DEVELOPMENT OF LUBRICATING OILS SUITABLE FOR USE WITH LIQUID OXIDIZERS
QUARTERLY PROGRESS REPORT NO. 3 1 June 1970 - 31 August 1970
Contract NAS8-25510 Control DCN l-X-50-20131(1F)
MRI Project No. 3380-C
For
National Aeronautics and Space Administration George C. Marshall Space Flight Center
Marshall Space Flight Center, Alabama 35812
Attn: A&TS-PR-M
https://ntrs.nasa.gov/search.jsp?R=19710001944 2018-08-29T13:33:15+00:00Z
DEVELOPMENT OF LUBRICATING OILS SUITABLE FOR USE WITH L I Q U I D OXIDIZERS
L. W. Breed R. L. E l l i o t t
QUARTERLY PROGRESS REPORT NO, 3 1 June 1970 - 31 August 1970
Cont rac t NAS8-25510 Cont ro l DCN l-X-50-20131(1F)
MRI P r o j e c t No. 3380-C
For
Nat iona l Aeronaut ics and Space Adminis t ra t ion
Marshall Space F l i g h t Center , Alabama 35812 George C. Marshal l Space F l i g h t Center
Attn: AScTS-PR-M
MtDWEST RESEARCF! BWiTlTUTE 425 VOLKER BOULEVARD, KANSAS CITY, MISSOURI 6411 0 Q AREA 816 561-0202
PREFACE
This r e p o r t w a s prepared by Midwest Research I n s t i t u t e , 425 Volker Boulevard, Kansas Ci ty , Missouri 64110, under Contract NAS8-25510, "Development of Lubr i ca t ing O i l s S u i t a b l e f o r Use With Liquid Oxid izers , f o r t h e George C. Marshall Space F l i g h t Center o f t h e Nat ional Aeronaut ics and Space Adminis t ra t ion. The work was adminis te red under t h e t e c h n i c a l d i r e c t i o n of the Science and Engineer ing As t ronau t i c s Laboratory of the Marshal l Space F l i g h t Center w i t h M r . C. F. Key a c t i n g as t h e Cont rac t ing O f f i c e r ' s t e c h n i c a l r e p r e s e n t a t i v e .
This r e p o r t covers work conducted from 1 June 1970 t o 31 August 1970.
The work a t Midwest Research I n s t i t u t e w a s designated 3380-C and w a s c a r r i e d ou t by Mr. R. L. E l l i o t t and M r . L. W. Breed, who ac t ed as P r i n c i p a l I n v e s t i g a t o r , under t h e supe rv i s ion of D r . C. C. Chappelow, Jr., Head, Organic and Polymeric Materials Sect ion.
Approved f o r :
MIDWEST RESEARCH INSTITUTE
H. M. Hubbard, D i rec to r Phys ica l Sc iences Div is ion
14 September 1970
3 - i i
TABLE OF CONTENTS
Page
Abstract......................... . . . . 3-1
I. Introduction . . . . . . . . . . . . . . . . . . . . . . . 3-2
11. Properties of Modified Fluorine-Substituted Esters . e e . 3-3
. . . . . . . . . . . . A. jD-Alkoxyacetic Acid Esters 3-3 B. Unsymmetrical Esters. . . . . . . . . . . . . . . . 3-5 C. Ester Blends. . . . . . . . . . . . . . . . . . . . 3- 7 D. Water Corrosion . . . . . . . . . . . . . . . . . . 3-9 E. Samples.. 3-11 . . . . . . . . . . . . . . . . . . . .
111. Anticipated Work . . . . . . . . . . . . . . . . . . . . . 3-11
IV. Experimental Part. . . . . . . . . . . . . . . . . . . . . 3-11
A.
B.
Preparation and Characterization of &‘--Alkoxyacetic
Preparation and Characterization of Modified Acids . . . . . . . . . . . . . . . . . . . . . . 3-11
Fluorinated Esters from L-Alkyloxyacetic Acids
Preparation of Fluorinated Esters from tJ’--Alkanols and Various Polyols . . . . . . . . . . . . . . . 3-15
C. and Various Aliphatic Acids . . . . . . . . . . . 3-15
D. Determination of Lubricant Properties . . . . . . . 3-15 E. Water Corrosion Tests . . . . . . . . . . . . . . . 3-21
List of References. . . . . . . . . . . . . . . . . . . . . . . . 3-22
LIST OF TABLES
Table Title Page
I Pour Points, Evaporation Rates, Viscosities, and Viscosity Indexes for New Modified Fluorine- Substituted Esters. . * - . a e . * . . . * \. e . * 3-6
I11 Properties of Unsymmetrical Esters. . e e e . It 3-8 IV Pour Points and Evaporation Rates of Blends of
Fluorinated Ester Fluids. . . . . . . . . . . . . . . 3-8 V Water Corrosion Data. . . e e . . e . a e e e e 3-9 VI Preparation of $-Alkyloxyacetic Acids: First Method e 3-12
I1 Experimental Four-Ball Wear Test Data e . . a e e 3-7
3-iii
TABLE OF CONTENTS (Concluded)
LIST OF TABLES (Concluded)
Table Title
VI1 Preparation of x-Alkyloxyacetic Acids: Second Method. VI11 Properties of $--Alkyloxyacetic Acids a . . . IX Preparation of Modified Fluoro-Substituted Esters From
$--Alkyloxyacetic Acids and Various Polyols . . . e e
X Properties of Modified Fluoro-Substituted Esters. . e .
LIST OF FIGURES
Figure Title
1
6
7
8
9
10
11
12
Corrosion on 52-100 Steel Balls in the Presence of Fluorine-Containing Fluids and Water. e . . e e . . .
Infrared Spectrum of $--Propyloxyacetic Acid (Liquid) . Infrared Spectrum of &-Pentyloxyacetic Acid (Liquid) e
Infrared Spectrum of $--Heptyloxyacetic Acid (Liquid) e
Infrared Spectrum of l,l,l-Trimethylolethane Tris- ($--propyloxyacetate) (Liquid). . e . . . . . . . . .
Infrared Spectrum of l,l,l-Trimethylolpropane Tris- ($'--propyloxyacetate) (Liquid) e . . e e . . . . . . .
