WO2014042937A1

WO2014042937A1 - Processes for removing monochloropropanediols and/or glycidol from glycerol

Info

Publication number: WO2014042937A1
Application number: PCT/US2013/058121
Authority: WO
Inventors: Jeremie GROOS; Hans-Folkert GROOS
Original assignee: Archer Daniels Midland Company
Priority date: 2012-09-14
Filing date: 2013-09-05
Publication date: 2014-03-20

Abstract

Processes for removing monochloropropanediols and/or glycidol from glycerol are disclosed. Starting glycerol is subjected to treatment with alkali, heat under vacuum, steam, ion exchange resins, or solids to reduce the level of monochloropropanediol. Glycerol compositions low in monochloropropanediol and glycidol are obtained thereby. These compositions may be suitable for food grade glycerol or for modification into food and chemicals.

Description

TITLE

PROCESSES FOR REMOVING ONOCHLOROPROPANEDIOLS AND/OR

GLYCiDOL FROM GLYCEROL

INVENTORS:

Hans Groos, Jeremie Groos

FIELD OF I VEHTIOfS

[0001] The present invention relates to processes for producing glycerol.

Specifically, the present approach pertains to processes for producing compositions comprising glycerol having low levels of nionochloropropanediol and glycidol contaminants and methods for making the compositions.

BACKGROUND

10002] Glycerol is obtained from fats and oils b soapmaking_: fat splitting for free fatty acid manufacture, and biodiesel manufacture. The glycerol obtained from these processes is usually crude glycerol. Crude glycerol is refined for food use.

Contaminants causing potential health hazards have recently been found In glycerol Monochloropropanediols (MCPD) and glycidol are among the contaminants.

[0003] Glycerol is sold In several categories with a typical purity range of 95- 99%. The major refined grades are: USP (U.S. Pharmacopoeia) , PH. EUR.

(European Pharmacopoeia), Kosher, Vegetable, and Technical. USP glycerol contains not less than 95% glycerin, in the European Union, the European equivalent of USP is PH. EUR. (European Pharmacopoeia). This grade is produced from natural fats or vegetable oil (triglycerides) and generally used in pharmaceuticals, cosmetics and food applications. Kosher grade glycerin meets ail USP requirements and Is produced either naturally from 100% vegetable oil or synthetically in facilities designated as kosher. Vegetable grade glycerol also meets all USP requirements and is produced naturally from 100% vegetable oil. Technical grade glycerol has no Industry standard, although is generally 97-99.5% glycerol.

00043 Crude glycerol often originates from fats or oils and may he obtained from fat splitting, soapmaking, or biodiesel manufacture. Fat splitting is often carried out with alkali, such as sodium hydroxide, or by applying heat and pressure in the presence of water. Crude glycerol from biodiesel manufacture often contains significant amounts of alkali, such as sodium hydroxide, The alkali is often neutralized with acid, especially hydrochloric acid, which may also lead to formation of MCPD in the glycerol, if is expected thai the use of alternate acids, such as sulfuric or phosphoric rather than hydrochloric, for neutralization and splitting soaps in glycerol would reduce or eliminate potential sources of chloride/chlorine which may contribute to formation of MCPD and glyeidol. Crude glycerol from biodiesel manufacture Is dried to form dried glycerol (Fig. 1). Dried glycerol is distilled in a distillation column to torn? an overhead phase comprising glycerol and a bottom phase comprising a mixture of salt and glycerol. Overhead glycerol is sent to a deodorizer, where it is contacted with steam under vacuum to remove impurities which are more volatile than the glycerol, and passed through activated carbon to produce refined glycerol of greater than 99.5% purity. The bottom salt and glycerol phase from the distillation column is processed in a thin film evaporator. The overhead from the thin film evaporator comprising glycerol vapor is condensed and/or washed in a

condenser/washer and the condensed glycerol is sent to the deodorizer.

[000SJ An alternative source of MCPD and giyeldo! in glycerol is from oils which have undergone physical refining, such as palm oil. Glycerol obtained from physically refined oils often contains more MCPD than glycerol from chemically refined oils,

[0008] When crude glycerol is processed, monochloropropanediols (3- monochloropropanediol and 2-monochioropropanedioi) &η 'οτ glyeidol may be produced. According to EU Commission Regulation No, 231/2012 (March 9, 2012) regulations laying down a limit of 100 ppb 3-MCPD in food additive glycerol entered Into force December 1 _: 2012.

{0007J Due to improvements in analytical methodology and increases In understanding of toxicology, government regulation and intervention are expected to continue to impose tighter limits on the levels of monochloropropanediols and glyeidol in food ingredients and foodstuffs. The removal of glyeidol esters and MCPD from vegetable oils has been demonstrated. However, the removal of polar compounds like glyeidol and MCPD from a polar matrix such as glycerol is a different and more difficult problem than removing the glyeidol esters and MCPD esters from a non-polar matrix, such as vegetable oil. There is a significant commercial demand for glycerol compositions having a low level of monochloropropanediols and glyeidol. In spite of this no methods for reducing these contaminants in glycerol have been available. SUMMARY OF THE INVENTION

[0008] New processes for removing monoc. loropropanediols, glycidol, or a combination thereof from glycerol are disclosed. In an aspect, glycerol Is contacted with a member selected from the group consisting of alkali, heat under vacuum, steam, an ion exchange resin, a solid, and combinations of any thereof, thus producing a purified glycerol.

