5 Synthesis of High-Molecular Weight Polyether Polyols with · PDF file2 Complexation reaction...

177

Double metal cyanide (DMC) catalysts were developed 40 years ago by General Tire & Rubber [1]. These catalysts have the following general formula of a non-stoichiometric substance:

Zn Co(CN) ZnCl y Ligand zH O3 6 2 2 2# # #6 @ (5.1)

Instead of Co3+, very active catalysts were obtained with cyanocobaltate complexes of Fe, Cr, Pt, Ir [1–7]. These catalysts have a very high efficiency for propylene oxide (PO) polymerisation, initiated by hydroxyl groups, leading to high-molecular weight (MW) polyether polyols with very low unsaturation. The best DMC catalyst is based on zinc hexacyanocobaltate [2–47], combining the efficiency with the accessibility and low cost of raw materials. The DMC catalysts with the Structure 5.1 were obtained by the reaction of an aqueous solution of potassium hexacyanocobaltate K3[Co(CN)6] [1–7, 9–34] or of an aqueous solution of hexacyanocobaltic acid [2, 3, 37], with an aqueous solution of ZnCl2, at around 25–40 °C. The zinc hexacyanocobaltate precipitated as a white suspension:

3ZnCl 2K Co(CN)

3ZnCl 2H Co(CN)

Zn Co(CN) 6KCl

Zn Co(CN) 6HCl2 3 6

2 3 6

3 6 2

3 6 2

" .

" .

+

+

+

+

6 66 6

@ @@ @

(5.2)

A solution of ligand in water was added to the resulting suspension of Zn3[Co(CN)6]2. The most important ligands used are: dimethyl ether of ethylene glycol (EG) (glyme), dimethyl ether of diethylene glycol (diglyme), 1,4-dioxane, tert-butyl alcohol, EG mono tert-butyl ether, diethylene glycol mono tert-butyl ether, propylene glycol (PG) mono methyl ether, dipropylene glycol mono methyl ether, phosphorus compounds (phosphine oxides, phosphorus esters) dimethylsulfoxide, dimethylacetamide, N-methyl pyrolidone, polypropylene glycols (PPG), polyethylene glycols (PEG), polytetrahydrofuran and polyester polyols [8–10, 12–29, 32–39, 48–50].

5 Synthesis of High-Molecular Weight Polyether Polyols with Double Metal Cyanide Catalysts

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Chemistry and Technology of Polyols for Polyurethanes, 2nd Edition, Volume 1

The resulting solid complex catalyst was separated by filtration (or by centrifugation). In order to eliminate as much as possible of the resulting potassium chloride, which has an inhibitory effect in PO polymerisation, the solid was reslurried in a mixture of ligand- water and finally in pure ligand and then filtered. The catalyst was dried at moderate temperatures (60–70 °C) and under vacuum (665–1,330 Pa), for several hours. The catalytic activity of the catalyst increases substantially if the water content in the final catalyst is very low, water having an inhibitory effect on PO polymerisation. The analysis of the best catalysts proved that water is always present, around 0.5-1 mol of water/mol of catalyst (z = 0.5–1 in Structure 5.1). The catalysts with the general formula shown in Structure 5.1 synthesised with 1,2-dimethoxy ethane as ligand, were considered for many years a standard model for DMC catalysts [2, 51, 52]. The flow diagram for synthesis of DMC catalysts is presented in Figure 5.1.

The double-bond content of polyether polyols synthesised with the standard DMC catalyst is very low, around 0.015–0.02 mequiv/g at a MW of 6,000–6,500 daltons. Very high catalytic activity DMC catalysts were obtained using tert-butyl alcohol as ligand or with combinations of ligands such as: tert-butyl alcohol – PPG (MW = 1,000-4,000), tert-butyl alcohol – PEG (preferred MW = 2,000), tert-butyl alcohol – sorbitans, tert-butyl alcohol – polytetramethylene glycols, tert-butyl alcohol – tert-butoxy ethanol [17, 32], tert-butyl alcohol – hydroxyethyl pyrolidone, tert-butyl alcohol - poly(N-vinyl pyrolidone), tert-butyl alcohol – alkyl (polyglucosides) [8–10, 12 –29, 32–39, 48–50].

These catalysts lead to an extremely low unsaturation, of around 0.005 mequiv/g, impossible to obtain with other catalysts.

In Figure 5.2 one observes the unsaturation increase versus the polyether MW for potassium hydroxide (KOH), compared with DMC catalysts.

