a value equal to or less than 100 ppb by mass, the method comprising: a reduced-pressure distillation step of distilling a low-boiling portion by reduced-pressure distillation so as to perform purification until a concentration of an aldehyde compound having 1 to 6 carbon atoms is reduced to be equal to or less than 1500 ppb by mass; and an atmospheric distillation step of removing a bottom liquid by atmospheric distillation so as to perform purification until the concentration of the acetal compound having 7 to 12 carbon atoms is reduced to be equal to or less than 100 ppb by mass, wherein the reduced-pressure distillation step and the atmospheric distillation step are combined to be performed on crude isopropyl alcohol.

8. The method for manufacturing the high-purity isopropyl alcohol according to claim 7, wherein in the reduced-pressure distillation step, purification is performed such that a concentration of a ketone compound having 3 to 6 carbon atoms is reduced to be equal to or less than 2000 ppb by mass.

9. The method for manufacturing the high-purity isopropyl alcohol according to claim 7, wherein the crude isopropyl alcohol is obtained by a direct hydration method of propylene.

Description

EXAMPLES

[0081] Although the present invention will be more specifically described below using Examples, the present invention is not limited to these Examples.

[0082] The analytical and quantitative methods of the impurities and the like will first be described.

(Measurement Method of Acetal Compound; Qualitative Analysis)

[0083] An acetal compound included in isopropyl alcohol was measured with GC-MS under measurement conditions shown below.

—Measurement Conditions—

[0084] Device: 7890A/5975C (made by Agilent Technologies, Inc.)

[0085] Analytical column: SUPELCO WAX-10 (60 m×0.25 mm, 0.25 μm)

[0086] Column temperature: 35° C. (held for 2 minutes).fwdarw.temperature rise at 5° C./minute.fwdarw.100° C..fwdarw.temperature rise at 10° C./minute.fwdarw.240° C. (held for 6 minutes)

[0087] Carrier gas: helium

[0088] Carrier gas flow rate: 2 mL/minute

[0089] Injection port temperature: 240° C.

[0090] Sample injection method: pulsed splitless method

[0091] Pulse pressure at time of injection: 90 psi (2 minutes)

[0092] Split vent flow rate: 50 mL/minute (2 minutes)

[0093] Use of gas saver: 20 mL/minute (5 minutes)

[0094] Transfer line temperature: 240° C.

[0095] Ion source, quadrupole temperature: 230° C., 150° C.

[0096] Scan ion: m/Z=25 to 250

[0097] When isopropyl alcohol was not concentrated, if in a chart obtained according to the conditions described above, no peak was detected in a region where a holding time was long as compared with isopropyl alcohol, the concentration of the acetal compound can be evaluated to be equal to or less than 500 ppb, which is a detection lower limit.

(Measurement Method of Acetal Compound; Quantitative Analysis)

[0098] When a peak was confirmed in a chart obtained according to the method of the qualitative analysis described above, a library search was made from the mass spectrum of the peak, and thus a structure was identified. Then, the standard substance of the identified acetal compound was prepared, a comparison was made with the pre-quantified peak area of the standard substance and thus the concentration of the acetal compound detected by the qualitative analysis was quantified by a selective ion detection method (SIM).

—SIM Monitor Ion—

[0099] Group 1 start time: 12.7 minutes, m/Z: 101, 131, 145 (Duel 60)

(Measurement Method of Aldehyde Compound; Qualitative Analysis)

[0100] An aldehyde compound included in isopropyl alcohol was measured with GC-MS under measurement conditions shown below.

—Measurement Conditions—

[0101] Device: 7890A/5975C (made by Agilent Technologies, Inc.)

[0102] Analytical column: SUPELCO WAX-10 (60 m×0.25 mm, 0.25 μm)

[0103] Column temperature: 35° C. (held for 2 minutes).fwdarw.temperature rise at 5° C./minute.fwdarw.100° C..fwdarw.temperature rise at 10° C./minute.fwdarw.240° C. (held for 6 minutes)

[0104] Carrier gas: helium

[0105] Carrier gas flow rate: 2 mL/minute

[0106] Injection port temperature: 240° C.