Infrared Spectrum of 2,2-Dimethylolpropane Bis-(L- propyloxyacetate) (Liquid). . . . . . . . e . . . . .
Infrared Spectrum of l,l,l-Trimethylolethane Tris- (i-pentyloxyacetate) (Liquid). e . e a . . . e
Infrared Spectrum of l,l,l-Trimethylolpropane Tris- (L-pentyloxyacetate) (Liquid). e e . . . e . . e
Infrared Spectrum of 2,2-Dimethylolpropane Bis($-- pentyloxyacetate) (Liquid). . e e . e . . . . e e e .
Infrared Spectrum of 2,2,3,3,4,4-Hexafluoropropanediol Bis($--pentyloxyacetate) (Liquid) a e . . e . .
Infrared Spectrum of 2,2-Dimethylolpropane Bis($-- heptyloxyacetate) (Liquid). . . e , e a e e
Page
3-13 3-13
3-16 3-17
Page
3- 10 3-14 3-14 3-14
3-18
3-18
3-18
3-19
3-19
3-19
3-20
3-20
3-iv
ABSTRACT
The sea rch has continued f o r f l u o r i n a t e d ester compositions, which have improved vacuum c o m p a t i b i l i t y b u t a t t h e same t i m e have s a t i s f a c t o r y pour p o i n t s and LOX-compatibility, A series of neopentyl polyol esters o f g - a l k o x y a c e t i c a c i d were prepared and screened as f l u i d s f o r use i n g r e a s e compositions du r ing t h e c u r r e n t r e p o r t period. Although t h e evaporat ion rates of t h e f l u i d s were cons ide rab ly lower than those of t h e c - a l k y l 3- me thy lg lu t a ra t e s , o i l s w i th much g r e a t e r v i s c o s i t i e s a t room temperature and h ighe r pour p o i n t s were obtained. Two of t h e experimental f l u i d s had pour p o i n t s as low as -40'F. Improved v i s c o s i t y indexes i n t h i s series seemed t o be r e l a t e d more t o t h e higher v i s c o s i t i e s than t o t h e s t r u c t u r e i t s e l f . When mixed wi th t r i c r e s y l phosphate, t h e f l u i d s performed sa t i s - f a c t o r i l y on the wear tests. Samples of two of t h e f l u i d s have been f o r - warded t o Marshall Space F l i g h t Center fo r LOX-compatibility t e s t i n g . f l u i d compositions based on unsymmetrical esters and on blends of s p e t r i - c a l e s t e r s showed no improvement over t he pure esters i n t h e i r u s e f u l t e m - pe ra tu re range. I n a d d i t i o n a l work, two samples of L - a l k y l S-methylgluta- rates con ta in ing 2 w t . % of t r i c r e s y l phosphate and thickened wi th Vydax 1000 have been prepared and forwarded f o r LOX-compatibility screening:. Also, c o r r o s i o n tests have shown t h a t b i s ( c - p e n t y l ) 3-methylglutarate has a marked e f f e c t on t h e r educ t ion o f r u s t i n g on 52-100 s t ee l b a l l s when t h e b a l l s are s t o r e d w i t h t h e f l u o r i n a t e d f l u i d i n t h e presence of water.
Other
3-1
I INTRODUCTION
The o b j e c t i v e of t h i s work i s p r imar i ly the opt imiza t ion o f the l u b r i c a t i o n p r o p e r t i e s and vacuum c o m p a t i b i l i t y o f s e l e c t e d f l u o r o e s t e r based g reases that were prepared and s tud ied under Contract NAS8-21269. The spe- c i f i c goa l s and t h e accomplishments under Cont rac t NAS8-21269 were reviewed i n Quar te r ly Progress Report No . 1. were presented and publ ished r e p o r t s were c i t e d t o show t h a t a d d i t i v e modi- f i c a t i o n of t h e f l u o r o e s t e r b a s e d g r e a s e s adequate ly improved the wear p r o p e r t i e s i n l u b r i c i t y t es t s and t h a t ox ida t ion-cor ros ion i n h i b i t o r s prob- a b l y were not necessary w i t h i n t h e p ro jec t ed s e r v i c e range of up t o 300'F. The c h i e f l i m i t a t i o n on t h e f l u o r o e s t e r compositions w a s t h e i r r e l a t i v e l y h igh evapora t ion ra te a t 300°F and consequent ly the i r poor vacuum compati- b i l i t y . S a t i s f a c t o r y p r o p e r t i e s of these l u b r i c a n t s inc lude low pour po in t , LOX-compatibility, h y d r o l y t i c s t a b i l i t y , noncorrosiveness , n o n r e a c t i v i t y w i t h aluminum under shear, and ease o f g e l a t i o n t o a grease.
I n that r e p o r t experimental r e s u l t s
A t a p r o j e c t conference a t Marshal l Space F l i g h t Center , 23 June 1970, i t w a s determined t h a t g rease requirements could be d i f f e r e n t i a t e d wi th r e s p e c t t o systems requirements: S ince LOX systems r e q u i r e 10% pour poin t performance, but can accept a compromise on the evapora t ion test , t h e g e l l e d L - a l k y l 3-methylg lu ta ra te g reases can be considered s a t i s f a c t o r y ; l u b r i c a n t requirements f o r GOX systems demand some a d d i t i o n a l s t r u c t u r a l mod i f i ca t ion of t h e esters t o achieve t h e evapora t ion requirement, bu t t h e requirements are s a t i s f i e d i n t h e low temperature range by esters having pour p o i n t s i n t h e range o f -45 t o -50°F. On t h e b a s i s of a survey o f t h e c u r r e n t l y manufactured l u b r i c a n t s and t h e experimental work so f a r com- p l e t ed under t h i s c o n t r a c t , i t i s improbable t h a t a s i n g l e l u b r i c a n t can m e e t t h e requirements f o r bo th systems.
