Method of ethoxylation using vapor phase discharge of ethylene oxide

Abstract: The present invention provides a method for alkoxylating organic compounds comprising contacting an organic compound adapted to be alkoxylated with an alkylene oxide in a reaction vessel under conditions effective to alkoxylate the organic compound. The alkylene oxide is maintained in vapor form during transport to said reaction vessel, during discharge into said reaction vessel, and during contacting of the organic compound with the alkylene oxide . The result is an alkoxylated product containing less flocculant.

Description: Field of the Invention The present invention is a method for alkoxylating polyalkylene glycols, by exposing the polyalkylene glycols to alkylene oxide vapor which is not compressed into a liquid phase for purposes of transport or introduction into the reactor. The method results in alkoxylation products containing less, little, or no flock. Background of the Invention A variety of organic materials react under suitable conditions with an adducting material, such as an alkylene oxide--particularly ethylene oxide or propylene oxide--to form alkoxylated organic materials. Typically, the alkylene oxide adducting material is compressed into liquid form for transport to and discharge into the reactor. Unfortunately, even if the alkylene oxide is decompressed into the vapor phase before the alkoxylation reaction begins, the previous compression of the alkylene oxide into the liquid phase tends to increase flock in the alkoxylation product. A method is needed by which to form alkoxylated products containing no, little, or less flock. Summary of the Invention The present invention provides a method of alkoxylating a polyalkylene glycol comprising contacting the polyalkylene glycol with an alkylene oxide in a reaction vessel under conditions effective to alkoxylate the polyalkylene glycol. The alkylene oxide is in vapor form before and during transport to said reaction vessel, during discharge into the reaction vessel, and during contact with the polyalkylene glycol. Detailed Description of the Invention The present invention provides a method for producing an alkoxylation product with no, little, or less flock. According to the present method, the alkylene oxide adducing material is not compressed into liquid form in order to transport and/or to introduce the material into the alkoxylation reactor. The alkylene oxide is both transported and discharged into the reactor in the vapor phase. Without limiting the present invention to any particular theory or mechanism, it is believed that compression of ethylene oxide into the liquid phase produces minute amounts of oligomers or polymers which contribute to the formation of flock in the substrate. The present invention is believed to reduce flock by avoiding the formation of these oligomers or polymers in the alkylene oxide. The alkoxylation reaction, itself, takes place under standard conditions. The reaction takes place at any suitable temperature, preferably from about 10° C. to about 160° C. For practical purposes, most commercial operations will be carried out in the temperature range of from about 50° C. to about 200° C. The method is useful to alkoxylate any suitable alkoxylatable polyalkylene glycol. The invention is effective to alkoxylate, polyalkylene glycols preferably polyethylene glycol or polypropylene glycol with polyethylene glycol being most preferred. The alkoxylation reaction may be catalyzed using any suitable catalyst. Both basic and acidic catalysts