[0009] In an aspect, a solution comprising contacting glycerol having an initial level of a monoch!oropropanediols or glycidol with at least one of alkali, heat under vacuum, steam, a solid, or an ion exchange rosin to obtain glycerol has been created, wherein the content of at least one monochioropropanedlol or glycidol in the glycerol Is reduced after contacting.

0010] In an aspect, glycerol can be produced with low levels MCPD and giycldol. In an additional aspect, a product produced by the processes of the present invention is disclosed.

BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 shows a process block diagram for producing refined glycerol from crude glycerol obtained from biodiesel manufacture Crude glycerol from biodiesel manufacture is dried to form dried glycerol. Dried glycerol is distilled in a distillation column to form an overhead phase comprising glycerol and a bottom phase comprising a salt glycerol mixture. Overhead glycerol is sent to a deodorizer, where if is contacted with steam to remove contaminants that are more volatile than glycerol, and passed through activated carbon to produce refined glycerol of greater than 99.5% purity. The bottom salt and glycerol phase from the distillation column is processed in a thin film evaporator. The overhead from the thin film evaporator comprising glycerol vapor is condensed and/or washed in a condenser/washer and the condensed glycerol is sent to the deodorizer.

DETAILED DESCRIPTION

[0012] As used herein, "monochloropropanediol" includes 3-mono- chioropropane-1 ,2-diol (3-MGPD) and 2·· rnono-ch!oropropane-1 ,2-dioi (2-MCPO).Vlonochloropropanediol is a contaminant thai occurs in food In its non-esferified (dioh form,

[0013] As used herein, "contacting glycerol with alkali" refers to contacting glycerol with alkali substances that render starting glycerol streams more alkaline, resulting In the decrease in the content of MCPD or glycidol impurities in subsequent process compositions. For example, contacting crude glycerol having a given initial pH and an initial level of MCPD or glycidoi with alkali will result in an increase in pH and a decrease in the content of MCPD or glycidoi in subsequent process streams, such as dried glycerol, overhead phase from a distillation column, a bottom phase mixture of salt and glycerol, overhead from a thin film evaporator, condensed glycerol, or refined glycerol of greater than 99,5% purity.

[0014] As used herein, "contacting glycerol with heat under vacuum" refers to heating a starting glycerol under a vacuum at a defined temperature range, whereby the glycerol is evaporated from the impurities and condensed. The content of at least one monochioropropanedioi or glycidoi in the condensed glycerol is lower than the level of at least one monochioropropanedioi or glycidoi in the starting glycerol. The heating may be carried out under conditions of temperature and pressure such that the glycerol is near the evaporation point, for example under 5-30 mbar vacuum and at 150 -185 °C. The temperature of the evaporation point of glycerol is related to the vacuum applied.

[0015] As used herein, "contacting glycerol with supplemental steam" refers to contacting glycerol with steam in the deodorizing process, where steam is added to glycerol heated under vacuum. The supplemental steam refers to using a greater amount of steam than is normally used in deo ohzation of glycerol. For example, glycerol that is normally deodorized with 0.9% steam may be supplemented with steam to supply 1 % or more steam. The content of at least one

monochioropropanedioi or glycidoi in the deodorized glycerol is lower than the level of at least one monochioropropanedioi or glycidoi In the starting glycerol.

[0016] As used herein, "contacting glycerol with a solid" refers to solids such as silica, cellulose, wood pulp, activated carbon, ion exchange resins, diatomaceous earth, or combinations of any thereof. Suitable solids include silica, such as Trysii™, available from W. R. Grace, Chicago, IL USA; cellulose, such as wood pulp.

Including Filtracell EFC 950 C-plus, available from Filtrcell, Johannesburg, South

Africa; activated carbon, such as Epibon YM 12x40 Donau™, available from Donau

Carbon, Springfield, NJ, USA and CAL12x40 Chemviron™, available from Calgon

Carbon, Feluy, Belgium; and diatomaceous earth, such as LehVoss Celite 209™,

Hamburg, Germany. The content of at least one monochioropropanedioi or glycidoi in the solid-contacted oiycerol is lower than the level of at least one

monochioropropanedioi or glycidoi in the starting glycerol C 01?3 As used herein, "contacting glycerol with ion exchange resins"