The cont inued e f f o r t has l a r g e l y been d i r e c t e d toward achiev ing s t r u c t u r a l mod i f i ca t ion o f t h e esters i n o rde r t o s a t i s f y t h e requirement f o r the second c lass of l u b r i c a n t s , A decrease i n t h e v o l a t i l i t y of the o i l r e q u i r e s mod i f i ca t ion of the chemical s t r u c t u r e i n one of t h e fol lowing ways: A decrease i n the e x t e n t of f l u o r i n a t i o n ; an inc rease i n t h e formula weight; o r the i n t r o d u c t i o n of p o l a r groups i n t o the s t r u c t u r e . The spe- c i f i c mod i f i ca t ions r e q u i r e tha t the LOX-compatibility not be compromised and t h a t t h e low temperature v iscometr ic p r o p e r t i e s be maintained,
During t h e second q u a r t e r , a f i r s t series o f s t r u c t u r a l l y modi- f i e d f l u o r o e s t e r o i l s were prepared and some of their p r o p e r t i e s were de- termined. The p a r t i c u l a r s t r u c t u r a l mod i f i ca t ion s e l e c t e d m e t one o r more of t h e s t r u c t u r a l c r i te r ia f o r decreas ing the v o l a t i l i t y of t h e f l u i d w i t h - ou t being de t r imen ta l t o the low temperature v iscometr ic p rope r t i e s . The fol lowing i s the genera l ized s t r u c t u r e f o r t h i s new class of f l u i d s .
3-2
FF3 CH3CH C-O-CH2-CF-O-CH2 (CF2) .H] e 2
F lu id A n = 4 Flu id B n = 6
The s t r u c t u r e increased t h e formula weight through the a d d i t i o n of an ether l inkage and a f l u o r i n e - s u b s t i t u t e d a l i p h a t i c group, y e t maintained a h igh degree of f l u o r i n e conten t .
The pour po in t o f F lu id A w a s -65'F and of F lu id B -50°F, bo th h igher than t h e pour p o i n t s o f t h e unmodified esters. However, t h e e x t e n t of t h e i n c r e a s e was minimal cons ide r ing t h e i n c r e a s e i n t h e formula weight o f t h e f l u i d . B i s ( d - n o n y l ) 3-methylg lu ta ra te , t h e next h ighe r homologue i n t h e unmodified ester series r epor t ed t o f r e e z e a t +77"F.1/ I n select- i n g the modified s t r u c t u r e s , i t had been a n t i c i p a t e d tha t t h e presence o f the e t h e r l inkage i n the molecular s t r u c t u r e would a l low f r e e r cha in c o i l - i ng and consequent ly b e t t e r tempera ture-v iscos i ty p rope r t i e s . i n t h e inc rease i n v i s c o s i t y as t h e temperature i s lowered would r e s u l t i n a lower pour poin t . index improvement was observed i n F l u i d s A and B.
A lower ra te
Contrary t o expec ta t ions , no tendency toward v i s c o s i t y
V o l a t i l i t i e s w e r e reduced, bu t no t s o much as might b e expected from the formula weight i nc rease . A f t e r 1 hr. a t 300"F, F lu id A showed a 5% evapora t ion whereas b i s ( d - a m y l ) 3-methylg lu ta ra te showed a 23% evapora- t i o n ; F lu id B showed about a 1% evapora t ion as compared wi th 5% evapora t ion f o r bis(jr'--heptyl) 3 -methylg lu ta ra te . However, a n o v e r a l l comparison of pour p o i n t s and evapora t ion rates i n d i c a t e s t h a t the p r o p e r t i e s f o r F lu id A and b i s ( L - h e p t y l ) 3 -methylg lu ta ra te are much t h e same and tha t no sub- s t a n t i a l improvement w a s e f f e c t e d i n t h e s t r u c t u r a l modi f ica t ion .
The chief e f f o r t dur ing t h i s q u a r t e r has involved t h e syn thes i s and screening of a second chemical ly modified series of esters, the s t r u c - t u r a l c lass favored f o r t h e LOX system l u b r i c a n t .
11. PROPERTIES OF MODIFIED FLUORINE-SUBSTITUTED ESTERS
A. L -Alkoxyace t i c Acid Esters
A series o f newly modified ester f l u i d s incorpora ted an e t h e r s t r u c t u r e and allowed a n i n c r e a s e i n the p ropor t ion of hydrogen and the formula weight of t h e molecular s t r u c t u r e . These f l u i d s , which a r e s t r u c - t u r a l l y s imilar t o the commercial neopentyl po lyol esters, were prepared by condensing neopentyl po lyo l s w i t h L - a l k o x y a c e t i c ac ids .
3-3
H(CF2) 4CH20Na + ClCH2C02H - H(CF2) 4CH20CH2C02H Structural variations included the products of the esterification of rlr)- propyloxyacetic acid, d-pentyloxyacetic acid, or J'--heptyloxyacetic acid with l,l,l-trimethylolethane, l,l,l-trimethylolpropane, 2,2-dimethylolpro- pane, or 2,2,3,3,4,4-hexafluoropentane-1,5-diol. Specific procedures for the preparation of the esters are described in the experimental portion of this report.
Compound No.
1
2
3
4
5
6
7
8
Structure
CH3C [CH202CCH20CH2 (CF2) 2H]3
CF2 [CF2CH202CCH20CH2 (CF2) qH]2
Name - l,l, 1-trimethylolethane bis(c-propyloxyacetate)
1,l,l-trimethylolpropane bis(JL1-propyloxyacecate)
2,2-dimethylolpropane bis(JL1-propyloxyacetate)
l,l,l-trimethylolethane bis(d-pentyloxyacetate)
l,l,l-trimethylolpropane bis(&-pentyloxyacetate)
2,2-dimethylolpropane his($--pentyloxyacetate)
2,2,3,3,4,4-hexafluoro- pentane-l95-diol bis(JL1- pentyloxyacetate)
2,2-dimethylolpropane bis(j'--heptyloxyacetate)
3-4
I n i t i a l l y , a smal l q u a n t i t y o f each of the f l u i d s w a s prepared and screened f o r pour po in t , evapora t ion ra te , and v i s c o s i t y . Subsequently, l a r g e r samples of F lu ids 5 and 6 were prepared and submitted f o r LOX-com- p a t i b i l i t y screening.
The r e s u l t s o f t he de te rmina t ions o f f l u i d p r o p e r t i e s are sum- marized i n Table I. I n t h e de te rmina t ion of evapora t ion rates, some prob- l e m s i n r e p e a t a b i l i t y r equ i r ed ref inements i n the procedure; t he re fo re , new va lues f o r s e v e r a l commercial materials and previous ly prepared f l u i d s a r e provided f o r comparison. Some previous ly determined pour po in t s and vis- c o s i t i e s f o r t h e same f l u i d s a r e a l s o included.