may be used. Suitable catalysts include, but are not necessarily limited to: potassium hydroxide; sodium hydroxide; alkylated aluminum fluorides; alkylated aluminum halides; organoaluminum zinc compounds; calcium, strontium and barium acetates and naphthanates; BF 3 or SiF 4 and metal alkyls or metal alkoxides; and, hydrofluoric acids and metal alkoxides. The alkoxylation may be carried out at ambient pressure or at pressures above or below ambient, as long as the alkylene oxide is maintained in the vapor phase. Normally, the pressure is from -9.7x10 4 (-14) to 2.1x10 5 Pa (30 pounds per square inch (psi)). Pressures below about 1.4x10 5 Pa (20 psi) are preferred. Referring to Fig. 1, in order to conduct the reaction, a suitable reactor that can hold vacuum and pressure may be modified to receive gas or vapor into the top of the reactor. The top of the stainless steel receptacle 16 containing liquid and gaseous ethylene oxide is connected with a tube, hose, or pipe 12 to the vent hole 14 on the reactor head 15. The flow of ethylene oxide gas or vapor is controlled by the valves on the tube 12. The tube 12 preferably includes a "tee" with two valves 18 so that the existing vent hole 14 on the reactor head 15 can be used both for charging ethylene oxide vapor into the reactor 10 through the tube 12 and for venting the reactor 10. A more preferred alternative is to use a reactor with a separate vent hole for venting reactor pressure. Ethylene oxide vapors are allowed to diffuse from the receptacle 16 into the reactor 10 through the tube 12. The separate vent hole is used to release residual inert atmosphere in the reactor once all of the charged ethylene oxide has reacted. Suitable alkylene oxide adducting materials are alpha and beta alkylene oxides, preferably ethylene oxide, propylene oxide or mixtures thereof, most preferably ethylene oxide. The alkoxylated product may have any desired content of the alkoxy adducting material. Where an alcohol is ethoxylated, ethylene oxide will normally comprise from 20 to 90 wt% of the alkoxylated product. A suitable amount of catalyst for use in the reaction is from 0.05 to 10.0 weight percent catalyst based upon the weight of the total reaction mixture. Preferred levels of catalyst are from 0.1 to 6.0 wt% based on the total reaction mixture weight. The invention will be better understood with reference to the following examples, which are provided to illustrate the invention, but not to limit the invention. EXAMPLE 1 After observing undesirable flock in batches of ethoxylated heavy ethylene glycol (EHEG), a series of experiments was performed to determine the cause for flocculation. No correlation could be observed between the percentage of flock and: the percentage of catalyst (in this case, KOH); the reaction temperature (100-160°C); the oxide addition rate; or the hydroxyl number. EXAMPLE 2 Experiments were undertaken to determine whether ethoxylation using only ethylene oxide vapors would prevent flock formation. In the following reaction, ethylene oxide vapor was allowed to diffuse through a tube into a Parr reactor and into contact with the substrate--flash heavy ethylene glycol (FHEG, a stream of PEG produced by Oxychem from which light ends were stripped out). The following reactions were performed: Rxn. # FHEG (g) KOH EO added Total EO Total Product Sample (g) % H 2 O Base # Th Base # (°F 2 ) °C hr. 1319-147 (liq. EO) 957.03 957.03 a. 110.12 .03 (230) 110 846.91 5(aq) 851.91 160 (320) 846.91 1.528 848.4- b. 64.39 0.11 2.08 2.65 (320) 160 0.7 782.64 1.41 250 250 1034 