Secondary Alcohol Ethoxylates - American Chemical Society

9 Secondary Alcohol Ethoxylates Physical Properties and Applications 1

Downloaded by NORTH CAROLINA STATE UNIV on June 26, 2013 | http://pubs.acs.org Publication Date: June 15, 1981 | doi: 10.1021/bk-1981-0159.ch009

NAOJI KURATA , KAZUO KOSHIDA, HIROMI YOKOYAMA, and TAKAKIYO GOTO Technical Department of Kawasaki Plant, Nippon Shokubai Kagaku Kogyo Co., Ltd., 10-12 Chidori-cho, Kawasaki-shi, Japan

Only a few companies in the world have produced surfactant range higher secondary alcohols until now. The first secondary alcohol plant appeared in the U.S.S.R. in 1959 and has been in operation since then. It has a capacity of about 10,000 tons per year of alcohols having carbon numbers ranging from 13 to 17. The alcohols are mainly used to produce sulfosuccinate esters through esterification with maleic anhydride followed by addition of sodium sulfite. The sulfosuccinate esters are used as raw materials for powder detergents there. Meanwhile, in 1964 in the U.S.A., Union Carbide Corporation commercialized a series of ethoxylated nonionic surfactants based on their secondary alcohols having carbon numbers ranging from 11 to 15 under the registered trade name of TERGITOL 15-S. The plant is believed to have a capacity of 36,000 tons per year of 3 mole ethoxylate of the alcohols. The third plant for higher secondary alcohols was constructed by Nippon Shokubai in Japan in 1972. The plant capacity, originally 12,000 tons per year of 3 mole ethoxylate, was expanded to 18,000 tons per year in 1977 and now is being further expanded to 30,000 tons per year. Nippon Shokubai's products are also sold mainly in the form of ethoxylate under the registered trade name of SOFTANOL. The alkyl carbon range of SOFTANOL is from 12 to 14 so far. All industries, especially the surfactant and detergent industries, have been heavily involved in various recent controversies such as health and safety problems, resource and energy conservation movements and so on. Under these circumstances, more emphasis has to be placed on key words: SAFETY, RESOURCE SAVING and EFFICIENCY. Only by satisfying these three will there be the chance of developing new technologies and new products. It is hoped that this presentation will give some ideas for more beneficial use of the products derived from higher secondary alcohols to those who are seeking new technical development in the surfactant and detergent industries. 1

Current Address: Nippon Shokubai K.K. Co., Ltd., Osaka-shi, Japan. 0097-6156/ 81 /0159-0113$ 11.25/0 © 1981 American Chemical Society

In Monohydric Alcohols; Wickson, E.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

114

MONOHYDRIC ALCOHOLS

R

0 ->

R - O - O - H

-)

R-O-H

H

B

°

2

)

[R-0-0-^-6^ I

> R - O - B - 0

2

or

C-'

R

+

U

0 0

+ U

0. +

H 0 2

R

^BOj

EO -> Catalyst)


(Acid

R-0-(CH CH 0) H 2

2

( n » l ~ 2 )

n

i

R-0-(CH CH 0) H 2

2

2

2

> R-0-(CH CH 0) /H

3

2

(Base

Figure 1.

R-0-(CH CH 0) H

Catalyst)

(

S

0

F

T

A

2

N

0

5

,

0

R-O-H

( n - 5 , 7 , 9,12 , — -)

n

_

L

+

3

-

7

0

,

-90,

- 120,

--)

Synthesis route to secondary alcohol ethoxylates from n-paraffins

n-PARAFFIN - METABORIC

M O L E C U L A R Oo

•AMMONIAC

Z3L

DEHYDRATION

ACID< BASE

AUXILIARY

CATALYST

J

OXIDATION

ESTERIFI CATION

SAPONIFICATION

m

PI S T I L L A T I O N

h2o

HYDRQLYSIS SEPARATION I

*i BORIC

ACID

WASHING W I T H

ETHYLENE

WATER

DISTILLATION

ACID

1

SECONDARY

-»|

ALCOHOL-

OXIDE

CATALYST

1

E T H Q X Y L A T I ON

I CATALYST 3-mole I

Figure 2.

RECOVERY

SAPONIFICATION

i

ETHOXYLATE

R E M O V A L "1

DISTILLATION

RECOVERED ALCOHOL

OXIDE

CATALYST

Simplified Nippon Shokubai's process route for secondary alcohols and their ethoxylates


9.

KURATA ET AL.