Only t h e pour po in t s o f t h e dimethylolpropane d e r i v a t i v e s were s a t i s f a c t o r y , va lues of -40 and -45" being obta ined , and evapora t ion rates were lower than t h e evapora t ion r a t e s f o r $'--alkyl 3-methylglutarate . I n t h e new series, somewhat h ighe r v i s c o s i t y indexes were observed, bu t the improvment appeared t o be r e l a t e d t o the h igher v i s c o s i t i e s of these o i l s a t 100 and 210°F r a t h e r than t o changes i n t h e v iscometr ic p r o p e r t i e s inher - e n t i n the s t r u c t u r a l modi f ica t ion . Four-ba l l wear tests on two of the f l u i d s , w i t h and wi thout added t r i c r e s y l phosphate are summarized i n Table 11. T r i c r e s y l phosphate a f forded adequate wear p r o t e c t i o n t o these two f l u i d s .
I f t h e o v e r a l l p r o p e r t i e s of the f l u i d s i n Table I are compared, t h e pour po in t s , evapora t ion ra tes , and v i s c o s i t i e s of 2,2-dimethylolpro- pane bis(tJ'--pentyloxyacetate) (Compound 6 ) , tris($'--amyl) t r i c a r b a l l y l a t e , and Krytox 143AA are roughly equiva len t . now appears thattris($--amyl) t r i c a r b a l l y l a t e and bis(hydroxymethy1)propane bis(tf--pentyloxyacetate) as pure substances are t h e b e s t candida tes as GOX system l u b r i c a n t s . There i s cons iderable advantage i n materials c o s t s i n t h e second compound, b u t r e s u l t s have not y e t been obtained on i t s LOX- compa t ib i l i t y .
On the b a s i s of t h e s e da t a , i t
I n t h e ear l ie r work, t he t r i c a r b a l l y l a t e ester showed 0/20 re- a c t i o n s i n t h e LOX c o m p a t i b i l i t y test. The evapora t ion rates of n e i t h e r o f t hese compounds approach the requirement of less than 1% a t 300°F and less than 5% a t 400"F, y e t t he i r evapora t ion rates are not g r e a t e r t han those of t h e b e s t commercially a v a i l a b l e materials.
B. Unsymmetrical Esters
It i s r epor t ed that lower pour p o i n t s and evapora t ion rates a t no s a c r i f i c e i n the v i s c o s i t y o r v i s c o s i t y index can be achieved i n the a l i p h a t i c d i e s t e r series t h r o u g h - t h e use of esters w i t h mixed l igands . This improvement was observed by Cohen and o t h e r s i n comparing the p r o p e r t i e s
3-5
TABLE I
POUR POINTS, EVAPORATION RATES, VISCOSITIES, AND VISCOSITY INDEXES FOR NEW MODIFIED FLUORINE-SUBSTITUTED ESTERS
Wt. % Evaporation C omp o u nd 300 * 2°F Pour Point Viscosity cSt. ASTM Viscosity
Index No e 1 Hr. 6 Hr. OF 210°F 100°F
1 -- 3.0 -5 14.41 339.4 - 18 I- -- -- 2 -" 1.4 -5
m.p. 33-37°C
3 -- 13.7 -40 4.92 50.89 -31
4 -- 0.7 - 10 16.32 374.3 5
5 -- 1.4 - 10 16.12 349.6 13
6 -I 5.4 -45 6.03 74.17 - '+9 -- .".m -I -e -- -- 7
m.p. 66-70°C
8 -- 5.9 -35 7.02 91.03 -12
Bis (L-amyl) 3-methylglutarate 10.5 < -90 2.78 16.27 -59
Bis (L-heptyl) 3-methylglutarate 2.4 14,6 - 75 3.57 26.11 -80
Tris (L-amyl) tricarballylate 0.9 4.8 -45 6.78 86.23 -25
-- -- -- Fomblin L 13.0 37.3 -80
-- -- -- Krytox 143AA 1.8 6.1 -50
-- -- _ I Krytox 143AZ 9*4 32.0 - 70
3-6
TABLE I1
EXPERIMENTAL FOUR-BALL WEAR TEST DAT&
Add i t i v e Wear Scar Diameter
(mm.) a t 50 Kg.
2,2-Dimethylolpropane bis(jr'--pentyloxyacetate)
F lu id
No ne 2 w t . % T r i c r e s y l phosphate
l , l , l -T r ime thy lo le thane t r i s ( d - p e n t y l o x y a c e t a t e
F lu id
None 2 w t . % T r i c r e s y l phosphate
0.75 0.56
0.69 0.38
- a / Two hours a t 147", 600 rpm, 52-100 s teel b a l l s .