Includes contacting with strong base ion exchange resins, weak base ion exchange resins, strong acid ion exchange resins, weak acid Ion exchange resins, nonfunctional resins, mixed bed resins, or combination of any thereof. Exemplary resins include Merck Ion Exchangers, such as type II, type III and type IV, available from Merck, Whitehouse Station, New Jersey; Amberlite™ type III 20, type IRN1 S0, type 1R120, type MB61 13, Amberjet™ 420001, and Amberlyst™ A2 80H, from Rohm & Haas, Philadelphia, Pennsylvania; Puroiite™ type C15GS, type Copolymer, type CI 00, type A100, type A103S, and type A500OH, from Purolite, Ratingen, Germany; le atit™ K2629 from Lanxess, Leverkusen, Germany; Dowex™ DRG8 and Dowex™ 22 from Dow Chemical Company, Midland, Ml USA; Diaion™ PA308, Diaion™ HPA 25, and Diaion™ PA412, from Mitsubishi Chemical Co., Tokyo, Japan; Tuision™ A-30MP, Tuision™ A-36, Tulsion™ A-74MP, Tuision™ A72-MP from Thermax USA, Northviile, Ml, USA; Lewatit™ P607, Lewaiit™ 7488, Lewatit^m VPOC, Lewatit^rMS4268, and Lewatit™ MP300, from Lanxess, Chardon Ohio, USA;. The content of at least one monochloropropanediol in the glycerol contacted with ion exchange resin is lower than the level of at least one monochloropropanediol or glycidoi in the starting glycerol.

[0018J Monoehloropropanediols are measured by the DGF Standard Method C-IV 18 (10) at Institut Kirchhoff Berlin GmbH, Berlin, Germany. An alteration st that method using sodium bromide is used to determine glycidoi levels. The defection limits of the method are 50 ppb (parts per billion) for 3- CPO, 2-MCPD, and glycidoi. Alternatively, 3-MCPD can be measured according to "Determination of residual free epoxide in polyefher polyols by derealization with iethyiammonium H,M~

dietbyldithiocarbamafe and liquid chromatography 'Journai of Chromatography A, vol. 898 (1995) 41-47, with a limit of detection of 10 ppb. Giycidof can also be quantified according to the BfR Method 9 fv CPD-FA-Esfers ^aMethod-82-FC-009-02" updated 15.02,2010, with a limit of detection of 10 ppb.

[0019] One non-limiting aspect of the present disclosure is directed to a process for removing monochloropropaneciiois, glycidoi, or a combination thereof from glycerol, the process comprising contacting glycerol with a member selected from the group consisting of alkali, heat under vacuum, steam, an Ion exchange resin, a solid, and combinations of any thereof, thus producing a purified glycerol. 00201 O e non -limiting aspect of the present disclosure is directed to a glycerol composition in which the level of MCPD or glyeidoi in the composition is less than 1000 part per billion, less than 500 parts per billion, less than 100 parts per billion, less than 50 parts per billion, or less than 10 parts per billion.

[0021] In another no -limiting aspect of the present disclosure, glycerol may be obtained from fat splitting, soapmaking, or biodiesel manufacture.

[0022] Another non-limiting aspect of the present disclosure is directed to reducing the level of at least one of 3-MCPD, 2-lvlCPD or glyddol in crude glycerol by contacting the crude glycerol with alkali to raise the pH of the glycerol: the glycerol may then be dried, !n a non-limiting aspect of the disclosure, the pH of the glycerol may be raised to at least a pH of 9.

[0023] Another non-limiting aspect of the present disclosure is directed to reducing the level of at least one of 3-MCPD, 2- CPD or glycldol In glycerol by contacting the glycerol with heat under vacuum. In another non-limiting aspect of the present disclosure the hearing under vacuum is carried out under conditions of temperature and pressure such that the glycerol is below an evaporation point of the glycerol.

[0024] Another non-limiting aspect of the present disclosure is directed to reducing the level of at least one of 3-MCPD, 2-MCPD or glycldol in glycerol by contacting the glycerol with heat and steam under vacuum in the presence of steam at a level of greater than 0.9 weight percent steam based on the weight of glycerol, in a non-limiting aspect, the heating under vacuum in the presence of steam takes place in a deodorizer.

[00251 Another non-limiting aspect of the present disclosure is directed to reducing the level of at least one of 3-ivlCPD, 2-MCPD or glycldol in glycerol by contacting the glycerol with beat under vacuum, wherein the glycerol is evaporated, in another non- limiting aspect of the present disclosure, the evaporated glycerol is condensed and at least one of monochloropropanediois and glycldol are carried away in the vapor phase,

[0026] Another non-limiting aspect of the present disclosure is directed to reducing the level of at least one of 3-MCPD. 2-MCPD or giycidoi in glycerol by- contacting the glycerol with a solid selected from the group consisting of silica, cellulose, wood pulp, activated oarbon, Ion exchange resins, diatomaceous earth, and combinations of any thereof.

8 [0027] Another non-limiting aspect of the present disclosure is directed to reducing the level of at least one of 3-MCPD, 2-IV!CPD or giycidoi in glycerol by contacting the glycerol with an ion exchange resin selected from the group consisting of strong base ion exchange resins, weak base ion exchange resins, strong acid ion exchange resins, weak acid ion exchange resins, mixed bed resins, nonfunctional resins, and combinations of any thereof. In another non-limiting aspect of the present disclosure, glycerol is contacted with a base ion exchange resin and with an acid ion exchange resin. In another non-limiting aspect of the present disclosure, the glycerol that is contacted with a base Ion exchange resin and an acid ion exchange resin is contacted with the base ion exchange resin first, followed by contacting with the acid ion exchange resin. In another non-limiting aspect of the present disclosure, the glycerol that is contacted with an ion exchange resin is contacted with carbon.