Secondary Alcohol Ethoxylates

115


Manufacturing Process of Secondary A l c o h o l s and Their Ethoxylates Since previous papers(1,2) describe d e t a i l s of the manuf a c t u r i n g process f o r secondary alcohols(SA) and t h e i r ethoxylates (SAE), only the o u t l i n e of the process w i l l be presented here. A mixture of secondary a l c o h o l s i s obtained by l i q u i d phase a i r o x i d a t i o n of normal p a r a f f i n s i n the presence o f a b o r i c a c i d c a t a l y s t ( F i g u r e 1 ) . Although the e x i s t i n g commercial processes, as developed independently, comprise s i g n i f i c a n t l y d i f f e r e n t comb i n a t i o n s of v a r i o u s u n i t processes, they are a l l based on t h i s b o r i c acid-modified o x i d a t i o n of hydrocarbons(3). In Nippon Shokubai s p r o c e s s ( F i g u r e 2 ) , the 3 mole e t h o x y l a t e of a mixture of secondary a l c o h o l s can be produced from a mixture of normal p a r a f f i n s through a f u l l y i n t e g r a t e d continuous process. The o x i d a t i o n i s c a r r i e d out u s i n g ^ - m e t a b o r i c a c i d as a c a t a l y s t and an ammoniac base as an a u x i l i a r y c a t a l y s t to promote the r e a c t i o n ( 4 ) . The a l c o h o l mixture obtained c o n s i s t s o f a l l p o s s i ble s t r u c t u r a l isomers of secondary a l c o h o l s having the same carbon numbers as the raw m a t e r i a l used. The e t h o x y l a t i o n of secondary a l c o h o l s must be f i r s t c a r r i e d out using an a c i d c a t a l y s t to a low degree of p o l y m e r i z a t i o n ( 2 ) . The product, 3 mole e t h o x y l a t e , i s separated from the r e a c t i o n mixture by s t r i p p i n g the unreacted a l c o h o l . F u r t h e r e t h o x y l a t i o n can then be c a r r i e d out j u s t as w i t h the primary a l c o h o l o r a l k y l phenol u s i n g a base c a t a l y s t i n the conventional manner. In t h i s process f o r 3 mole e t h o x y l a t e , a mixture o f n-paraff i n s having three successive carbon numbers can be used. The spread of four or more successive carbon numbers may cause d i f f i c u l t i e s i n the s e p a r a t i o n and p u r i f i c a t i o n steps. Table I shows up-to-date process economics f o r secondary a l c o h o l s and t h e i r 3 mole e t h o x y l a t e . f

Considerations of Carbon Number Ranges n - P a r a f f i n s are u s u a l l y i s o l a t e d from kerosene and have c a r bon numbers ranging from 10 t o 16. As a raw m a t e r i a l f o r Nippon Shokubai s SOFTANOL, 0^2-14 from the v i e w p o i n t s of feed stock a v a i l a b i l i t y and v e r s a t i l e performance of the products. Table I I shows a t y p i c a l example o f carbon number d i s t r i b u t i o n of n - p a r a f f i n s i n kerosene now a v a i l a b l e i n Japan. To u t i l i z e a l l n - p a r a f f i n s i n kerosene i n the near f u t u r e , i t i s conveni e n t to d i v i d e them,for i n s t a n c e , i n t o three f r a c t i o n s each having three successive carbon numbers, i . e . ^ 0 - 1 2 ^ * » ^12-14 (ave. 13), and C ^ ^ ( a v e . 15). Because o f great d i f f e r e n c e s i n t h e i r vapor p r e s s u r e s ( T a b l e HE), d i f f e r e n c e s i n the process v a r i a b l e s o r i g i n a t i n g from carbon number d i s t r i b u t i o n of raw m a t e r i a l s are r e l a t i v e l y great i n t h i s process, e s p e c i a l l y i n the o x i d a t i o n step. A comparison i s summar i z e d i n Table IV, which shows the disadvantage o f a lower carbon number range t o some extent. f

w

a

s

c n o s e n

a v e



116

MONOHYDRIC ALCOHOLS

Table I

Process Economics f o r C ^ Secondary A l c o h o l s and f o r Their 3-mole Ethoxylate

Raw M a t e r i a l and U t i l i t i e s Consumption, (per ton of product) Alcohol 1,240 kg

Normal P a r a f f i n s Ethylene Oxide Other Chemicals

10,000 yen

Steam Fuel E l e c t r i c Power Process Water Cooling Water I n e r t Gas

3.3 ton 500 3.3 600 10

kwh m m3 m 3

3

3-mole E t h o x y l a t e 750 kg 420 kg 8,000 yen 3.0 ton 400 2.5 500 10

kwh m3 m n.3 3

Commercial I n s t a l l a t i o n 12,000 tons/yr of j o 14 a r y A l c o h o l s and 18,000 tons/yr of 3-mole E t h o x y l a t e a t Nippon Shokubai s Kawasaki P l a n t , Japan. C

S e c o n d

?


9.

KURATA ET AL.