[0107] Sample injection method: split method

[0108] Split ratio: 1:10

[0109] Transfer line temperature: 240° C.

[0110] Ion source, quadrupole temperature: 230° C., 150° C.

[0111] Scan ion: m/Z=25 to 250

[0112] When isopropyl alcohol was not concentrated, if in a chart obtained according to the conditions described above, no peak was detected in a region where a holding time was short as compared with isopropyl alcohol, the concentration of the aldehyde compound can be evaluated to be equal to or less than 5000 ppb, which is a detection lower limit.

(Measurement Method of Aldehyde Compound; Quantitative Analysis)

[0113] When a peak was confirmed in a chart obtained according to the method of the qualitative analysis described above as in the quantitative analysis of the acetal compound, a library search was made from the mass spectrum of the peak, and thus a structure was identified. Then, the standard substance of the identified aldehyde compound was prepared, a comparison was made with the pre-quantified peak area of the standard substance and thus the concentration of the aldehyde compound detected by the qualitative analysis was quantified by the selective ion detection method (SIM).

—SIM Monitor Ion—

[0114] m/Z: 29 (acetaldehyde analysis)

[0115] m/Z: 58 (acetone, propionaldehyde analysis)

[0116] m/Z: 72 (butyraldehyde, methyl ethyl ketone analysis)

(Measurement Method of Water Content)

[0117] Device: Karl Fischer Water Analyzer AQ-7 (made by HIRANUMA Co., Ltd.)

[0118] Method: 0.25 g of a measurement sample and 0.75 g of dehydrated acetonitrile were mixed in a glove box whose dew point was equal to or less than −80° C. 0.5 g of the mixed solution was collected with a Terumo Syringe (product name, 2.5 mL) sufficiently dried in the glove box and a measurement was made with the Karl Fischer Water Analyzer.

Example 1

[0119] Isopropyl alcohol for electronic industry made by Tokuyama Corporation (in which a bottom liquid was removed by atmospheric distillation) was prepared, and a distillation operation described below was performed.

(Distillation Operation)

[0120] A flask of 2 L was put into a water bath, and a packed tower whose length was 2 m and in which glass beads were put was installed. 2 L of isopropyl alcohol was put into the flask. The pressure was reduced to 5 kPa, and distillation was performed under conditions in which the water bath had a temperature of 50° C., the temperature of a tower top was 15 to 25° C. and the temperature of a cooler was −5 to 0° C. When after the distillation operation, a measurement was made according to the measurement method of the aldehyde compound described above, as the aldehyde compound, acetaldehyde, propionaldehyde and butyraldehyde were detected. The concentration of the total of acetaldehyde, propionaldehyde and butyraldehyde was equal to or less than 100 ppb. It can be thought that acetaldehyde, propionaldehyde and butyraldehyde were discharged to the outside of the system without being condensed.

[0121] Furthermore, a water content included in the isopropyl alcohol purified by the distillation operation was 5 ppm. A free acid (calculated as acetic acid) included in the isopropyl alcohol was 2 ppm.

[0122] Then, in order to check the storage stability of the isopropyl alcohol purified by the distillation operation, an acceleration test was performed under conditions shown below.

(Acceleration Test)

[0123] 10 mL of a sample which was obtained by distillation and in which the concentration of the total of acetaldehyde, propionaldehyde and butyraldehyde was equal to or less than 100 ppb was put into a SUS pipe of about 20 mL, and nitrogen was supplied at a rate of 100 mL/minute for 30 minutes so as to perform deoxidizing. After the deoxidizing, the SUS pipe was hermetically sealed such that oxygen was prevented from entering the SUS pipe. The SUS pipe was heated with an oil bath of 120° C. for 4 hours. When after the completion of the acceleration test, a measurement was made according to the measurement method of the acetal compound described above, the concentration of the acetal compound was 20 ppb (table 1).