[0028] Another non-limiting aspect of the present disclosure Is directed to glycerol obtained by the methods outlined herein, Another non-limiting aspect of the present disclosure Is directed to glycerol wherein the content of a

monochloropropanedsol, the giycidoi, or a combination of any thereof is less in the purified glycerol than in the glycerol which has not been contacted, in a further embodiment, products obtained by the methods outlined herein ma be used, for example in food and beverages, personal care products, oral care products, tobacco, pharmaceuticals, polyether polyols, propylene glycol, recreational vehicle fluids, per foods, aikyd resins, deicers, completion and fracture fluids, drilling muds,

polyglycerols, concrete and asphalt lubrication, and eplchlorohydrin production.

EXAMPLES

[0023] The following examples illustrate methods for removing

monochloropropanedlols and/or giycidoi from glycerol, and compositions of glycerol containing low levels of monochloropropanediols and giycidoi, according to the present invention. The following examples are illustrative only and are not intended to limit the scope of the Invention as defined by the appended claims.

EXAMPLE 1

|0030] Adjustment of pH of glycerol A sample of crude glycerol from blodiesel having a pH value of 7 was obtained (ADM, Hamburg, Germany), The glycerol was subjected to glycerol drying to obtain glycerol dryer bottoms. The glycerol dryer bottoms were analyzed by DGF Standard Method C-IV 18 (10) at Institut Kirchhoff Berlin GmbH, Berlin, Germany (Table 1 ). [00311 A second aitquoi of the crude glycerol was treated to adjust the pH to a pH value of 12 before being subjected to glycerol drying to obtain glycerol dryer bottoms (from alkali treated glycerol, pH 12). The levels of MCPD were determined (Table 1 ).

Table 1 . Glycerol dryer bottoms from glycerol dryer producing dried glycerol from crude glycerol. Glycidol content was calculated.

1 j MCPD (ppb) i Glycidol (ppb) 1

1 Glyc erol bottoms from pH ? glycerol I 5990 ! 150 j

1 Glyc eroi bottoms from pH 12 givcerol i 2040 i «50 i

[0032] Glycerol dryer bottoms having an MCPD content of less than 5 ppm were obtained when the pH of the glycerol before glycerol drying and glycerol distillation was adjusted to 12, indicating the ability of contacting the glycerol with alkali to remove MCPD and glycidol.

EXAMPLE 2

[D033J H§ os.^| c rg[ .under vacuum A sample of contaminated overhead glycerol containing 2080pph 3-MCPD, 8000 ppb 2-MCPD, and 65 ppb glycidol was subjected to heating for one hour to 185 ^:'C (just under the evaporation point of glycerol) under 15 mbar vacuum. Significant reduction in MCPD and glycidol was obtained by heating the glycerol to just under the evaporation point of the glycerol (Table 2), indicating the ability of heating the glycerol to just nde the evaporation point of the glycerol to remove MCPD and glycidol.

P>034J Increasing strip steam in deodorizing glycerol Contaminated overhead glycerol (containing 2060ppb 3-MCPD, 8000 ppb 2-MCPD, and 65 ppb glycidol) was subjected to heat and steam under vacuum to carry out glycerol deodorization as normal, with 19 kg/hour (1 .2 weight percent steam based on the weight of glycerol) stripping steam (1 1 bar). Deodorized glycerol containing 310 ppb 3-MCPD, 1 1 10 ppb 2-MCPD and <50 ppb glycidol was obtained. When the same contaminated overhead glycerol was deodorized with supplemental stripping steam (30 kg/hour), contaminant levels In the deodorized glycerol were reduced further to 1 10 ppb 3- MCPD, 610 ppb 2-MCPD and 50 ppb glycidol (Table 2) indicating the ability of deodorizing the glycerol with supplemental steam to remove MCPD and glycidol.

[Q03§3 Evaporation of glycerol Contaminated overhead glycerol was distilled at various temperatures under vacuum, MCPD and glycidol were carried away in the vapor phase, Glycerol was condensed to yield refined glycerol having a monochloropropanediol content of less than five pads per million (Table 2).

[0036| After heating under vacuum, deodorizing with supplemented steam, and condensing evaporated glycerol, glycerol compositions having reduced levels of monochloropropanediois and glycidol were obtained, indicating the ability of evaporating and condensing glycerol to remove MCPD and glycidol.

EXAMPLE 3

[0037] Contactin|LgiY∞ Contaminated refined glycerol containing 470 pph 3-MCPD, 3200 ppb 2-MCPD, and <50 ppb glycidol (ADM.

Hamburg, Germany) was contacted with solids. Solids (5 wt %} were added to contaminated glycerol and stirred for 4 hours at 80 °C, and the resulting solid- contacted glycerol was analyzed.