Table I I

117


T y p i c a l Example o f Carbon Number D i s t r i b u t i o n of n - P a r a f f i n s Extracted from Kerosene

Carbon Number Distribution^)

C

10 7

C

C

C

C

C

l l °12 1 3 1 4 1 5 1 6 25

24

22

6

15

1

Table HE Vapor Pressure and B o i l i n g P o i n t of n - P a r a f f i n s


Carbon Number Vapor Pressure at 170°C(torr)

380

130

44

B o i l i n g Point(°C)

196

235

271

T y p i c a l P h y s i c a l and Surface A c t i v e P r o p e r t i e s To examine the p h y s i c a l and surface a c t i v e p r o p e r t i e s of SAE, three secondary a l c o h o l samples each having three successive carbon numbers, as mentioned e a r i e r , were prepared. For p r a c t i c a l reasons, blends of a l c o h o l s are chosen i n s t e a d of a l c o h o l s having i n d i v i d u a l carbon numbers. The a l c o h o l samples were ethoxylated to v a r i o u s degrees of p o l y m e r i z a t i o n f o r t e s t i n g . Two previous papers by other workers are recommended w i t h reference t o t h i s s u b j e c t . One by MacFarland(5) of Union Carbide Corp. deals w i t h a blend of C ^ i - j ^ secondary a l c o h o l s and the other by Matson(6) of C o n t i n e n t a l O i l Co. deals w i t h i n d i v i d u a l carbon chain ~ homologs. Pour p o i n t , v i s c o s i t y , cloud p o i n t , w e t t i n g power and foam p r o p e r t i e s , being important advantages of SAE, are presented here i n comparison w i t h other commercial products d e r i v e d from primary a l c o h o l s ( Z i e g l e r and Oxo) or nonylphenol (branched chain). 1

Pour P o i n t . Figure 3 shows pour p o i n t s v s . G r i f f i n s HLB value f o r v a r i o u s ethoxylated n o n i o n i c s . SAE, i n g e n e r a l , have f a r lower pour p o i n t s than those of primary a l c o h o l s ( P A ) . Among three secondary a l c o h o l s e r i e s w i t h d i f f e r e n t carbon number ranges, the lower the carbon number range, the lower the pour p o i n t , e s p e c i a l l y i n the lower HLB or waterinsoluble region. Nonylphenol ethoxylates(NPE) have pour p o i n t s s i m i l a r t o those o f SAE i n the higher HLB r e g i o n but d i f f e r i n the HLB region below 10. Smith(7) and F i s h e r ( 8 ) r e c e n t l y published a r t i c l e s on the r e l a t i o n s h i p of v i s c o s i t y , pour p o i n t and a l k y l chain length of primary a l c o h o l ethoxylates(PAE) and SAE. The e m p i r i c a l equations proposed are i n f a i r l y good agreement w i t h the authors' obser-


118

MONOHYDRIC ALCOHOLS

Table IV Comparison of Process V a r i a b l e s w i t h D i f f e r e n t Carbon Number Ranges f o r the P r o d u c t i o n of Sec.-Alcohols Factors

Carbon Number Range of n - P a r a f f i n s


(Oxidation Step)

C

Reaction Temperature Reaction Pressure Conversion Selectivity Space Time Y i e l d

C

10 - 12

C

12

Normal Higher Lower Lower Lower

(Separation and P u r i f i c a t i o n Step) D i s t i l l a t i o n Temperature Lower D i s t i l l a t i o n Pressure Lower Manufacturing Cost

Table V

i n

1?

..

1 4

C

n "

Normal Normal

Higher Higher

Normal

Lower

27 8 9

3x103 1x10* 105 77 132 160 7 x l 0 130 40 230 l x l O 270 180 37 270 | G E L I 300

81 96 130

52 65 87

3 2 2

23 6 6

6xl0 lxlO 74 135 162 lxlO 35 218 2x10^ 258 30 229 | G E L I 227

100 123 176

77 93 126

52 61 87

4 3 3

28 715 6 37 8 53

15 x l 0 1x105 104 123 1 2x103 192 158 310

56 69

SAE(7E0) (9E0) (12E0)

N P E

Normal Lower Higher Higher Higher

50 64 94

7 4 5

+

Normal Normal Normal Normal Normal

65 81 114

SAE(7E0) (9E0) (12E0)

1 6

C

14 " 16

77 97 134

7 5 6

12 14 u .t 1

10 2 2 2

C

C

cP at 25°C Surfactant Concentration (% by weight) 60 90 100 70 80 20 30 40 50

SAE(7E0) (9E0) (12E0)

C

14

V i s c o s i t y and G e l Range of Aqueous S u r f a c t a n t Solutions

Surfactant C

Higher

C

P A E ( 7 E O )

(9E0) (12E0)

84 112 171

94 142 221

28 75 98 18 68 151 28 118 221

3

3

3

1

G E L

1

C £ t

1

G E L

4 4

4

I S O L I I

1

(8E0) 167 292 421 597 8 x l 0 7 x l 0 l x l O (10EO) 4 32 320 1 G E L ,| 2 x l 0 9 x l 0 (13E0) 882 2 6 40 1 GEL 1 3

4

3

5 4

2x10$ 274 404 290 306 408


232 257 279

9.