A high unsaturation proved a high concentration in polyether monols and, as an immediate consequence, the functionality (f) of the resulting polyether triols is much lower than 3 OH groups/mol. Thus, a polyether triol of MW of 6,000 daltons, obtained with KOH, has a functionality of 2.14-2.21 OH groups/mol, much lower than that of polyether triols (2.94 OH groups/mol) obtained with DMC catalysts. The effect is very important in polyether diols. A polyether diol with a MW of 4,000 daltons, obtained by anionic polymerisation has a functionality of 1.61 OH groups/mol, but a polyether diol obtained with DMC catalysts has a functionality close to the theoretical functionality (f = 1.98–2.00 OH groups/mol).

The polyurethane (PU) elastomers obtained from polyether diols with DMC catalysts (Acclaim Polyols of Bayer) have a spectacular improvement in the majority of physico-

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Synthesis of High-Molecular Weight Polyether Polyols with Double Metal Cyanide Catalysts

mechanical properties when compared with PU elastomers made from the polyether diols, obtained by anionic catalysis.

ZnCl2 Water

Water Precipitation of Zn3[Co(CN)6]2

Complexation reaction

Filtrate

Filtrate

Filtrate

Water,

ligand

Filtration 1

Filtration 2

Filtration 3

Drying

Reslurry 1

Reslurry 2

Ligand

WaterK3[Co(CN)6]

Solution 2Solution 1

DMC catalyst

Figure 5.1 Flow diagram for synthesis of DMC catalysts

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0.1

1,000

0.2

0.3

0.40.5

0.6

0.7

Uns

atur

atio

n m

equi

v/g 0.8

0.9

1.0

2,000 3,0004,000

DMC catalysts

KOH

MW (daltons)

5,000 6,000 7,000

Figure 5.2 The polyether triol unsaturation obtained with DMC catalysts, compared with that obtained with KOH

Table 5.1 shows the double-bond content and the functionality of polyether triols, with a MW of 6,000 daltons, synthesised with different catalysts.

DMC catalysts are real heterogeneous coordinative catalysts [2, 51, 52]. At the end of polymerisation, the catalyst is dispersed in the liquid polyether polyols in the form of small solid particles of around 200 nm (0.2 μm) diameter. By dilution with n-hexane and filtration, it is possible to achieve a quantitative removal of the DMC catalyst [51, 52].

It is very interesting that pure crystals of Zn2[Co(CN)6]2 are catalytically inactive in PO polymerisation [6, 7]. It is only in the presence of an excess of ZnCl2 and in the presence of ligands that the catalyst becomes very active catalytically.

X-ray diffraction studies proved that DMC catalysts, similar to many non-stoichiometric chemical substances, have many defects and vacancies in the crystalline structure [62]. These defects and vacancies are very strong coordination points. The oxiranic monomer is strongly coordinated by these centres at the oxygen atom and is transformed in a much more reactive structure than the uncoordinated monomer.

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This activation of the monomer by coordination explains the very high catalytic activity of DMC catalysts.

Table 5.1 The double-bond content of polyether triols synthesised with various alkoxylation catalysts

Catalyst Mechanism Unsaturation (mequiv/g)

Functionality (OH groups/mol)

References

KOH Anionic 0.09–0.1 2.14–2.21 [2]

CsOH Anionic 0.045–0.055 2.46–2.55 [53]

Ba(OH)2 Anionic 0.03–0.04 2.60–2.68 [54–56]

Phosphazene Anionic 0.018–0.02 2.78–2.8 [57–61]

DMC Coordinative 0.005 2.94 [18–20]

The alkylene oxide polymerisation, catalysed by DMC catalysts, is characterised by some specific points:

a) The first characteristic is an induction period that varies from 20–30 min to several hours. In this period of time, the consumption rate of PO is extremely low. After the induction period, the polymerisation rate of PO becomes extremely high and the catalyst is considered activated [1-52]. This behaviour is observed in Figure 5.3, where a typical curve for PO consumption in a PO polymerisation reaction catalysed by DMC catalyst is presented and compared with the reaction obtained with a classical KOH catalyst.

A possible explanation of the induction period is the substitution of the soft ligands from the crystalline structure with PO that are in excess. After the induction period, the PO polymerisation rate is so high that in 1 to 3 h it is possible to add all the PO that is needed for the reaction. As a comparison, the polymerisation time, in the presence of KOH, is around 7–11 h.