of t h e unsymmetrical esters w i t h b lends of pure esters con ta in ing t h e same propor t ions o f a l coho l and a c i d l i g a n d s . l /
The p r o p e r t i e s of two unsymmetrical f l u o r a t e d esters are r epor t ed i n Table 111. A comparison o f the pour p o i n t s and evapora t ion rates of the esters i n Table I11 w i t h the corresponding v a l u e s f o r s i m i l a r symmetrical esters i n Table I i n d i c a t e the va lues f o r t h e unsymmetrical esters are not s i g n i f i c a n t l y d i f f e r e n t from the va lues f o r the symmetrical esters, pro- v ided t h e formula weights are about the same,
C. Ester Blends
The p o s s i b i l i t y o f achiev ing a wider u s e f u l f l u i d range through t h e u s e o f b lends of f l u o r i n e - s u b s t i t u t e d esters was a l s o considered. Be- cause o f t h e s i m i l a r i t y i n chemical composition, such b lends should be compatible i n a l l proport ions. It w a s o f p a r t i c u l a r i n t e r e s t t o determine i f t h e -10'F pour po in t of l , l , l - t r i m e t h y l o l e t h a n e tris($--pentyloxyacetate) could b e e f f e c t i v e l y lowered by a small p ropor t ion of a low pour poin t f l u i d wi thout s e r i o u s l y i n c r e a s i n g i t ' s low evapora t ion rate (0.7% i n 6 h r e ) . I n some mixtures t h a t were i n v e s t i g a t e d and are r epor t ed i n Table I V , changes i n pour p o i n t s and evapora t ion rates were both roughly p ropor t iona l t o the percentage of each component i n t h e blends. produced compositions w i t h p r o p e r t i e s as f avorab le as t r i s ( g - a m y l ) t r i- c a r b a l l y l a t e o r 2,2-dimethylolpropane bis(jll-pentyloxyacetate),
3-7
None of the combinations
TABLE I11
PROPERTIES OF UNSYMMETRICAL ESTERS
Pour Point Evaporation Rate Components in Ester Preparation (OF) (6 Hr. at 300 f2OF)
Tricarballylic acid (0.085 mole) g-Pentyl alcohol (0.17 mole) f--Heptyl alcohol (0.099 mole)
2,2-Dimethylolpropane (0.10 mole) -Jrl.-Pentyloxyacetic acid (0.10 mole) L-Heptyloxyacetic acid (0.10 mole)
-40 3.8
-45 7.3
TABLE IV
POUR POINTS AND EVAPORATION RATES OF BLENDS OF FLUORINATED ESTER FLUIDS
Fluids A. l,l,l-Trimethylolethane tris(d-pentyloxyacetate) B. Bis($--amyl) 3-methylglutarate C. Bis(L-hepty1) 3-methylglutarate D. 2,2-Dimethylolpropane bis(j'--pentyloxyacetate)
Blend Composition (wt. X ) Wt. % Evaporation at Pour Point - A - B - C - D 300°F, 6 Hr. (OF)
-- I-
-_ 10 25 50 100 -- 10
25 50 100
0.7 5.5 14.0 26.6 10.5 (1 hr.) 2.2 4.8 9.8 14.6 1.2 1.9 3.2 5,4
- 10 - 15 -35 -50
< -90 - 15 -25 -45 - 75 - 15 -25 -30 -45
3-8
D. Water Corrosion
An additional property of $--alkyl 3-methylglutarate fluids was examined during this report period. When small quantities of water were mixed with the commercial and many of the experimental fluids and a ball bearing was stored in the mixture at 60"F, rusting occurred as if water alone were present, showed no rusting, although some pitting was observed. The results of a series of tests run for 91 hr. are summarized in Table V. In a second series of experiments, the water corrosion tests were run for much longer periods. The appearances of the bearings after the tests are shown in Figure 1.
A similar test with &!-pentyl 3-methylglutarate fluid
Fluid
Tris (g-amyl) tricarballylate
Bis(L-heptyl) 3-methylglutarate
Bis(d-amy1) 3-methylglutarate
TABLE V
WATER CORROSION DAT&
Fir st Sample
Loose rust
Loose rust
Slight staining
2,2-Dimethylolpropane bis(d- pentyloxyacetate
Krytox 143AA
Fomblin L
Mineral oil
Heavy staining
Loose rust
Loose rust
Loose rust
Second Sample
Loose rust
Loose rust
Slight pitting
Slight staining
Loose rust
Loose rust
Slight staining and pitting
- a/ 52-100 Steel balls in the presence of water and the test fluid for 91 hr. at 60°F.
3-9
C
D
F i g u r e 1 - Corrosion on 52-100 S t e e l Balls i n the Presence of Fluorine- Containing F l u i d s and Water: A. Water o n l y (14 days a t 6OOC); B. PR 143AA ( 4 days a t room temperature) ; C. hep ty l ) 3-Methylglutarate (22 days a t 60O); E. Bis(#--pentyloxytetrafluoro- propyl) 3-Methylglutarate (22 days a t 6 0 " ) .
Fomblin L (22 days a t 60"); D. B i s ( 2 -
3- 10
E. Samples
During this report period, the following lubricant samples were forwarded t o Marshall Space Flight Center for LOX-compatibility screening.
Bis(tf--pentyloxytetrafluoropropyl) 3-methylglutarate9 24 g.
Bis (2 -hep ty loxy te t r a f luo ropropy l ) 3-methylglutarate, 24 g.
Bis(tf--pentyl) 3-methylglutarate (containing 2% tricresyl phosphate) thickened with 16% Vydax 1000, 194 g.
Bis($'-heptyl) 3-methylglutarate (containing 2% tricresyl phosphate) thizened with 16% Vydax 1000, 219 g.
2,2-Dimethylolpropane bis(f--pentyloxyacetate), 181 g.
l,l,l-Trimethylolethane bis(c-pentyloxyacetate), 142 g.
None of the results of these tests has been received,
111. ANTICIPATED WORK
After the work on characterizing the fluids discussed in this report is complete, the final report covering the work under the entire program will be prepared. When the results of LOX-compatibility testing is complete, recommendations can be made concerning the fluid which most nearly meets the specified requirements.
IV. EXPERIMENTAL PART
A. Preparation and Characterization of d--Alkoxyacetic Acids
Two procedures were employed for preparing these acids. The results of preparations in which the 1]LL-alkanol was first treated with sodium hydride and subsequently with chloroacetic acid are reported in Table VI, The following summarizes the conditions for the two larger preparations, The sodium hydride dispersion in mineral oil, mixed with 800 ml. of ether, was treated with the tJ'--alkanol over a 2 hr, period, and then the chloro- acetic acid was added over a 1.5 hr. period. After the mixture cooled to room temperature and was stored overnight, 400 ml. of 25% hydrochloric acid was added and the ether layer was separated and dried over sodium sulfate,
3-11
TABLE V I
PREPARATION OF d-ALKYLOXYACETIC ACIDS : FIRST METHOD
Compound &-Propyl $'--Pentyl Chloroac e t i c No e Alcohol Alcohol Acid
1 232.0 g, (1.76 moles)
2
2
94.5 g. (0.80 mole)
102.1 g. 18.9 g. (0.44 mole) (0.20 mole)
408.3 g. 75.6 g. (1.76 moles) (0.81 mole)
Sod i d / Y i e l d Hydride (%)
38.4 g. 89 (1.60 moles) (136 g.)
9.6 g. 83 (0.40 mole) (96 g.1
38.4 g. 84 (1.60 moles) (196 g.)
a / Used a s a 55% d i s p e r s i o n i n mineral o i l . - When t h e e t h e r was evaporated, a f i r s t vacuum d i s t i l l a t i o n gave t h e a c i d contaminated wi th mine ra l o i l . A f t e r t h e mine ra l o i l w a s e x t r a c t e d wi th petroleum e t h e r , b.p. 35-60', t h e ac id w a s p u r i f i e d by f r a c t i o n a l d i s t i l - l a t i o n under vacuum.