[0124] As described above, in the isopropyl alcohol in which the concentration of the total of acetaldehyde, propionaldehyde and butyraldehyde was reduced to 100 ppb or less, the concentration of the acetal compound was 20 ppb even after the acceleration test, and thus excellent long-term storage stability was shown.

Comparative Example 1

[0125] Isopropyl alcohol for industry made by Tokuyama Corporation was prepared, the same acceleration test as in Example 1 was performed except that acetaldehyde, propionaldehyde and butyraldehyde were not distilled, and the evaluation of the acetal compound was performed. Consequently, the concentration of the acetal compound was increased to 2000 ppb (table 1).

[0126] As described above, in the isopropyl alcohol in which the concentration of acetaldehyde, propionaldehyde and butyraldehyde was not reduced, as a result of the acceleration test, the concentration of the acetal compound reached 2000 ppb, and thus long-term storage stability was poor.

TABLE-US-00001 TABLE 1 Total concentration Total Total of acetal concentration concentration compound after Water of aldehyde of acetal acceleration content compound compound test of 120° C. (ppm) (ppm) (ppm) (ppm) Example 1 5 0.1 or less 0.02 0.02 Comparative 5 5 0.02 2 Example 1

Example 2

(Manufacturing of Crude Isopropyl Alcohol)

[0127] As propylene serving as a raw material, propylene which included, as impurities, 39972 ppm of propane, 20 ppm of ethane, 8 ppm of butene, 0.1 ppm or less of pentene and 0.1 ppm or less of hexene was prepared. As water serving as a raw material, water whose pH was adjusted to be 3.0 by the addition of phosphor tungstic acid serving as an acid catalyst was prepared. The water heated to 110° C. was charged into a reactor having an internal volume of 10 L at a supply rate of 18.4 kg/h (20 L/h because the density was 920 kg/m.sup.3), and the propylene was charged thereinto at a supply rate of 1.2 kg/h.

[0128] A reaction temperature within the reactor was set to 280° C., a reaction pressure was set to 250 atm and the propylene and the water were made to react with each other so as to obtain isopropyl alcohol. A reaction product including the generated isopropyl alcohol was cooled to 140° C., the pressure was reduced to 18 atm and thus the propylene dissolved in the water included in the reaction product was recovered as gas. The recovered propylene was charged into a recovery drum for propylene in order to be recycled as the raw material. Here, a conversion rate of the supplied propylene was 84.0%, and a selection rate of the propylene to the isopropyl alcohol was 99.2%.

[0129] Then, dehydration was performed by distillation, and thus crude isopropyl alcohol in which the concentration of isopropyl alcohol was 99 was obtained. For the obtained crude isopropyl alcohol, the concentrations of the acetal compound, the aldehyde compound and the ketone compound were measured, and the results thereof are shown in table 2.

TABLE-US-00002 TABLE 2 Concentrations in crude isopropyl alcohol (ppb) C7-C12 acetal C8 acetal 200 compound C9 acetal 200 Other acetals 20 Acetal compound total 420 C1-C6 aldehyde Acetaldehyde 1000 compound Propionaldehyde 2000 Butyraldehyde 500 Aldehyde compound total 3500 C3-C6 ketone Acetone 500 compound 2-Pentanone 1000 3-Methyl-2-pentanone 500 Ketone compound total 2000

(Purification of Crude Isopropyl Alcohol)