A very efficient method to avoid a long induction period is to obtain an ‘activated masterbatch’ of DMC catalyst. Thus, a quantity of DMC catalyst, 10–20 times higher than for normal PO polymerisation, is suspended in a purified polyether polyol used as starter (e.g., a polyether triol with a MW = 650–700 daltons) [51, 52]. To this suspension of DMC catalyst is added a quantity of PO, and the mixture is stirred under pressure (200–400 MPa), at 105–120 °C, until the pressure begins to decrease

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rapidly. A concentrated suspension of an ‘activated’ DMC catalyst was obtained. By using a part of this ‘activated masterbatch’ in normal PO polymerisation, the PO consumption starts immediately, without any induction period (Figure 5.4).

100

200

300

ml P

O r

eact

ed

400

500

600

700

800

00 60 120 180 240

Time (min)

KOH

DMCcatalyst

Inductionperiod

300 360 420

Figure 5.3 The PO consumption versus time in PO polymerisation with DMC catalysts and classical KOH catalyst. Temperature: 110 °C; pressure: 300 MPa; catalyst concentration: [KOH] = 0.25%; and DMC catalyst: 200 ppm (0.02%)

With the synthesised ‘activated masterbatch’ of DMC catalyst it is possible to make 10–20 normal PO polymerisation reactions, leading to a considerable economy of time, due to the absence of the induction period, corresponding to each batch.

b) Another important characteristic of PO polymerisation with DMC catalysts is the impossibility of initiating the reaction by direct addition of PO to a starter such as glycerol or 1,2-PG [1–7, 51, 52]. The explanation of this abnormal behaviour is given by the formation of very strong, stable and inactive zinc chelates, with the 1,2-glycol structure of the starters (Structure 5.3). This is explained by the fact that water has an inhibitory effect on PO polymerisation with DMC catalysts. During PO polymerisation, water reacts with PO and is transformed into 1,2-PG, which blocks the activity of DMC catalyst by the formation of strong, catalytically inactive zinc chelates.

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100

200

300

ml P

O r

eact

ed

400

500

600

700

800

00 60 120 180 240

Time (min)300 360 420

KOH

DMCcatalyst

DMC catalyst,‘activatedmasterbatch’

Figure 5.4 The elimination of the induction period in PO polymerisation using an ‘activated masterbatch’ of DMC catalyst. Temperature: 110 °C;

pressure: 300 MPa; catalyst concentration: [KOH] = 0.25%; and DMC catalyst: 200 ppm (0.02%)

The formation of inactive zinc chelates mentioned before is shown in the following reaction:

CH2

HO

HO

1,2-PG

CHZn++

X

X

+ +CH3

Zn++CH2

2HCl

O

O

Zn chelate

CH CH3

(5.3)

The only possible way to initiate the PO polymerisation reaction catalysed by DMC catalysts is to use as starters, instead of pure polyols (e.g., glycerol, PG and so on), the low-MW PO adducts to these pure polyols. By propoxylating pure polyols with 1-3 PO units/hydroxyl groups, the possibility of 1,2-gycol structure generation

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disappears, because the distance between the new hydroxyl groups formed is too big to make a chelate. As an immediate consequence, the low-MW propoxylated polyethers, diols or triols, with a MW of 400–700 daltons are excellent initiators for PO polymerisation with DMC catalysts. There are some synthesis variants of these low-MW propoxylated starters, avoiding the purification step. One method is to use the PO polymerisation, initiated by glycerol and catalysed by magnesium oxide or by hydrotalcite followed by simple filtration [64]. Another variant is to obtain a low-MW adduct of PO for the polyolic starters, by cationic PO polymerisation catalysed with Lewis acids such as BF3, SbF5 or Y(CF3SO3)3 [10, 38] or Brönstedt acids, such as CF3SO3H, HBF4, HPF6, HSbF6 [39], but generally at lower temperatures. To the synthesised low-MW polyol, containing the acidic catalyst, the DMC catalyst is added and the coordinative PO polymerisation continues at higher temperatures (105–130 °C) to high-MW polyether polyols. It was observed that the acids (organic or inorganic) do not have any inhibitory effect on PO polymerisation with DMC catalysts [33, 41]. It is possible to start the PO polymerisation reaction with organic acids such as fumaric acid [63]. On the other hand, the basic substances such as: trialkylamines, alkali hydroxides and alkaly alcoholates strongly inhibit the catalytic activity of DMC catalysts.

The stepwise addition of starter together with PO is a practical method to obtain a high-MW polyether directly from glycerol or 1,2-PG, without needing to first obtain a propoxylated oligomer [27-29]. This variant of continuous starter addition was proved not to markedly affect the MWD of the resulting polyether, which is narrow [29].