c. 204.1 2.01 (320) 160 0.4 628.2 1.13 200.7 829.95 d. 800.01 1319-149 (liq. EO) 1029.2 1029.2 1029.2 0.6 1029.8 0.26 2 1029.2 0.183 1029.4 a. 116.9 0.26 2 (320) 160 0.08 912.32 0.163 20 932.48 0.25 7 (32) 160 0.75 1319-151 (EO gas or vap.) 1028.1 (82) 28 1028.1 3 1031.1 1.31 1028.1 0.917 1029 a. 33.93 0.10 2 0.969 1.31 2 (223) 106 2.75 994.2 0.887 995.1 b. 62.91 0.06 0.98 5 1.31 2 (225) 107 1.08 931.35 0.831 20 20 952.18 1.28 130 (267) 1.08 931.35 0.831 90 110 1042.2 1.17 132 (270) 6.8 931.35 0.831 185 295 1227.2 c. 12.0 0.99 7 (270) 132 8? The last listed sample 1319-151 exhibited an OH# of 435.6. The samples from reaction 1319-151 remained clear without any trace of flock throughout an observation period of several months. Both 1319-147 and 1319-149 were synthesized with liquid ethylene oxide, and both developed flock. EXAMPLE 3 To demonstrate that using liquid ethylene oxide for ethoxylation would promote flock formation, a clear sample of PEG 200 (from a commercial vendor, similar to FHEG) was ethoxylated with liquid ethylene oxide under the following conditions: PEG 200 (g) KOH EO added Total EO Total Product Sample (g) % H 2 O OH# Base # Th Base # (°F 2 ) °C hr 848.3 2.5 0.764 A. 30.13 0.026 574.4 1.12 1.33 110 (230) 23 818.2 0.74 200 200 1018.9 B. 172.1 439.9 0.74 1.07 110 (230) 1 680 0.61 166.22 846.9 C. 96.73 (230) 110 602.3 0.54 147.23 750.1 D. 713 All samples developed flock within 24 hours. EXAMPLE 4 In order to confirm the results in Example 2, another reaction was conducted. The ethylene oxide vapors were added through the dip tube (20 in Fig. 1). The reaction is summarized below: Rxn.# FHEG KOH Total EO Total Sample % H 2 O Base # (°F) °C hr. Appe arance. 1319-159 (EO vap.) 1001.9 2.92 (aq) 1001.9 0.89 1002.8 a. 39.95 0.3 1.87 110 (230) 1.1 clear 961.99 0.857 962.8 b. 31.8 0.07 0.87 110 (230) 1.25 clear 930.2 0.829 286 1217 c. 55.04 0.78 127 (260) clear 887.53 0.791 272.9 1161.2 d. 1121.5 clear The OH# of the sample with 930.2 FHEG was 448.7. Samples and products from all previous reactions in which ethylene oxide liquid was charged to the reactor developed flock in less than 24-48 hours. In contrast, all of the samples from reaction 1319-159 were sparkling clear with no flock after 5 days at ambient temperature, and remained clear throughout an observation period of several months. EXAMPLE 5 Seven more ethoxylations were conducted in Parr reactors using ethylene oxide in the vapor phase. The conditions and results are given in the following Table: FHEG KOH EO add. Total EO Total Sample % H 2 O B A S # E OH# (°F) °C hr. Appearance Reaction 1319-163 (EO vapors to vapor space with about (30") 1x10 5 Pa of vacuum initially) 995.1 2.95 995.1 0.902 996 A. 58.78 0.09 0.9 (230) 110 clear 936.4 0.85 937.22 B. 41.25 0.05 0.9 (230) 110 0.5 clear 895.2 0.81 260 260 1156 C. 74.67 (260) 127 2.5 sl. hazy 837.34 0.76 243.2 1081.3 D. 1034.8 sl. hazy Reaction 1319-165 (EO vapor to vapor space with about (30") 1x10 5 Pa of vacuum initially) 990.4 2.85 990.4 0.87 991.27 A. 39.9 110 (230) 1.75 clear 950.5 0.84 951.4 B. 35.12 clear 915.5 0.805 275 275 1191.3 C. 55.93 (266) 130 2.7 clear 872.5 0.767 262.09 1135.3 D. 1109 0.63 443.8 clear 1319-167 (EO vapor to vapor phase with about (30") 1x10 5 Pa of vacuum initially) 995.8 2.95 995.8 0.902 996.7 A. 25.56 0.05 0.8 (230) 110 1.25 clear 970.26 0.878 971.14 B. 32.3 0.02 0.81 110 (230) clear 937.99 0.849 291 291 1229.8 C. 52.51 (230) 110 3.38 sl. hazy 897.9 0.81 278.6 1177.3 D. 1107 0.65 437.1 sl. hazy FHEG KOH EO add. Total EO Total Sample % H 2 O B A S # E OH# (°F) °C