Activated Carbon

CAL12X40 Chemviron™

Activated Carbon 420 3170 <50

LehVoss Ceiite 209 400 1210 <50

[0038] Slight reduction In the MCPD content of glycerol took place after treatment with activated carbon or Trysii™ silica. After treatment with wood pulp or diatomaceous earth (ceiite), significant reduction in the MCPD content of glycerol was obtained, indicating the ability of contacting glycerol with a solid to remove MCPD, EXAMPLE 4

{00393 Contacting glycerol with an ion exchange resin Contaminated refined glycerol from Example 3 was contacted with ion exchange resins (5 vol. percent of the glycerol) for 2 hours at 80 °C with agitation at 150 RPM substantially as outlined in Example 3. (Table 4A).

Table 4A. Levels of 3-MCPD and 2 -MCPD in contaminated refined glycerol after contacting with ion exchange resins. Giycidol content was calculated.

3-MCPD (ppb) 2- CPD (ppb) Giycidol (ppb)

Contaminated glycerol 470 3500 <50

Merck Ion Exchanger 11™ 450 2020 <50

Merck ion Exchanger 111™ 190 320 125

Amberlite™ ΠΊ20 430 3320 <50

Amberiite™ 1RN150 <50 280 120

Amberiite™ IR 120 430 3240 <50

Amberiite™ B61 13 <50 420 80

Merck Ion Exchanger IV™ 420 3120 <50

Purolite™ C150S 420 3150 <50

Puroiite™ Copoivrner ^'430 3160 <50

Puroiite™ C1G0 440 3250 <50

Lewatit™ K2629 ^'480 1300 <50

Dowex™ DRG8 480 1360 <50

Diaion™ PA308 460 V27Q <50

Adako™ ACC142200 plus 440 Ϊ240 <50

Purofite™ A100 470 3200 <50

Puroiife™ A103S 336 2450 <50

Puroliie™ A500 OH <50 <50 274

0040J Significant reduction in MCPD was obtained with several ion exchange resins. When contaminated glycerol containing 470 ppb 3-MCPD and

3500 ppb 2-MCPD was treated with Puroiite™ A500 OH, the levels on 3-MCPD and 2-MCPD were both reduced to below the detection limits of the DGF Standard Method C-1V 18 (10) at Institut Kirchhoff Berlin GmbH, Berlin _: Germany, indicating the ability of contacting glycerol with a Ion exchange resin to remove MCPD. [0041] A 3 Normal solution of crude glycerol was spiked with 3-MCPD to contain the 3-MCPO levels indicated in Table 4B and contacted with conditioned ion exchange resins. Resins were conditioned to hydroxide form in a column by passing

5 bed volumes of 5% sodium hydroxide solution through the resin at 5 bed volumes/hour, The resins were rimed with 10 bed volumes of water, then removed from the column and interparticie water was removed on a Buchner funnel. Glycerol

(100 mt) was added to a 250 mi shake flask and 10 ml of conditioned resin was added. The resin and glycerol were shaken together for 4 hours at 80 ^C'C. then the resin was removed by filtration (Table 48).

Table 4B. Levels of 3-MCPD contaminated refined glycerol after contacting with ion exchange resins. 3-MCPD was determined according to BfR Method 9 MCPD-FA-

[8042] Some resins were able to reduce the levels of 3-MCPD by more than

100-foki indicating the ability of contacting glycerol with ion exchange resin to remove MCPD.

[0043] Selected resins from Table 4B were contacted with glycerol spik with 3-MCPD to contain 1694 ppb 3-MCPO for three hours (Table 4C). Table 4C. Levels of 3-MCPD contaminated refined glycerol after contacting with ion exchange resins. 3-MCPD was determined according to BfR Method 9 fv!CPD- FA -

3-MCPD (ppb, 1.5 hours) 3-MCPD (ppb, 3 hours)

Contaminated glycerol 1854 1654

Puroiite™ A500 133 10

Dowex™ 22 1258 <ϊο

Mitsubishi Diaion™ PA412 515 <io

Mitsubishi Dsaion™ PA308 344 <10

Mitsubishi Oiaion™ HPA 25 86 < 10

[00441 Each resin was able to remove 3-MCPD to below detection limits in three hours, indicating the ability of contacting glycerol with ion exchange resin to remove CPD.

EXAMPLE 5

[004S] Effects of heating on removal of MCPD with ion exchange resin A sample of contaminated overhead glycerol containing 2080 ppb 3-MCPD, 8000 ppb 2-MCPD, and 65 ppb glycidol was obtained from the first glycerol distillation column (ADM, Hamburg, Germany). Aliquots (200 grams) were contacted for 2 hours with 5 vvt % Puroiiie™ ASGG strong base ion exchange resin in the hydroxy! form

substantially as outlined in Example 3 except, that the temperature of contact was varied (Tabie 5).