Another variant is to use a very large excess of PO compared to the starter, to initiate the PO coordinative polymerisation directly from the starter, e.g., a gravimetric excess of 60–90 parts of PO/1 part of trimethylolpropane [41].

The fact that the acids do not inhibit the catalytic activity of DMC catalysts, and basic substances have a strong inhibitory effect, leads to the idea that the nature of PO polymerisation with DMC catalysts is cationic coordinative and not anionic coordinative.

It is possible to make an analogy between PO polymerisation by cationic mechanism (activated monomer mechanism, Section 4.12) and PO polymerisation with DMC catalysts. Thus, in cationic polymerisation the monomer is activated by the formation of secondary oxonium cations by interaction with a proton and in DMC catalysts the monomer is activated by strong coordination (Figure 5.5).

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CH2

δCH

O+

+ δ +

H

(I)

CH3

CH2

Zn++

δCH

O

+ δ +

δ -

(II)

CH3

Figure 5.5 The activated monomer structures in cationic polymerisation (I) and in coordinative polymerisation with DMC catalysts (II)

In both PO activated structures, the electron density at the carbon atoms of the oxiranic ring decreases (in one case due to a neighbouring positive charge, in the second by coordination) and makes possible a nucleophilic attack of a weak nucleophile, such as the oxygen atom of hydroxyl groups. To conclude, the mechanism of PO polymerisation with DMC catalyst is based on the repeated nucleophilic attack of hydroxyl groups on the carbon atoms of PO, strongly activated by coordination (Structures 5.4 and 5.5):

CH3CH3

CH

H+

O+

H

CH2

H

R

Activated PO(oxonium cation)

Cationic polymerisation

O+ OHH2C CH

H

R

O

CH3

CHCH2

R

O OH +

+

(5.4)

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CH3

CH

-OO

CH2

H

R

Activated POby coordination

Coordinative polymerisation

OCH2

δ+

δ--

CH3

CH

H

R

O+ +

Zn++

Zn++

Zn++

CH3

CH

OH

CH2

R

O

CH3

CH +

OH

CH2

R

O

Zn++ (5.5)

A very similar mechanism for PO polymerisation with DMC catalysts was investigated by Xiaohua and co-workers [65] and Chen and co-workers [66, 67]. They proved that the coordination number of Zn2+ increases from 3 to 5.7 in the process of activation with PO. One considered that 5 oxygen atoms coordinate the Zn2+ ion and the sixth position is probably a vacancy of strong coordination power (Structure 5.6). The PO is activated by coordination in this position and the ring of the activated PO is opened by the reaction with hydroxyl groups (Structure 5.6):

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N

N

ZnO

+

+O

OCH3

CH

O

CH3

CH2

+

CH3

CH3

O

O

O

ZnO

O

O

H

O

O

N

N

ZnOO

O

CHCH2

CH3CH

CH2

CH3

CH3CH2

CH3

CH

O

O

ZnO

OO

O H

H

O

O

CH

OH

etc.R

CH2

CH3

O

(5.6)

An important characteristic of alkylene oxide polymerisation with DMC catalysts is the very low reaction rates obtained in ethylene oxide (EO) coordinative polymerisation. EO, which is much more reactive than PO in anionic polymerisation, is less reactive than PO in the coordinative polymerisation [35, 68]. A possible explanation of this behaviour is the fact that PO is a more basic monomer than EO due to the electron release effect of the methyl substituent in the oxiranic ring (the electron density at the oxygen atom of the PO ring is higher than that in the EO ring). As an immediate consequence, PO, is more basic, and is more strongly coordinated (and more strongly activated too) to the active sites of DMC catalysts than EO, the less basic monomer.

The synthesis of block copolymers PO–EO with a terminal poly[EO] block is practically impossible, cloudy polyols always being formed, with a very low ethoxylation rate. The formation of cloudy polyols is because of an unfavourable (non-uniform) distribution of EO units per hydroxyl groups. As a consequence of this non-uniform distribution, longer poly[EO] chains (having more than 10 EO units) are formed, which are derived from some hydroxyl groups, which crystallise and precipitate at room temperature, as a separate phase, in the liquid polypropylene oxide (PPO) matrix and the polyether polyol becomes cloudy. The short poly[EO] chains, with less than 10 EO units per

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hydroxyl group, are liquid at room temperature and do not have any tendency to crystallise and as an immediate consequence the resulting polyether is transparent. The short poly[EO] chains are formed as a consequence of an uniform distribution of EO per hydroxyl group and depends on the catalyst nature (using KOH or CsOH as catalyst but not DMC catalysts).