KURATA ET AL.


119

v a t i o n s on SAE w i t h i n the range of to and EO mole numbers of below 15. T h e i r equations can be used to p r e d i c t pour p o i n t o r v i s c o s i t y of SAE from t h e i r chemical s t r u c t u r e s . V i s c o s i t y . Figure 4 shows p l o t s of v i s c o s i t y at 25°C v s . EO mole numbers f o r the three s e r i e s of SAE. Here, the lower the carbon number range, the lower the v i s c o s i t y . PAE have much higher v i s c o s i t i e s than SAE having the same carbon number range. Thus, the v i s c o s i t y of i2+14 gl about the same as that of ^ 4 except i n the higher EO mole r e g i o n , where PAE (12E0) i s s o l i d at t h i s temperature. NPE have s t i l l higher v i s c o s i t i e s than SAE. As t o the v i s c o s i t y o f aqueous s o l u t i o n s of nonionic s u r f a c t a n t s , i n g e n e r a l , g e l formation tendency i s very important. Table V and Figure 5 show d i f f e r e n c e s i n v i s c o s i t y of aqueous s o l u t i o n s and g e l ranges f o r v a r i o u s n o n i o n i c s . Gel ranges o f SAE are remarkably narrow compared w i t h those of PAE and NPE(Table V). c


S

A

Z

i

e

e

r

P

A

E

i s

E

Cloud P o i n t . Figure 6 shows p l o t s of cloud p o i n t against G r i f f i n s * s HLB f o r v a r i o u s n o n i o n i c s . As the cloud p o i n t s o f the three s e r i e s of SAE are c l o s e l y on a l i n e w i t h i n t h i s HLB r e g i o n , the cloud p o i n t of a SAE can be estimated from a curve made w i t h other SAE having d i f f e r e n t a l k y l carbon number ranges. PAE have higher cloud p o i n t s than SAE a t the same HLB. This might mean that secondary a l k y l s behave as stronger hydrophobes than do primary a l k y l s . NPE have d i f f e r e n t slopes of cloud p o i n t vs. HLB curves compared w i t h a l c o h o l e t h o x y l a t e s . Wetting Power. Figure 7 shows p l o t s of w e t t i n g time against G r i f f i n ' s HLB f o r v a r i o u s n o n i o n i c s . B e t t e r w e t t i n g a b i l i t i e s of SAE compared w i t h PAE are seen as i n previous papers by MacFarland(_5) and by Z i k a O , 18). F i g u r e 8 shows temperature dependence of the w e t t i n g power of PAE, SAE and NPE each having about the same c a l c u l a t e d HLB. I t i n d i c a t e s a lower w e t t i n g power of PAE at lower temperatures and of NPE at higher temperatures compared w i t h that of SAE. Foam P r o p e r t i e s . A previous paper(1) reported that SAE show b e t t e r foam b r e a k a b i l i t y than PAE o r NPE. This tendency becomes c l e a r e r when SAE and PAE having lower carbon number ranges are compared. Figure 9 and F i g u r e 10 show foam volume v s . concent r a t i o n i n an a g i t a t i o n t e s t f o r Z^-lh ( ° ) ' 10-12 ^ °) anc Cg+n ( 8 E 0 ) i n the i n i t i a l stage and a f t e r f i v e minutes, r e s p e c t i v e l y . Figure 11 shows the time r e q u i r e d f o r 25% foam r e d u c t i o n vs. c o n c e n t r a t i o n of s u r f a c t a n t . I n these f i g u r e s , we can see that ^^Q_^2 P i d foam r e d u c t i o n at lower o r higher c o n c e n t r a t i o n . This should be a noteworthy phenomenon among v a r i o u s types of n o n i o n i c s u r f a c t a n t s and can be a p p l i e d i n the f o r m u l a t i o n of easy r i n s i n g detergents. A reason f o r such a maximum i n the curves of foam volume vs. c o n c e n t r a t i o n has not yet been found. S

A

E

9E

C

S A E

P A E

S

A

E

s n o w s

r a


9 E

120


MONOHYDRIC ALCOHOLS

Figure 4.

Viscosity vs. EO mole number for secondary alcohol ethoxylates

Secondary Alcohol Ethoxylates - American Chemical Society

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