I n t h e second method, the &'--alkanol, c h l o r o a c e t i c a c i d , and aqueous sodium hydroxide were heated t o g e t h e r i n one s tep. The r e s u l t s of t hese p r e p a r a t i o n s are summarized i n Table VII. The following i s a repre- s e n t a t i v e procedure. a c e t i c a c i d w a s added t o a mixture of t h e $--alkanol and sodium hydroxide dur- i ng 1.5 h r . an exothermic r e a c t i o n occurred. The mixture was r e f luxed over- n igh t , cooled, and n e u t r a l i z e d w i t h 20% aqueous hydroch lo r i c ac id . A f t e r t he lower l a y e r w a s s epa ra t ed , washed w i t h two p o r t i o n s of 20% aqueous hy- d r o c h l o r i c ac id , and two p o r t i o n s of water, t he a c i d w a s p u r i f i e d by f r a c - t i o n a l d i s t i l l a t i o n .
When an aqueous s o l u t i o n of t h e sodium s a l t of chloro-
The p r o p e r t i e s and t h e r e s u l t s o f t h e c h a r a c t e r i z a t i o n of t h e s e a c i d s a r e summarized i n Table V I I I .
3-12
TABLE V I 1
PREPARATION OF I~'-ALKYLOXYACETIC ACIDS: SECOND METHOD
Alcohol Compound C h l o r o a c e t i c g - P e n t y l X - H e p t y l Water Y ie ld Recovered
No. Acid Alcohol A l c o ho 1 NaOH (ml.) (7,) (7,)
2 18.9 g. 51.0 g. (0.20 mole) (0 .22 mole)
2 378 g. 1 ,020 g. (4 .00 moles) (4 .40 moles)
3 189 g. (2.00 moles)
88 g. 44 27 42 (0.22 mole) (16 9.1
176 g. 1,000 50 45 (4.40 moles) (585 g . )
730 g. 88 g. 500 20 64 (2.20 moles) (2.20 moles) (154 8.1
TABLE V I 1 1
PROPERTIES OF h'-ALKYLOXYACETIC ACIDS
Compound B o i l i n g P o i n t 20 Analyses LFound/(calcd) I I n f r a r e d F Calcd. fo r A n a l y s i s
F igu re 2
n - H - C - D roc (m.)i - No.- a /
'gHgF4'3 llr/ 92-93 (0.90) 1.3697 31.48 3.05 40.98 134-136 (9) (31.59) (3 ,18 ) (39.98)
2 134-135 (10) 1.3565 29.08 2.03 52.23 7H6F803 F i g u r e 3 (28.98) (2.09) (52.39)
3 128-130 (0.3) 1.3471 27.73 1.62 58,56 CgH6F1203 F i g u r e 4 (27.71) (1 .55) (58.44)
- a / - b /
For i d e n t i f i c a t i o n of Compound Nos., see Tab les V I and V I I . Reported, b.p. 109-114" (24 mm.), ng6 1.3632. (Ref. 2 ) .
3- 13
4300 3000 2000 1500 1200 1000 900 800 700 C M ’
Figure 2 - I n f r a r e d Spectrum of $‘--Propyloxyacetic Acid (Liquid) I
100
- 80
tif 5
a
Z 60
5 2 40
20 ai I-
0 3000 3000 2000 1500 1200 1000 900 800 700
CM ‘
Figure 3 - I n f r a r e d Spectrum o f $--Pentyloxyacetic Acid (Liquid)
I
WAVELENGTH (MICRYIS) 3 ‘ 4 5 6 7 8 9 11 12 13 14 15
100 100
- 80 80 * ! 60 60 4
9 40 40
20 20
-
5 d I-
0 0
C M ‘ 4000 3000 2000 1500 1200 1000 900 800 700
Figure 4 - I n f r a r e d Spectrum of f--Heptyloxyacetic Acid (Liquid)
3-14
B. Preparation and Characterization of Modified Fluorinated Esters From L-Alkyloxyacetic Acids and Various Polyols
The quantities, described in Table IX, of tf--propyloxyacetic acid or &-pentyloxyacetic acid and l,l,l-trimethylolethane, 12191-tri=- methylolpropane, 2,2-dimethylolpropane9 or 2,2,3,3,4,4-hexafluoropentane- 195-diol were dissolved in toluene to which was added sulfuric acid. The mixtures were heated from 4-17 hr. until the specified quantity of water had been collected in a Dean-Stark trap. After cooled mixtures were washed sequentially with water, aqueous potassium carbonate, and water, the toluene was distilled off and the esters were purified by fractional distillation. The characterization and properties of these fluids are reported in Table X.
C. Preparation of Fluorinated Esters from $--Alkanols and Various Aliphatic Acids
1. Bis($--amyl) 3-methylglutarate: A mixture of 114.0 g. (0.78 mole) of 3-methylglutaric acid, 408.0 g. (1.76 moles) of g-amyl alcohol, 600 ml. of toluene and 4 g, of sulfuric acid was refluxed for 21 hr. A total of 31.6 ml. of water (calcd,, 28.1 ml.) was collected in a Dear-Stark trap. When the cooled mixture was added dropwise to 200 ml, of water, the lower phase separated and was added dropwise successively to 200 ml, of 5% potassium carbonate and 200 ml. of water. After the solvent and traces of water were removed on a rotary evaporator, fractional distillation of the residue gave 411.4 g. (92%) of bis(&-amyl) 3-methylglutarate9 b,p. 123" (0.07 mm.), n6' 1.3605 [reported b.p. 130-132O (0.03 me), ng0 1.3606],2/
2. Mixed &-pentyl, g-heptyl ester of tricarballylic acid: When the procedure in the preceding paragraph was followed, 15.0 g. (0.085 mole) of tricarballylic acid, 40.1 g, (0.17 mole--2% excess) of $'--pentyl alcohol, and 32.8 g. (0.099 mole--14% excess) of J@--heptyl alcohol, heated in 50 ml. of toluene with 0.2 g. of sulfuric acid for 20 hr, gave 4,6 ml. (calcd., 4.6 ml.) of water. Purification and fractional distillation of the product gave 41 . (53%) of the mixed ester, b,p, 176-184' (0.07 mm,), pour point -40"F, n$ 1,3580.