Excellent PO–EO block copolyether polyols with terminal poly[EO] block, are formed by the addition, to the intermediate propoxylated polyether obtained with DMC catalysts, of an anionic catalyst (KOH or potassium alcoholates) followed by the addition of EO by classical technology, via an anionic mechanism. By this relatively complicated route, it is possible to obtain PO–EO block copolymers with high primary hydroxyl content and very low unsaturation.

Fortunately, the mixture PO–EO (having, for example, 10–20% EO) reacts quantitatively in the presence of DMC catalysts and it is possible to obtain random PO–EO copolyether polyols by this synthetic route.

An important characteristic of PO polymerisation with DMC catalysts is the formation of very high-MW PPO (MW = 100,000–400,000 daltons), in very small quantities (100–400 ppm) which have a dramatic antifoaming effect in flexible PU foams [33, 43]. The flexible PU foams made with polyether triols obtained with DMC catalysts, containing traces of very high-MW PPO, collapse. The formation of these very high-MW PPO is inhibited by the modification of DMC catalysts with some additives such as inorganic acids [33, 41] or chlorosilanes [43]. The explanation of the formation of these high-MW polyethers is the presence of small quantities of Zn–OH bonds in all DMC catalysts. By blocking these Zn–OH bonds with acids or with chlorosilanes, the formation of the very high-MW polyethers was inhibited:

Zn OH HX Zn X H O

Zn OH Cl Si(CH ) Zn O Si(CH ) HCl2

3 3 3 3

"

"

- - + - - +

- - + - - - - + (5.7)

The utilisation of a PO with EO mixture (e.g., with 17–18% EO) strongly diminishes the antifoaming effect of the very high-MW polyether formed.

The molecular weight distribution (MWD) of propoxylated polyethers, obtained with DMC catalysts, is narrow. The MWD is broader at higher-MW polyethers (MW = 10,000–12,000 daltons), but at a MW of 5,000–6,000 daltons the MWD is narrow (MW/number average MW = 1.02–1.2). A method to obtain a narrow MWD is to

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use a very slow PO addition to the reaction mass (in fact a PO polymerisation at lower pressure). A high momentary excess of monomer (e.g., a polymerisation with all the PO at the beginning) leads to a broad MWD of the resultant polyether [2].

The very high catalytic activity of DMC catalysts for PO coordinative polymerisation initiated by hydroxyl groups causes a substantial decrease of the catalyst concentration, until very low levels of around 25–50 ppm (0.0025–0.005%) are reached [21–26, 32]. At this level of catalyst concentration, reasonable reaction times are obtained including a reasonable induction period – as an immediate consequence the polyethers containing DMC catalysts can be used in PU (elastomers, sealants, adhesives, elastomers), without purification. The possibility of eliminating the purification step is of great technological importance. The plant and the process themselves are more simple and the yield in polyether is very high (98–99%).

DMC catalysts are considered to be the ones that perform best at this time for PO polymerisation initiated by hydroxyl groups.

5.1 Continuous Process for Synthesis of Polyether Polyols with a Double Metal Cyanide Catalyst (IMPACT Catalyst Technology, a Greener Polyether Polyols Process)

Bayer developed the first continuous process for the synthesis of polyether polyols with DMC catalysts (IMPACT Catalyst Technology). In a short and simple production cycle, a large variety of polyether diols of very low unsaturation for elastomers, sealants, coatings as well as low monol content destined for flexible PU foams can be obtained. This has been one of the most important developments in the field of synthesis of polyether polyols [2, 69, 70]. As mentioned previously, this continuous process is characterised by its simplicity, high reaction rates, high yield, high productivity, an absence of purification steps, and by the possibility of addition of low-MW starters (glycerol or PG), together with a high excess of PO.

Bayer scientists studied the kinetics of PO polymerisation catalysed by DMC and demonstrated that they were unusual: ‘catch-up kinetics’. Those kinetic studies led to two discoveries of enormous practical importance:

a) Low-MW starters (glycerol or PG) can be propoxylated in the presence of DMC catalysts if the concentration of these starters is maintained below a critical level.

b) Polymerisation of PO catalysed by DMC catalysts is strongly dependent on the equivalent weight (EW) of the starters, with low-EW polyether polyols being propoxylated preferentially.