[0130] A flask of 2 L was put into a water bath, and a packed tower (the corresponding number of plates by conversion to the plate tower was 10) whose length was 2 m and in which glass beads were put was prepared. 2 L of the crude isopropyl alcohol was put into the flask. Reduced-pressure distillation was performed under conditions in which the pressure was 20 kPa, a reflux ratio was 3, the temperature of the water bath was 70° C., the temperature of a tower top was 35 to 45° C. and the temperature of a cooler was −5 to 0° C., with the result that a low-boiling portion was distilled. Then, as in the same manner as described above, a flask of 2 L was put into a water bath, and a distillation tower (the corresponding number of plates by conversion to the plate tower was 20) whose length was 3 m and in which glass beads were put was prepared. The isopropyl alcohol obtained by reduced-pressure distillation was put into the flask. Atmospheric distillation was performed under conditions in which a reflux ratio was 3, the temperature of an oil bath was 120° C., the temperature of a tower top was 82° C. and the temperature of a cooler was 25° C. When the concentration of the isopropyl alcohol in a distilled liquid was measured with GC/MS, the concentration of the isopropyl alcohol excepting water was so highly pure as to be equal to or greater than 99.999%. For the obtained high-purity isopropyl alcohol, the concentrations of the acetal compound, the aldehyde compound and the ketone compound were measured, and the results thereof are shown in tables 3 to 5. For the obtained high-purity isopropyl alcohol, a water content was measured, and the result thereof is also shown in table 3.

(Acceleration Test)

[0131] On the high-purity isopropyl alcohol obtained as described above, in the same manner as in Example 1, an acceleration test at a heating temperature of 80° C. was performed, and the evaluation of the acetal compound was performed. Consequently, the concentration of the acetal compound was 90 ppb (table 6). Aside from this test, an SUS pipe in which the high-purity isopropyl alcohol was stored was stored under room temperature (25° C.) for 6 months, and the acetal compound was measured, with the result that the concentration thereof was 85 ppb. Hence, it can be confirmed that the acceleration test at 80° C. is substantially comparable to the severity against the increasing action of the acetal compound received by isopropyl alcohol when the isopropyl alcohol is stored under room temperature (25° C.) in the dark for 6 months.

[0132] Furthermore, when the same acceleration test (except that the heating temperature in the oil bath of the SUS pipe was changed to 120° C.) was performed, the concentration of the acetal compound was 350 ppb (table 7).

Example 3

[0133] In the same manner as in Example 2 except that the conditions of reduced-pressure distillation in Example 2 (purification of crude isopropyl alcohol) were changed to conditions in which the pressure was 10 kPa, the reflux ratio was 3, the temperature of the water bath was 70° C., the temperature of the tower top was 28 to 38° C. and the temperature of the cooler was −5 to 0° C., a high-purity isopropyl alcohol in which the concentration of isopropyl alcohol excepting water was equal to or greater than 99.999% was manufactured. For the obtained high-purity isopropyl alcohol, the concentrations of the acetal compound, the aldehyde compound and the ketone compound were measured, and the results thereof are shown in tables 3 to 5. For the obtained high-purity isopropyl alcohol, a water content was measured, and the result thereof is also shown in table 3.

(Acceleration Test)

[0134] On the high-purity isopropyl alcohol obtained as described above, in the same manner as in Example 1, acceleration tests under temperature conditions of 80° C. and 120° C. were performed, and the evaluation of the acetal compound was performed. Consequently, the concentration of the acetal compound was 40 ppb (table 6) at 80° C. and was 85 ppb (table 7) at 120° C.

Example 4

[0135] In the same manner as in Example 2 except that the conditions of reduced-pressure distillation in Example 2 (purification of crude isopropyl alcohol) were changed to conditions in which the pressure was 5 kPa, the reflux ratio was 6, the temperature of the water bath was 50° C., the temperature of the tower top was 15 to 25° C. and the temperature of the cooler was −5 to 0° C., a high-purity isopropyl alcohol in which the concentration of isopropyl alcohol excepting water was equal to or greater than 99.999% by mass was manufactured. For the obtained high-purity isopropyl alcohol, the concentrations of the acetal compound, the aldehyde compound and the ketone compound were measured, and the results thereof are shown in tables 3 to 5. For the obtained high-purity isopropyl alcohol, a water content was measured, and the result thereof is also shown in table 3.