Table 5. MCPD and glycidol content of glycerol after treatment with strong base resin

3-MCPD (ppb 2-MCPD (ppb) Glycidol (ppb)

Contaminated glycerol 2060 3000 85

2.0 X 1950 8150 220

40 1320 5250 435

60 X 470 3850 783

^•SO X <50 560 555

[00461 When glycerol was contacted with A5G0 solid base ion exchange ressn for 2 hours, increasing the temperature above 20 X caused a greater reduction in MCPD. Treatment at 80 ^!>C resulted in a 94% reduction in MCPD, Indicating the ability of contacting glycerol with ion exchange resin at a temperature greater than 20 X to remove MCPD.

EXAMPLE 6

[0047] Contacting .glycerol with varying amounts of ion exchange resin

Contaminated glycerol from Example 4 was contacted with varying amounts of ion exchange resins for one or two hours at 60 substantially as outlined in Example 3 (Table 8). Amberli e™ IRN150 comprises a mixture of cation and anion exchange resins.

Table 8. MCPD and glycidol content of glycerol after treatment with strong base resin at various amounts (voiume % resin). Glycidol content was calculated.

[00481 Incubation with 10% Purolite™ A500 strong base resin caused a reduction in MCPD of 38% after one hour and 94% after two hours. Incubation with Amherilte™ MB6113, Merck ion exchanger HI™, and Amberjiie™ IRN15G (mixed bed) for two hours caused a reduction in UOPD of 70, 90, and 75%, respectively, indicating the ability of contacting glycerol with ion exchange resin to remove MCPD. EXAMPLE 7

[0049J CogLfin ^ an ion exchange resin in a column

Puroiite™ A500 strong base resin was packed into a column (1 cm diameter, ~8 cm height) and contaminated refined glycerol containing 860 ppb 3- CPD, 4590 ppb 2- CPD, and <50 ppb glycidol was contacted with the ion exchange resin at 25

ml/hour and at 24-70 °C in a first cycle to yield a glycerol composition having reduced levels of monochloropropanediois. When the 2-MCPD content of the treated glycerol effluent reached 370 ppb_; the base ion exchange resin was regenerated by treating with a 4%:- solution of sodium hydroxide and a second cycle of contacting with the same feed was carried out. The regeneration cycle after loss of activity was repeated three times without significant loss of performance (Table 7).

Table 7,

I Cycle 3, after 356 bed volumes j <50 1 190 1 310

[0060] The resin was able to remove 3- CPD throughout but slowly lost the ability to remove 2- CPD. Regeneration of the ion exchange resin restored the ability of the resin to remove V!CPD.

5 [0051] Contj^

Three jacketed columns (15 mm inner diameter) were packed with 100 ml strong base ion exchange resin. The first coiumn was packed with Purolite™ A500OH resin; the second was packed with Mitsubishi Diaion™ PA412 resin; the third coiumn was packed with Dowex™ 22 resin. Resins were conditioned by passing 5 bed volumes i o (BV) of a 5% solution of sodium hydroxide at 8,3 ml/minutes, then 10 BV of

deionized wafer. The coiumn temperatures were set to 60 °C. A starting glycerol comprising U.S. P. glycerol containing 2103 ppb 3 -MCPD and 99% glycerol was contacted with the ion exchange resin by heating to 90 °C before passing it from the top through the resin beds at 07 mL rninufe. The 3-MCPD levels were quantified

I 5 according to "Determination of residual free epoxide i polyeiher polyo!s by

d ealization with diethyiammonium Ν,Ν-dielhyldithiocarbamate and liquid

chromatography,^'' Journal of Chromatography A, vol. 698 (1995) 41 -47, The limit of defection was 10 ppb. Glycidol was quantified according to the BfR Method 9 CPD- ΓΑ-Esters ^MMeihod-82-FC-009-02^s updated 15.02.2010; the limit, of detection was 10 0 ppb.

[00S2] Four bed volumes of glycerol were passed through each of the columns and the levels of MCPD and glycidol were measured (Table 8).

Table 8. Reduction of 3-MCPD and glycidol after contacting with base ion exchange 5 resins at 80 ^*C.

Dowex^'™ 22. after 4.0 bed volumes

[00S3J The column packed with Mitsubishi Diaion™ PA412 resin was tested for 19 bed volumes. Glycerol containing 1493 ppb 3-MCPD and 992 ppb glycidol was passed through the resin at 0.7 ml/minute. The level of MCPD was quantified after 7, 13, and 1 bed volumes; in each case, the level of 3-MCPD In the column effluent was <10 ppb, , indicating the ability of contacting glycerol with ion exchange resin to remove MCPD.

[00S4] The columns containing Puroiite™ A600OH ressn and Mitsubishi

Diaion™ PA412 resin were regenerated by passing 5 bed volumes (BV) of a 5% solution of sodium hydroxide at 8.3 rnL/minutes, then 10 BV of deionized water, then tested again with higher flow rates. Two bed volumes of glycerol were passed through the resins at 1.4 ml/minute, 2.8 mliminute, 5.6 ml/minute, and 11.2

ml/rninule. in each case, the level of 3-MCPD in the column effluent after 2 bed volumes was <10 ppb, Indicating the ability of contacting glycerol with regenerated ion exchange resin to remove MCPD.