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As mentioned previously, polymerisation of PO by stepwise addition to a mixture of low-MW starters (glycerol or PG) and DMC catalyst is not possible. PO polymerisation can start only if a propoxylated glycerol (or propoxylated PG) with a hydroxyl number (OH#) of 400–600 mg KOH/g is used as a starter. It has been demonstrated that DMC catalysts can catalyse the alkoxylation of low-MW starters (glycerol or PG) if these low-MW starters are added continuously and slowly, together with a large excess of PO or as a mixture with PO (only at 2–5% concentration). In this way, the quantity of propoxylated glycerol used normally as starter is diminished substantially or is eliminated. Bayer scientists discovered that if the concentration of glycerol or PG is maintained below a critical level, then polyaddition of PO to these polyols is carried out normally at a high reaction rate and without deactivation of catalysts [69, 70].

The determining factor in PO polymerisation with DMC catalysts is the EW (not the MW). Thus, if a mixture of a diol of 500 MW with a diol of MW = 2,000 is propoxylated in the presence of DMC catalysts, PO reacts almost exclusively with the diol of MW = 500 (lowest EW = 250) and does not react with the diol of MW = 2,000 (highest EW = 1,000). If the MW of a diol resulting exclusively by propoxylation of a diol of MW = 500 becomes MW = 2,000, then both the initial diol of MW = 2,000 and the newly formed diol of MW = 2,000 are propoxylated together, leading to a polyether diol of narrow MWD. If two polyether polyols of different MW, but with the same EW (i.e., a triol of MW = 3,000 and a monol of MW = 1,500, both having EW = 1,500) are propoxylated together in the presence of DMC catalysts, both polyethers react with PO. This phenomenon occurs because the polyol with the lowest EW has a higher concentration of hydroxyl groups, and these hydroxyl groups are complexed preferentially to the active sites of the catalysts. Equilibrium is established between hydroxyl groups and the active centres of catalysts, with species having high OH# favoured in this type of complexation. This rapid equilibrium in favour of species with high OH# explains why the polyol with the lowest EW undergoes propoxylation preferentially [69, 70]. Considering this important discovery that polyols with low EW react preferentially with PO, the reaction can be started with a slurry of DMC catalyst in a polyol of MW = 1,000 prepared with a DMC catalyst, followed by addition of a mixture of PO with glycerol (ratio of PO/glycerol is adjusted as a function of desired MW). In this way, it is not necessary to use a starter for a polyether prepared with KOH as a catalyst. IMPACT is a green technology because energy consumption is low compared with KOH-catalysed technology, and it is a high-yield process that does not create solid waste.

The very intensive research work carried out in recent years in the area of DMC catalysts by ARCO, Lyondell, BAYER, DOW, ASAHI, OLIN, ARCH, and BASF represents fundamental and highly important contributions to the synthesis of high-performance polyether polyols for PU.

191


References

1. J. Milgrom, inventor; The General Tire & Rubber assignee; US3278457, 1966.

2. R.J. Herold and R.A. Livigni, Polymer Preprints, 1972, 13, 1, 545.

3. R. Herold and R. Livigni in Polymerisation Kinetics and Technology, Ed., N.A.J. Platzer, Advances in Chemistry Series No.128, American Chemical Society, Washington, DC, USA, 1973, p.208.

4. J. Herold, Macromolecular Synthesis, 1974, 5, 9.

5. R.A. Livigni, R.J. Herold, O.C. Elmer and S.L. Aggarwal in Polyethers, Ed., E.J. Vandenberg, American Chemical Society Symposium No.6, ACS, Washington, DC, USA, 1975.

6. J. Kuyper and G. Boxhoorn, Journal of Catalysis, 1987, 105, 1, 163.

7. D.F. Mullica, W.O. Milligan, G.W. Beall and W.L. Reeves, Acta Crystallography, 1978, B34, 12, 3558.

8. T. Hiromitsu, O. Shigeyuki, I. Masaki and Y. Shigeaki, inventors; Asahi Glass Co., Ltd., assignee; JP3115430A2, 1919.

9. J.T. Ruszkay, inventor; Arco Chemical Technology, assignee; US5416241, 1995.

10. J.W. Reisch, M.M. Martinez and M. Raes, inventors; Olin Corporation, assignee; US5144093, 1992.

11. C. Smith, J.W. Reisch and J.M. O’Connor, Journal of Elastomers Plastics, 1992, 24, 4, 306.

12. B. Le-Khac, inventor; Arco Chemical Technology, assignee; EP654302A1, 1995.

13. B. Le-Khac, P.T. Bowman and H.R. Hinney, inventors; Arco Chemical Technology, assignee; EP743093, 1996.

14. B. Le-Khac, H.R. Hinney and P.T. Bowman, inventors; Arco Chemical Technology, assignee; US5627122, 1997.

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15. J. Hoffmann, P. Gupta, H. Pielartzik, P. Ooms and W. Schäfer, inventors; Bayer, assignee; EP892002A1, 1999.