hr. Appearance 1319-169 (EO vapor through dip tube with about (30") 1x10 5 Pa of vacuum initially-the EO cylinder was very full) 940.3 2.87 940.3 0.877 A. 32.33 0.1 (230) 110 1 clear 907.98 0.847 908.8 B. 32.56 0.05 0.89 (230) 110 1 clear 875.45 0.817 115 115 991.3 C. 64.46 0.79 522.1 (230) 110 1 clear 818.08 0.763 125 232.5 1051.3 D. 64.3 0.75 456.1 110 (230) 0.75 clear 768.04 0.717 218.3 987.01 E. 233.5 clear 586.35 0.547 50 216.61 803.5 F. 740.3 clear Reaction 1319-171 (EO vapors via diptube with about (30") 1x10 5 Pa of vacuum initially) 783.3 2.4 785.7 0.73 784.03 a. 44 0.12 0.9 110 (230) 1.1 b. 63.2 0.06 0.9 (230) 110 0.4 purge and vac. 300 676.2 0.63 200 200 876.8 c. 107.4 (230) 110 2.25 ? 593.4 0.556 175.5 769.4 d. 727.4 451.5 sl. flock 1319-173 (EO vapors through diptube with about (30") 1x10 5 Pa of vacuum initially) 805.1 2.5 807.6 805.1 0.76 803.86 a. 27.7 0.15 1 110 (230) 1 b. 16.2 0.07 0.95 (230) 110 1.25 N 2 purge vac. 300 761.24 0.722 228 228 989.96 c. 110 (230) 110 1.25 EO in continuously 676.7 0.64 202.7 202.7 879.96 d. 830.1 clear FHEG KOH EO add. Total EO Total Sample % H 2 O B A S # E OH# (°F) °C hr. Appearance 1319-175 (EO vapors to vapor space with vacuum) 767.9 2.38 770.3 767.9 0.73 768.6 a. 6.83 16.83 0.18 0.9 6 (230) 110 1 751.1 0.71 751.8 b. 18.1 0.08 0.9 6 (230) 110 1 N 2 purge vac. 300 732.99 0.694 220 220 953.7 c. 106.2 EO in intermittently 651.37 0.617 195.5 847.49 d. clear The samples from 1319-163, -165, -167, -169, -173, and -175 largely remained clear throughout an observation period of several months. A number of the samples developed a slight flock later and appeared slightly hazy. The amounts of flock in these samples were less than those present in samples synthesized with liquid EO. Also, the flock was finer and was more evenly distributed. It was believed that if the EO vapor is pulled from the EO container too fast, rapid effervescence or flash boiling of EO liquid would cause fine liquid droplets of EO to be carried into the reactor, thereby incorporating liquid EO in the reactions. EXAMPLE 6 An experiment (1319-177) was performed using an atomizer to discharge EP vapors into the Parr reactor. The atomizer was installed onto the diptube of one of the Parr reactors in which the length of the dip tube was shortened by cutting off about 0.05 m (two inches). In another experiment using a different reactor (1319-179), EO vapors were charged into the reactor vapor phase with an initial vacuum pressure of about 1.7x10 4 Pa (5" mercury). The conditions and results are summarized in the following Table: FHEG KOH EO added Total EO Total Sample % H 2 O Base # OH# (°F) °C hr. Appearance Reaction 1319-177 (EO vapor through diptube and atomizer, (30") 1x10 5 Pa var.) 1334 4.13 1338.1 1334 1.26 1335.3 a. 32.33 0.4 0.92 (230) 110 2.1 Drying without nitrogen sparge 1301.7 1.23 1302.9 b. 76.3 0.1 0.95 110 (230) 1.3 1225.5 1.16 255 1481.6 (230) 110 3.611 1225.1 1.16 100 355 1581.6 110 (230) 1.6 1225.1 1.16 355 1581.6 c. 1540.1 453.3 clear (4 days) Reaction 1319-179 (EO vapors to vapor phase (w/5") w/1x10 5 Pa vacuum pressure initially) 831.7 2.43 834.13 831.7 0.743 832.44 a. 44.3 0.11 0.94 110 (230) 1.1 787.4 0.703 788.14 b. 45.3 0.01 0.92 110 (230) 1 742.18 0.663 134 134 874.84 110 (230) 1.2 742.18 0.663 88 220 962.84 110 (230) 1.2 742.18 0.663 220 962.84 c. 926.7 444.7 clear (4 days The products were clear initially and remained clear throughout an observation period of several months. EXAMPLE 7 In reaction 1319-183, liquid EO was added or charged into the reactor containing FHEG via the