EXAMPLE 9

acid Ion exchange resin, Contaminated refined glycerol containing 500 ppb 3-MCPD, 2625 ppb 2-1V1CPD, and <50 ppb glycidol was contacted with base ion exchange resin (Puroiite™ A500OH) packed In a column (1 cm diameter, ~6 cm height), then contacted with 20 ml of an acid resin (Puroiite™ CI SOS) packed in a second column (1 cm diameter, 12 cm height), then contacted with active carbon at a flow rate of 25 roL/hour. The temperature was varied between 24^"-^' to 70 X, The levels of impurities in the contacted (purified) glycerol were below detection limits (<50 ppb 3MPCQ, <50 ppb 2- CPD, and <50 ppb glycidol) after 328 bed volumes. After 614 bed volumes the levels of 3-MCPD and glycidol in the contacted (purified) glycerol were below defection limits ( 50 ppb), and the level of 2- MCPD was 200 ppb , indicating the ability of contacting glycerol with ion exchange resins and carbon to remove MCPD.

EXAMPLE 10

Combination of bag and acid ion exchanfle,resiri coJuQij Crude glycerol ;260 ppb 3- MCPD, 1660 ppb 2-MCPD, <50 ppb Glycidol) was passed through a base ion exchange resin followed by an acidic ion exchange resin. The base Ion exchange resin comprised regenerated 10 ml Puroiite™ A5D0 (regenerated as described in Example 7 to 92.9% alkalinity); the acid ion exchange resin

comprised 20 ml Puroiite™ C150SH, Basic ion exchange resin converted CPD to giycidol but imparted an odor to the glycerol stream. Treatment with acid resin reduced the giycidol content of the glycerol stream and removed most of the odor that leached from the base resin. Glycerol was passed at 25 mL/h through the columns (1 cm diameter) held at 70 X. The contact time with the base Ion exchange resin was 0.4 hours, and the contact time with the acid resin was 0.8 hours. The level of 3- CPD in glycerol e!uted from the columns was less than 100 pg kg for the first 368 bed volumes. The level of 3-MCPD in glycerol eiuted from the columns was 134 and 263 mlcrograms/kg through 480 ~ 857 bed volumes, A total of 939 bed volumes were treated In these columns before regeneration. The 10 ml Puroiite™ A500 was regenerated as described in Example 7 to 97.20% of the original alkalinity. Spiked glycerol was prepared by adding 3-MCPD to pure glycerol to obtain spiked glycerol feed containing 655 pg/kg 3- CPD. No 2-MCPD or giycidol were added. The spiked glycerol feed (899 bed volumes) was passed through the basic and acidic resin to yield 17.9 liters of glycerol containing less than 100 miorograms/kg 3-MCPD, , indicating the ability of contacting glycerol with ion exchange resin to remove MCPD. EXAMPLE 11

[00S6] Capacit ..of add Acids were tested as agents for regeneration of acid resins. The capacity of acid resins that had been shown to be effective (Amberlite I N12G & Puroiite CI 50} was exhausted by contacting the acid resin with sodium chloride solution. The acid resin titrated with 0.1 molar hydrochloric acid using phenolphihaiein indicator to confirm thai the acid resin was exhausted (capacity of 0.00 mmol/g resin). This point was determined by withdrawing 1 gram of resin from the column, which was stirred in 50 ml 0.1 molar potassium hydroxide for 60 minutes at room temperature. Exhausted resin loaded into a column (1 cm diameter. 25 cm bed height). Exhausted acid resins were treated with citric acid (0.8 mmol/gram of resin), phosphoric acid (1.08 mmol/gram of resin, or hydrochloric acid ( .51 mmol.gram of resin). The acid resin was removed from the column and two bed volumes of the respective acid solution (20% vol/vol solutions of phosphoric and citric acids, and 5% vol/vol solution of hydrochloric acid) at 70 X was stirred with the resin at 70 X for 30 minutes. The acid resins treated with phosphoric and citric acids were washed with 3 bed volumes of deionized water, and the acid resin treated with hydrochloric acid was washed with 3 bed volumes of deionized water. The wash water was free of chloride. The regenerated acid ion exchange resin was contacted with glycerol eiuted from a base ion exchange resin to generate glycerol having reduced levels of MCPD and glycidol.

EXAMPLE 12

[0SS?1 Plant scaje_.prgc^s Crude glycerol recovered from palm oil hlodiesel was continuously dried in a glycerol dryer, then continuously fed to a glycerol distillation column. The bottoms from the glycerol distillation were

continuously fed to a thin film evaporator. Glycerol vapor from the thin film evaporator was combined with the glycerol vapor from the glycerol distillation column and condensed continuously. The condensed glycerol was deodorized and passed continuously through two columns (each holding 2 cubic meters). The first column contained base ion exchange resin (Puroiite™ A500OH), the second column contained an acid resin (Purolife™ C15GS). The effluent from the second column passed continuously through an active carbon filter to yield 81 1 bed volumes (1539 metric tons) of purified glycerol containing greater than 99,5% pure glycerol and containing less than 100 ppb 3-MCPD.