16. G.H. Grosch, H. Larbig, R. Lorenz, D. Junge, E. Gehrer and U. Trueling, inventors; BASF assignee; WO99/16775, 1997.

17. Y. Kazuhiko and T. Hiromitsu, inventors; Asahi Glass, assignee; JP4145123, 1990.


19. B. Le-Khac, inventor; Arco Chemical Technology, assignee; EP761708A3, 1997


21. B. Le-Khac, inventor; Arco Chemie Technologie Nederland, assignee; WO9816310A1, 1998.

22. B. Le-Khac, inventor; Arco Chemical Technology, assignee; US5693584, 1997.

23. J. Hoffmann, P. Gupta, R-J. Kumpf, P. Ooms and W. Schafer, inventors; Bayer, assignee; WO9919062A1, 1999.

24. J. Hoffmann, P. Gupta, R-J. Kumpf, P. Ooms, W. Schafer and M. Schneider, inventors; Bayer, assignee; WO9919063A1, 1999.

25. J. Hoffmann, P. Ooms, P. Gupta, M. Schneider and W. Schafer, inventors; Bayer AG, assignee; WO99/33562A1, 1999.

26. J. Hoffmann, P. Ooms, P. Gupta and W. Schafer, inventors; Bayer AG, assignee; WO9946042, 1999.

27. P.T. Bowman, H.R. Hinney and R.L. Meeker, inventors; Arco Chemical Technology, assignee; US5714639, 1998.

28. B. Le-Khac, H.R. Hinney and P.T. Bowman, inventors; Arco Chemical Technology, assignee; US5780584, 1998

29. J.F. Pazos and T.T. Shih, inventors; Arco Chemical Technology, assignee; US5689012, 1997.

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30. Plastics Technology, 1999, 45, 3, 67.

31. Chemical Engineering, 1999, 106, 12, 94.

32. K. Sugiyama, H. Fukuda, A, Horie and H. Wada, inventors; Asahi Glass Company, assignee; EP1022300B1, 2004.

33. B. Le-Khac, W. Wang and M.K. Faraj, inventors; Arco Chemical Technology, assignee; US6063897, 2000.

34. R.M. Wehmeyer, inventor; Dow Global Technologies Inc., assignee; US6429166, 2002.

35. K.S. Clement, L.L. Walker, R.M. Wehmeyer, R.H. Whitmarsh, D.C. Molzahn, W.P. Diaris and D.E. Laycock, inventors; Dow Global Technologies Inc., assignee; US6429342, 2002.

36. P. Ooms, J. Hoffmann and P. Gupta, inventors; Bayer AG, assignee; US6468939, 2002.

37. G.H. Grosch, H. Larbig, R. Lorenz, D. Junge and K. Harre, inventors; BASF AG, assignee; US6441247, 2002.

38. J. Hoffmann and P. Gupta, inventors; Bayer AG, assignee; US6482993, 2002.

39. K.B. Chandalia, J.W. Reisch and M.M. Martinez, inventors; Olin Corporation, assignee; US5391722, 1995.

40. T. Watabe, H. Takeyasu, T. Doi and N. Kunii, inventors; Asahi Glass Company, Ltd., assignee; EP0383333, 1990.

41. J.M. O’Connor and R.L. Grieve, inventors; Synuthane International Inc., assignee; WO0183107A3, 2001.

42. L.E. Katz and J.W. Reisch, inventors; Olin Corporation, assignee; US5099075, 1992.

43. M.K. Faraj, inventor; Arco Chemical Technology, assignee; US6051680, 2000.

44. D.E. Laycok, K.L. Flagler and R.J. Gulotty, Jr., inventors; Dow Chemical Company, assignee; US6376645, 2002.

45. D.E. Laycok and K.L. Flagler, inventors; Dow Chemical Company, assignee; US6358877, 2002.

194


46. B. Le-Khac, inventor; Bayer Antwerp NV, assignee; US6211330, 2001.

47. D.E. Laycok, K.L. Flagler and R.J. Gulotty, Jr., inventors; Dow Chemical Company, assignee; US6388048, 2002.

48. E. Baum, S. Bauer, K. Harre, G. Tischer, G-H. Grosch, R. Pretzsch, T. Ostrowski, M.J. Pcolinski, S. Dinsch, I. Rotermund and R. Lorenz, inventors; BASF AG, assignee; DE19949091, 2001.