same atomizer used for reaction 1319-177. The resulting product had flock. EXAMPLE 8 The procedures of Example 2 were repeated. No vacuum was used. The conditions and results are summarized in the following Table: FHEG KOH EO added Total EO Total Sample % H 2 O Base # (°F) °C hr. Appearance Reaction 1319-197 (EO vapor added to vapor space of reactor, no vacuum used) 551.5 1.61 553.11 (220) 104 551.5 0.49 551.99 a. 24.18 0.095 10.6 (215) 102 2.3 527.34 0.47 48 48 575.81 (265) 129 2.1 527.34 0.47 89 137 664.81 (265) 129 6 527.34 0.47 30 167 194.81 (260) 127 2.5 527.34 0.47 167 694.81 b. 38.2 (260) 127 2.5 clear The samples were clear and remained clear throughout an observation period of several months. EXAMPLE 9 A mixture of PEG 200 and KOH flakes was charged into a Parr reactor and dried. The procedures of Example 2 then were repeated. The conditions and results are summarized in the following Table: PEG 200 KOH EO added Total EO Total Sample % H 2 O Base # (°F) °C hr. Appearance Reaction 1318-155 (EO vapor to reactor head space) 803.54 2.34 803.54 0.715 a. 31.2 0.22 110 (230) 1.6 b. 8.7 0.14 110 (230) 2.5 c. 12.3 0.19 110 (230) 1.2 d. 16 0.16 116 (240) 1.6 735.4 0.654 736.06 e. 16.8 0.23 116 (240) 1.6 718.6 0.64 122 122 841.3 f. 238.9 110 (230) 2.5 clear 514.5 0.46 38 125.4 640.6 g. 202.1 110 (230) 1.6 clear 352.2 0.31 32 117.8 470.3 h. 204.4 110 (230) 1.7 clear 199.1 0.18 20 86.6 285.9 i. 283 110 (230) 1.95 clear The samples were clear and remained clear throughout an observation period of several months. EXAMPLE 10 The procedures of Example 9 were repeated using an initial vacuum of 3.4x10 5 Pa (10") inside the reactor. The reaction (1318-157) and results are summarized in the following Table: PEG 200 KOH EO added Total EO Total Sample % H 2 O (°F) °C hr. 835.33 2.43 837.76 835.33 0.743 836.07 a. 14.7 0.06 110 (230) 5.3 820.64 0.73 821.37 820.64 0.73 128 128 949.37 110 (230) 2.2 820.64 0.73 132 260 1081.4 b. 1018.6 110 (230) 4.3 The samples were clear and remained clear throughout an observation period of several months. EXAMPLE 11 Finally, an ethoxylation with EO vapor was conducted in a 227 litre (60-gallon) reactor in the pilot plant. The reaction (1318-159) is summarized below: FHEG KOH (g) EO added Total EO Sample % H 2 O Base # (°F) °C hr. Appearance 248 lb 148 a. (6 oz) 0.2 kg 0.38 104 (220) 5 clear b. (16 oz) 0.5 kg 0.08 5927 104 (220) 7 clear (78 lb) 35 kg (78 lb) 35 kg c. (16 oz) 0.5 kg 4685 clear (13 lb) 6 kg 11kg (91 lb) 152 kg d. (336 lb) 433 clear All samples remained clear for at least one month.

Claims: A method of alkoxylating a polyalkylene glycol comprising contacting the polyalkylene glycol with an alkylene oxide in a reaction vessel under conditions effective to alkoxylate said polyalkylene glycol, wherein said alkylene oxide is in vapor form before and during transport to said reaction vessel, during discharge into said reaction vessel, and during contact with said polyalkylene glycol. The method of claim 1 wherein said polyalkylene glycol is selected from the group consisting of polyethylene glycol and polypropylene glycol. The method of claim 2 wherein said polyalkylene glycol is polyethylene glycol. The method of claim 1, 2 or 3 wherein said alkylene oxide is selected from the group consisting of ethylene oxide and propylene oxide. The method of any one of claims 1 to 4 wherein said alkylene oxide is ethylene oxide.

Inventors: LEUNG PHILIP W, LEUNG, PHILIP W.
Applicants: BAKER HUGHES INC, BAKER HUGHES INCORPORATED
Application year: 2000
Main classification: C07C41
IPC codes: C07C41