(Acceleration Test)

[0136] On the high-purity isopropyl alcohol obtained as described above, in the same manner as in Example 1, acceleration tests under temperature conditions of 80° C. and 120° C. were performed, and the evaluation of the acetal compound was performed. Consequently, the concentration of the acetal compound was 19 ppb (table 6) at 80° C. and was 27 ppb (table 7) at 120° C.

Example 5

[0137] In the same manner as in Example 2 except that the conditions of reduced-pressure distillation in Example 2 (purification of crude isopropyl alcohol) were changed to conditions in which the pressure was 5 kPa, the reflux ratio was 9, the temperature of the water bath was 50° C., the temperature of the tower top was 15 to 25° C. and the temperature of the cooler was −5 to 0° C., a high-purity isopropyl alcohol in which the concentration of isopropyl alcohol excepting water was equal to or greater than 99.999% by mass was manufactured. For the obtained high-purity isopropyl alcohol, the concentrations of the acetal compound, the aldehyde compound and the ketone compound were measured, and the results thereof are shown in tables 3 to 5. For the obtained high-purity isopropyl alcohol, a water content was measured, and the result thereof is also shown in table 3.

(Acceleration Test)

[0138] On the high-purity isopropyl alcohol obtained as described above, in the same manner as in Example 1, acceleration tests under temperature conditions of 80° C. and 120° C. were performed, and the evaluation of the acetal compound was performed. Consequently, the concentration of the acetal compound was 11 ppb (table 6) at 80° C. and was 15 ppb (table 7) at 120° C.

Example 6

[0139] In the same manner as in Example 2 except that the conditions of atmospheric distillation in Example 2 (purification of crude isopropyl alcohol) were changed to conditions in which the number of plates was 10, the reflux ratio was 1, the temperature of the oil bath was 120° C., the temperature of the tower top was 82° C. and the temperature of the cooler was 25° C., a high-purity isopropyl alcohol in which the concentration of isopropyl alcohol excepting water was equal to or greater than 99.999% by mass was manufactured. For the obtained high-purity isopropyl alcohol, the concentrations of the acetal compound, the aldehyde compound and the ketone compound were measured, and the results thereof are shown in tables 3 to 5. For the obtained high-purity isopropyl alcohol, a water content was measured, and the result thereof is also shown in table 3.

(Acceleration Test)

[0140] On the high-purity isopropyl alcohol obtained as described above, in the same manner as in Example 1, acceleration tests under temperature conditions of 80° C. and 120° C. were performed, and the evaluation of the acetal compound was performed. Consequently, the concentration of the acetal compound was 89 ppb (table 6) at 80° C. and was 100 ppb (table 7) at 120° C.

Comparative Example 2

[0141] In the same manner as in Example 2 except that reduced-pressure distillation in Example 2 (purification of crude isopropyl alcohol) was changed to atmospheric distillation under conditions in which the reflux ratio was 3, the temperature of the oil bath was 120° C., the temperature of the tower top was 82° C. and the temperature of the cooler was 25° C., a high-purity isopropyl alcohol in which the concentration of isopropyl alcohol excepting water was equal to or greater than 99.999, by mass was manufactured. For the obtained high-purity isopropyl alcohol, the concentrations of the acetal compound, the aldehyde compound and the ketone compound were measured, and the results thereof are shown in tables 3 to 5. For the obtained high-purity isopropyl alcohol, a water content was measured, and the result thereof is also shown in table 3.

(Acceleration Test)

[0142] On the high-purity isopropyl alcohol obtained as described above, in the same manner as in Example 1, acceleration tests under temperature conditions of 80° C. and 120° C. were performed, and the evaluation of the acetal compound was performed. Consequently, the concentration of the acetal compound was 270 ppb (table 6) at 80° C. and was 900 ppb (table 7) at 120° C.