D. Determination of Lubricant Properties
Fluid viscosities were determined by ASTM method D 445-65 and viscosity indexes were calculated by method D 2270-64, pour points followed ASTM method D 97-57. mined on the four-ball wear test at a load of 50 kg. after 2 hr, at 146" with 52-100 steel balls at 600 rpm,
The method for Wear scar diameters were deter-
3- 15
TABLE IX
PREPARATION
OF MODIFIED FLUORO-SUBSTITUTED ESTERS FROM ~'-ALKYLOXYACETIC ACIDS AND VARIOUS POLYOLS
Water
[MI. Fo
und
(Calcd) 1
3.3
(3.2
)
3.5
(3.2
)
3.5
(3.6
)
3.0
(2- 7
)
11.5
(10.8)
6.0
(5.4
)
(2.7
) 3.
0
3.1
(2.7
)
19.9
(1
9.8)
3.0
(2.7
)
4.0
(3.6
)
3.9
(3.6
)
Toluene
(ml . )
50
50
50
50
50
50
50
50
3 00 50
50
50
Yield
2-Pr
opyl
oxy-
acetic Acid
38.0
g.
(0
.20
mole)
38.0
g
. (0.20 mole)
38.0
g.
(0.2
0 mole)
d- Pent yloxy-
acetic Acid
46.4
g.
(0
.16
mole)
190 g.
(0.6
6 mole)
95 g
. (0
.33 mole)
46.4
g
. (0
.16
mole)
46.4
g
. (0.16 mole)
351
g.
(1.21
moles)
46.4
g.
(0.16
mole)
d-He
ptyl
oxy-
Trimethylol-
Trimethylol-
Dimethylol-
Hexafluoro-
Sulfuric
propane
pentanediol
Acid (a)
acetic Acid
ethane
propane
Compound
No. 1 2 3 4 4 4 5 6 6 7 8 9
7.2
g.
(0.0
59 mole)
0.25
- al
8.0
g.
(0.0
60 mole)
0.25
10.4
g.
(0.10 mole)
0.25
52
(2
3 9
.)
6.0
g.
(0.0
49 mole)
24.0
g.
(0
.20 mole)
0.25
84
(3
9 g
.)
1.0
91
(171 9.)
12.0
g
. (0.10 mole)
0.25
0.25
6.
7 g.
(0.5
0 mole)
7.8
g.
(0.0
75 mole)
0.25
57.2
g.
(0.5
5 mole)
1.5
94
(337
9.)
15.9
g.
0.
25
(0,0
75 mole)
0.25
86
(49
9.)
85.8
g
. (0
.22 mole)
39.0
g.
(0.10 mole)
10.4
g.
(0.10 mole)
10.4
g.
(0.10 mole)
0.25
29.0 g.
(0.10
mole)
86
(6
4 8
.)
- a/ After
a portion of the product was lost through spillage,
18.1
g.
of the fluid was obtained.
TABL
E X
PRO
PER
TIES
OF
MO
DIF
IED
FLU
ORO
-SU
BSTI
TUTE
D
ESTE
RS
Pou
r E
vapo
rati
on
An
aly
sis
[Fou
nd/(
calc
d) ]
F C
alcd
fo
r -
H -
C n2
6 n2
0 C
ompo
und
Bo
ilin
g P
oin
t P
oin
t (%
a
fte
r 6
-
No .a
/ La
c (mm
. ) 1
("P
I h
r. a
t 30
0°F
) 26
D
1
212-
222
(0.0
8)
-5
3.00
1.
463
1,40
36
37.9
7 3.
84
35.3
8 C
20H
24F1
20g
(37.
74)
(3,8
0)
(35.
83)
2 22
3-22
4 (0
.09)
m
.p.
33-
1.40
1.
450
1.40
48
38.7
3 3.
94
35.4
7 C
21H
26F1
20g
37 "C
(3
8.78
) (4
.03)
(3
5.05
)
3 15
4-15
6 (0
.10)
-4
0 13
.69
1.36
7 1.
3962
40
.16
4.54
33
.71
C15
H20
F806
(4
0.18
) (4
.50)
(3
3.91
)
4 23
3-23
6 (0
.07
)bl
-10
0.67
1.
606
1.38
15
32.8
7 2,
62
48.5
2 C
2@24
l?24
0g
(33.
35)
(2.5
8)
(48.
69)
c*, I r
5
230-
240
(0.1
0)
-10
1.44
1.
582
1.38
22
33.6
4 2.
89
48.4
4 C
27H
26F2
40g
4
(34.
12)
(2.7
5)
(47.
98)
6 17
1-17
4 (O
.O8)
C/
-45
5.44
1.
514
1.37
60
35.2
4 2.
91
46.6
7 C
1gH
20F1
606
(35.
19)
(3.1
1)
(46.
89)
7 16
8-17
8 (0
.07)
m
.p.
66-
-- --
1.36
01
29.6
7 1.
96
55.1
5 C
lgH
14F2
206
70°C
(3
0.17
) (1
.87)
(5
5.27
)
8 17
9-18
5 (0
.06)
-3
5 5.
92
1.63
9 1.
3642
32
.80
2.51
34
.66
C23
H20
F240
6 (3
2.56
) (2
.38)
(5
3.75
)
, -
a/
For
id
enti
fica
tio
n o
f C
ompo
und
Nos
., se
e T
able
IX
.
-
b/ -
c/
B.p
. 35
9°C
(d.
t.a.
1.
Dec
ompo
siti
on p
rece
ds
bo
ilin
g a
t 38
5°C
.