EXAMPLE 13

[DOSS] Breakthrough tests of SBA resins Jacketed glass columns (100ml,

15mm diameter) were loaded with the desired SBA resins. These resins were then rinsed with deionized water, followed by a conditioning step in which 500 ml (5 bed volumes (8V)) of 5% NaOH was pumped through the resin at a flow rate of l Orni/min. The column was then rinsed with 5BV of deionized water. The column was then connected to a fraction collector. The column temperature was kept constant at

60^CC; glycerol feed spiked with 3-MCPD to contain 1055-1856 ppb 3-MCPD was then applied to the resin column at a rate of 10 ml/min and samples were collected in 500 ml fractions. This test was run until the effluent of any column reached lOOppb 3- MCPD for several samples in a row,

Table 1 1 , Breakthrough tests of SBA resins

BV Treated before Average 3-MCPD

Resin Type

breakthrough Reduction, %

Mitsubishi Dlalon™ PA 412 99,6

Mitsubishi Diaion™ PA 308 179 92.3

Lewaiit™ S6368 109 91 ,6

I S ! Puro!tte™ A500 ! 86 ! 05.9 j

! Lewatit S7468 \ 144 ! 93.8 I j Dowex™ 22 44 I 95.4 j

^*The PA 412 column blinded off after"! 6G BV St was not possible to pump any more feed through.

[O059| Although the PA412 resin showed the highest average 3 v1CPO reduction, the breakihougn was never reached due to blinding off of the resin, In addition, 3--MCPD was undetectable in the column effluent for the first 100 bed volumes. The PA308 resin was able to run the longest before the 3-MCPD content of the effluent was as high as the breakthrough level (100 ppb).

[0060] While the foregoing invention has been described in some detail for purposes of clarity and understanding, it will be appreciated by one skilled in the art from a reading of this disclosure that various changes in form and detail can be made without departing from the true scope of the invention and appended claims.

Claims

CLAIMS What is claimed Is;

1. A process for removing monochloropropanediols, glycidol, or a combination thereof from glycerol, the process comprising:

contacting glycerol with a member selected from the group consisting of alkali, heat under vacuum, steam, an ion exchange resin, a solid, and combinations of any thereof, thus producing a purified glycerol.

2. The process of claim 1 , wherein the monoch!oropropanediol content of the purified glycerol Is less than one thousand parts per billion.

3. The process of claim 1 , wherein the monochloropropanedioi content of the purified glycerol Is less than one hundred parts per billion.

4. The process of claim 1 , wherein the monochloropropanedioi content of the purified glycerol is less than fifty parts per billion.

5. The process of claim 1 , wherein the monochloropropanedioi content of the purified glycerol is less ten pads per billion.

8, The process of claim 1 , wherein the glycerol is obtained from at least one of fat splitting, so-apmaking, and blodiesel manufacture.

7. The process of claim 1 , wherein the glycerol comprises crude glycerol, the process further comprising:

raising the pH of the crude glycerol; and

drying the crude glycerol.

8. The process of claim 7, wherein the pH of the crude glycerol is raised to at least a pH of 9.

9. The process of claim 1 , wherein the contacting glycerol with heat under vac u below an evaporation point of the glycerol.

10. The process of claim 1 , wherein the contacting glycerol with heat: under vacuum is carried out in the presence of steam at a level of greater than 0.9 weight percent steam based on the weight of glycerol.

11 . The process of claim 1 , the contacting glycerol with heat under vacuum comprises evaporating the glycerol.

12. The process of claim 11 , further comprising condensing the evaporated glycerol and wherein at least one of the giycidoi and monochloropropandio!

contaminants is removed as a vapor phase.

13. The process of claim 1 , wherein the contacting glycerol with a solid comprises contacting glycerol with a solid selected from the group consisting of silica, cellulose, wood pulp, activated carbon, ion exchange resins, diatomaceous earth, and combinations of any thereof.

14. The process of claim 1 , wherein the ion exchange resin is selected from the group consisting of strong base ion exchange resins, weak base ion exchange resins, strong acid Ion exchange resins, weak acid ion exchange resins, mixed bed resins, nonfunctional resins, and combinations of any thereof.

15. The process of claim 14, wherein the contacting glycerol with an ion exchange resin further comprises heating the contacting the glycerol and ion exchange resin at a temperature greater than 20 °C.

16. The process of claim 14, further comprising regenerating the ion exchange resin.

17. The process of claim 14, further comprising contacting the glycerol with carbon,

18. The process of claim 14, wherein the glycerol Is contacted with a base ion exchange resin followed by contacting the glycerol with an acid ion exchange resin.

19. The process of any one of claims 1-18, wherein a content of a

monoohloropropanedioL the glycidol, or a combination of any thereof is less in the contacted glycerol than in the glycerol,

20. A product produced by the process of any one of claims 1 -19 for use in a product selected from the group consisting of food _: beverages, personal care products, oral care products, tobacco, pharmaceuticals, polyether polyols, propylene glycol, recreational vehicle fluids, per foods, alkyd resins, deicers, completion and fracture fluids, drilling muds, polyglycerols, concrete and asphalt lubrication, ep!chlorohydrin production and combinations of any thereof