Comparative Example 3

[0143] In the same manner as in Example 2 except that atmospheric distillation in Example 2 (purification of crude isopropyl alcohol) was changed to reduced-pressure distillation under conditions in which the pressure was 20 kPa, the number of plates was 10, the reflux ratio was 3, the temperature of the oil bath was 70° C., the temperature of the tower top was 35 to 45° C. and the temperature of the cooler was −5 to 0° C., a high-purity isopropyl alcohol in which the concentration of isopropyl alcohol excepting water was equal to or greater than 99.999, by mass was manufactured. For the obtained high-purity isopropyl alcohol, the concentrations of the acetal compound, the aldehyde compound and the ketone compound were measured, and the results thereof are shown in tables 3 to 5. For the obtained high-purity isopropyl alcohol, a water content was measured, and the result thereof is also shown in table 3.

(Acceleration Test)

[0144] On the high-purity isopropyl alcohol obtained as described above, in the same manner as in Example 1, acceleration tests under temperature conditions of 80° C. and 120° C. were performed, and the evaluation of the acetal compound was performed. Consequently, the concentration of the acetal compound was 200 ppb (table 6) at 80° C. and was 190 ppb (table 7) at 1?0° C.

TABLE-US-00003 TABLE 3 Concentrations in high-purity isopropyl alcohol C7-C12 acetal compound (ppb) Acetal Water C8 C9 Other compound content acetal acetal acetals total (ppm) Example 2 2 3 1 or less 6 or less 10 Example 3 2 3 1 or less 6 or less 10 Example 4 2 3 1 or less 6 or less 10 Example 5 2 3 1 or less 6 or less 5 Example 6 70 20 1 91 10 Comparative 5 10 1 or less 16 or less 5 Example 2 Comparative 100 100 10  210  10 Example 3

TABLE-US-00004 TABLE 4 Concentrations in high-purity isopropyl alcohol C1-C6 aldehyde compound (ppb) Aldehyde Acetal- Propion- Butyr- compound dehyde aldehyde aldehyde total Example 2 400 500 200 1100 Example 3 100 80 100 280 Example 4 50 40 30 120 Example 5 30 20 10 60 Example 6 50 40 30 120 Comparative 800 1200 300 2300 Example 2 Comparative 50 40 30 120 Example 3

TABLE-US-00005 TABLE 5 Concentrations in high-purity isopropyl alcohol C3-C6 ketone compound (ppb) Ketone 3-Methyl-2- compound Acetone 2-Pentanone pentanone total Example 2 500 500 10 1010 Example 3 500 200 1 701 Example 4 100 50 1 151 Example 5 100 50 1 151 Example 6 100 50 100 250 Comparative 500 1000 50 1550 Example 2 Comparative 100 50 5 155 Example 3

TABLE-US-00006 TABLE 6 Concentration of C7-C12 acetal compound in high-purity Amount of isopropyl alcohol after increase in acceleration test of 80° C. (ppb) C7-C12 acetal Acetal compound by C8 C9 Other compound acceleration acetal acetal acetals total test Example 2 25 40 25 90 18 times Example 3 10 15 15 40 8 times Example 4 6 10 3 19 4 times Example 5 4 6 1 11 2 times Example 6 55 30 4 89 1.2 times Comparative 100 150 20 270 18 times Example 2 Comparative 95 95 10 200 1 time Example 3

TABLE-US-00007 TABLE 7 Concentration of C7-C12 acetal compound in high-purity Amount of isopropyl alcohol after increase in acceleration test of 120° C. (ppb) C7-C12 acetal Acetal compound by C8 C9 Other compound acceleration acetal acetal acetals total test Example 2 100 200 50 350 70 times Example 3 30 30 25 85 17 times Example 4 10 12 5 27 6 times Example 5 6 8 1 15 3 times Example 6 60 35 5 100 1.3 times Comparative 300 500 100 900 60 times Example 2 Comparative 90 90 10 190 0.9 times Example 3

[0145] The entire disclosure of Japanese Patent Application No. 2018-188017 filed on Oct. 3, 2018 is incorporated in the present specification by reference.