49. J. Kim, J-T. Ahn, C.S. Ha, C.S. Yang and I. Park, Polymer, 2003, 44, 11, 3417.

50. I. Kim, J-T. Ahn, I. Park and S. Lee in Proceedings of the API Annual Technical/Marketing Conference, Polyurethanes, 2002, Salt Lake City, UT, USA, 2002, p.583.

51. J. Schuchardt and S. Harper in Proceedings of the 32nd Annual Polyurethane Technical Marketing Conference, San Francisco, CA, USA, 1989, p.360.

52. J.W. Reisch and D.M. Capone, Elastomerics, 1991, 123, 4, 18.

53. Y. Fukazawa and T. Hashimoto, inventors; Asahi Chemical Industry Co., Ltd., assignee; JP9040796, 1997.

54. A.J. Heuvelsland, inventor; The Dow Chemical Company, assignee; US5114619, 1992.

55. A.J. Heuvelsland, inventor; The Dow Chemical Company, assignee; US5070125, 1991.

56. W. Reich, E. Beck, E. Keil, U. Jager, M. Lokai, W. Fries and E. Ambach, inventors; BASF, assignee; EP737121, 1997.

57. M. Kouno, K. Mizutani, T. Nobori and U. Takaki, inventors; Mitsui Toatsu Chemicals, Inc., assignee; EP0763555A2, 1997.

58. T. Nobori, T. Suzuki, S. Kiyano, M. Kouno, K. Mizutani, Y. Sonobe and U. Takaki, inventors; Mitsui Toatsu Chemicals, Inc., assignee; EP0791600A1, 1997.

59. S. Yamasaki, Y. Hara, S. Yamura, F. Yamazaki, H. Watanabe, M. Matsufuji, S. Matsumoto, A. Izukawa, M. Aoki, T. Nobori and U. Takaki, inventors; Mitsui Toatsu Chemicals, Inc., assignee; EP0916686A1, 1999.

195


60. M. Isobe, K. Ohkubo, S. Sakai, U. Takaki, T. Nobori, T. Izukawa, and S. Yamasole, inventors; Mitsui Toatsu Chemicals, Inc., assignee; EP0897940A2, 1999.

61. T. Hayashi, K. Funaki, A. Shibahara, K. Mizutani, I. Hara, S. Kiyono, T. Nobori and U. Takaki, inventors; Mitsui Toatsu Chemicals, Inc., assignee; EP0950679A2, 1999.

62. F.E. Bailey, Jr., and J.V. Koleske in Alkylene Oxides and Their Polymers, Marcel Dekker, New York, NY, USA, 1991, p.76.

63. D.E. Laycock, R.J. Collacott, D.A. Skelton and M.F. Tchir, Journal of Catalysis, 1991, 130, 2, 354.

64. J. Shen, K.G. McDaniel, J.E. Hayes, U.B. Holeschouskyu and H.R. Hinney, inventors; Arco Chemical Technology, assignee; US5990232, 1999.

65. L. Xiaohua, K. Maoqing, W. Xinkui, China Synthetic Rubber Industry, 2001, 24, 3, 147.

66. S. Chen and L. Chen in Proceedings of the API Annual Technical and Marketing Conference, Polyurethanes, 2002, Salt Lake City, UT, USA, 2002, p.681.

67. S. Chen, N. Xu and J. Shi, Progress in Organic Coatings, 2004, 49, 2, 125.

68. K.S. Clement, L.L. Walker, R.M. Wehmeyer, R.H. Whitmarsh, D.C. Molzahn, W.P. Diaris, D.E. Laycock, J.W. Weston and R.J. Elwell, inventors; Dow Global Technologies Inc., assignee; US6642423, 2003.

69. J. Reese, K. McDaniel, R. Lenhan, R. Gastinger and M. Morrison in Proceedings of the 13th American Chemical Society Annual Green Chemistry & Engineering Conference, University of Maryland, MD, USA, American Chemical Society, Washington, DC, USA, 23–25th June, 2009.http://acs.confex.com/acs/green09/recordingredirect.cgi/id/489

70. K.G. McDaniel, inventor; Bayer Materials Science LLC, assignee; US2008167501, 2008.

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