Infr
ared
A
na 1
ys i
s
Fig
ure
5
Fig
ure
6
Fig
ure
7
Fig
ure
8
Fig
ure
9
Fig
ure
10
Fig
ure
11
Fig
ure
12
" 4500 3000 2000 1500 1200 1000 900 aoo 700
CM' Figure 6 - Infrared Spectrum of l,l,l-Trimethylolpropane Tris-
(g-pr opyloxyac eta te) (Liquid)
I
WAVELENGTH (MICRONS) 3 ' 4 5 6 7 8 9 10 11 12 13 14 15
100 100
- a0 a0 &
3 Z 60 4 t i m40 Z 4
- 60
40 cd I-
20 20
0 0
CM ' 4000 3000 2000 1500 1200 1000 900 800 700
Figure 7 - Infrared Spectrum of 2,2-Dimethylolpropane B i s - , (L-propyloxyacetate) (Liquid)
3-18
4500 3000 2000 1500 1200 1000 900 800 CM'
" 700
Figure 8 - Infrared Spectrum of l,l,l-Trimethylolethane , Tris($--pentyloxyacetate) (Liquid)
WAVELENGTH (MlCRq#S) 11 12 13 14 15 3 ' 4 5 6 7 8 9
Figure 9 - Infrared Spectrum of l,l,l-Trimethylolpropane Tris(L-pentyloxyacetate) (Liquid)
I
WAVELENGTH (MICRONS) 3 ' 4 5 6 7 8 9 10 11 12 13 14 15
100 100
- 80 80
60 5
- E
2
Z 60 6
r 2 40 40
I-
20 20
0 0
CM ' 4000 3000 2000 1500 1200 1000 900 800 700
Figure 10 - Infrared Spectrum of 2,2-Dimethylolpropane Bis($'--pentyloxyacetate) (Liquid)
3-19
I
WAVELENGTH I '
100
- 80 E P 60 i? 3
d 2 40
20 c
0 4000 3000 2000 1500 1200 1000 900 aoo 700
CM'
Figure 11 - Infrared Spectrum of 2,2,3,3,4,4-Hexafluoropropanedi Bis($--pentyloxyacetate) (Liquid)
I
WAVELENGTH (MICR$$lS) 11
100 100 3 i 4 5 6 7 8 9 12 13 14 15
- 80 a0 %
P 60 60 Q
I
I-
2 2 40 46 Q D: t
20 20
G 0
CM' 4000 3000 2000 1500 1200 1000 900 800 700
Figure 12 - Infrared Spectrum of 2,Z-Dimethylolpropane Bis- (d-heptyloxyacetate) (Liquid)
01
3-20
Evaporation rates represent the value obtained when about 2.5 g.
The temperature was de- of a fluid weighed in a 24 mm, diameter and 7 mm, deep aluminum dish was heated on a hot plate at 300 -f 2°F for 1 or 6 hr. termined with a thermocouple just touching the bottom of the pan.
E. Water Corrosion Tests
In a series of tests a mixture of 3.0 g. of a fluid and 0.15 g. of water was placed in a jar in contact with a 52-100 steel ball. steel balls used were not new and had been previously used on various four- ball wear tests, but all were corrosion free at the beginning of the tests. The following fluids were examined: PR 143AA; Fomblin L; bis(L-heptyl) 3-methylglutarate; and bis(2-~-pentyloxytetrafluoropropyl) 3-methylglutarate. The samples were stored at 60°C for at least 14 days, except for the PR 143AA fluid, which was stored for 4 days, All of the balls, except the ball in the bis(f--heptyl) 3-methylglutarate showed rusting during the storage period. Rusting was particularly heavy with water alone and with the PR 143AA fluid. Photographs of the steel balls are shown in Figure 1. The dark mark at the center of each ball is a reflection of the camera lens. A light reflection also shows on each ball.
The
A second series of tests is summarized in Table V. In duplicate experiments 52-100 steel ball bearings were contacted thoroughly with each of the following fluids and three drops of water were added. The samples were stored at 60" for a total of 91 hr. At the end of the test period, the ball bearings were examined for loose rust, staining and pitting.
3-21
LIST OF REFERENCES
1. G. Cohen, C. M. Murphy, J. G. O ' R e a r , J. G. Ravner, and W. A. Zisman, NRL Report 4066 (1952).
2 . Bucham Research Labora to r i e s , Ltd. , B r i t . P a t e n t , 873,244 (1962) C.A. Ih, 780 (1962).
3. L. W. Breed, J, C. Wiley, Jr., and C. F. Key, Ind. Eng. Chem. Prod. R e s . Develop., L, 53 (1970).
3-22
PROG
RAM
PLA
NN
ING
CH
ART
Lit
era
ture
Sur
vey
and
Pla
nn
ing
To
tal
Dec
. Ja
n.
Feb
. M
arch
A
pri
l M
ay
3une
July
&
S
ept.
Oct.
Nz
Man
-Hou
rs
---
2 00
Tes
tin
g a
nd
Ev
alu
atio
n
6
c
of
Mat
eria
ls
1,0
00
Lu
bri
can
t O
pt im
i za
t io
n
4
c
500
Dev
elop
men
t S
tud
ies
4
d
5 00
b
152
Rep
ort
s
Est
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DISTRIBUTION LIST
Q u a r t e r l y Proqress Reports , Con t rac t NAS8-25510
No. of Copies Rec i p i e n t
1
1
1
2
10
National Aeronaut ics and Space Admin i s t r a t ion George C . Marshal l Space F l i g h t Center Marshal l Space F l i g h t Center , Alabama 35812 At tn : A&TS-PR-M
Contract NAS8 -255 10 DCN l-X-50-20131(1F)
Nat iona l Aeronaut ics and Space Admin i s t r a t ion George C . Marshal l Space F l i g h t Center Marsha l l Space F l i g h t Center , Alabama 35812 At tn : A&TS-MS-IL
Contract NAS8-255 10
DCN l-X-50-20131(1F)
Nat iona l Aeronaut ics and Space Admin i s t r a t ion George C . Marshal l Space F l i g h t Center Marsha l l Space F l i g h t Center , Alabama 35812 A t t n : A&TS-MS-TU
Contract NAS8-2 5510 DCN 1 -X- 50-2 013 1 (1F)
Na t iona l Aeronaut ics and Space Admin i s t r a t ion George C. Marshal l Space F l i g h t Center Marshal l Space F l i g h t Center, Alabama 35812 A t t n : A&TS -MS-IP
Con t rac t NAS8-25510 DCN 1-X-50-2 013 1 (1F)
Nat ional Aeronaut ics and Space Adminis t ra t ion George C. Marshal l Space F l i g h t Center Marshal l Space F l i g h t Center , Alabama 35812 A t t n : Sm-ASTN-RRI
Con t rac t NAS 8 -2 5 5 10 DCN 1-X-50-2013 1 (1F)
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