Processes for synthesizing borohydride compounds

Details Processes for synthesizing borohydride compounds Processes for synthesizing borohydride compounds

2001-04-12

2003-02-25

Vollano, Jean F. (Department: 1621)

Chemistry of inorganic compounds

Boron or compound thereof

Hydrogen and metal or ammonium containing

C423S287000, C423S288000

Reexamination Certificate

active

06524542

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to processes for synthesizing borohydride compounds, and more particularly to processes of synthesizing borohydride compounds with reduced energy requirements.
BACKGROUND OF INVENTION
Environmentally friendly fuels (e.g., alternative fuels to hydrocarbon based energy sources) are currently of great interest. One such fuel is borohydride, which can be used directly as an anodic fuel in a fuel cell or as a hydrogen storage medium (e.g., hydrogen can be liberated by the reaction of sodium borohydride with water, which produces sodium borate as a byproduct). As with all fuels, acceptance of borohydride in the commercial market is partially dependent on the availability of industrial scale quantities.
Typical industrial processes for the production of sodium borohydride are based on the Schlesinger process (Equation 1) or the Bayer process (Equation 2), which are both described below. Equation 1 illustrates the reaction of alkali metal hydrides with boric oxide, B
2
O
3
, or trimethoxyborate, B(OCH
3
)
3
, at high temperatures (e.g., ca. 330 to 350° C. for B
2
O
3
and 275° C. for B(OCH
3
)
3
). These reactions, however, provide poor molar economy by requiring four moles of sodium to produce one mole of sodium borohydride.
4NaH+B(OCH
3
)
3
→3NaOCH
3
+NaBH
4
  (1)
Na
2
B
4
O
7
+16Na+8H
2
+7SiO
2
→4NaBH
4
+7Na
2
SiO
3
  (2)
The primary energy cost of these processes stems from the requirement for a large excess of sodium metal (e.g., 4 moles of sodium per mole of sodium borohydride produced). Sodium metal is commercially produced by electrolysis of sodium chloride with an energy input equivalent to about 17,566 BTU (18,528 KJ) per pound of sodium borohydride produced. In contrast, the hydrogen energy stored in borohydride is about 10,752 BTU (11,341 KJ) of hydrogen per pound of sodium borohydride. The Schlesinger process and the Bayer process, therefore, do not provide a favorable energy balance, because the energy cost for producing sodium significantly outweighs the energy provided from sodium borohydride as a fuel.
Furthermore, in view of the large quantities of borohydride needed for use, e.g., in the transportation industry, these processes would also produce large quantities of waste products such as NaOCH
3
or Na
2
SiO
3
. Since these byproducts are not reclaimed or reused, further energy and expense is required to separate and dispose of these by-products.
Improvements found in the prior art are basically simple modifications of the Schlesinger and Bayer processes represented by equations (1) and (2). Accordingly, such improvements also suffer from the disadvantages stated above, and do not provide any improved energy efficiency or an environmentally sensitive option for disposal of the by-products.
In view of the above, there is a need for improved and energy efficient industrial scale manufacturing processes for producing borohydride compounds. In addition, there is a need for industrial scale processes that reduce or avoid the production of large quantities of waste products that require further disposal.
Accordingly, it is an object of the present invention to provide industrial processes of producing borohydrides with improved energy efficiency. It is also an object of the present invention to provide processes of producing borohydride with reduced levels of unwanted waste products.
SUMMARY OF THE INVENTION
The present invention provides processes for producing large quantities of borohydride compounds, which overcome the above-described deficiencies. In addition, the efficiency of the processes of the present invention can be greatly enhanced over the typical processes for producing borohydride compounds.
In one embodiment of the present invention, a process is provided for producing borohydride compounds, which includes: (A) reacting carbon dioxide and water with a Y-containing compound (i.e., a metaborate compound) of formula YBO2 to obtain a bicarbonate compound of the formula YHCO
3
and boron oxide; (B) converting YHCO
3
into Y
2
O, carbon dioxide, and water; (C) reacting the boron oxide with carbon and a halide compound of formula X
2
to obtain BX
3
and carbon monoxide; (D) reacting the BX
3
with hydrogen to obtain diborane and HX; and (E) reacting the Y
2
O with diborane to obtain YBO
2
and YBH
4
. In accordance with the invention, Y is a monovalent cationic moiety such as an alkali metal (e.g., H, Li, Na, K, Rb, Cs, and Fr), a pseudo-alkali metal (e.g., T1), an ammonium ion (NH
4
+
), or a quaternary amine of formula NR
4
+
; R is independently hydrogen, or straight or branched C
1
to C
4
alkyl group; and X is a halide (F, Cl, Br, I, or At).
In another embodiment of the present invention, a process is provided for producing borohydride compounds, which includes substituting steps (B1) and (E1) for steps (B) and (E): where (B1) entails reacting the YHCO
3
to produce Y
2
CO
3
, carbon dioxide, and water; and (E1) entails reacting the Y
2
CO
3
with diborane to produce YBH
4
, YBO
2
, and carbon dioxide. Y and X are the same as defined above.


REFERENCES:
patent: 2469879 (1949-05-01), Hurd
patent: 2534533 (1950-12-01), Schlesinger et al.
patent: 2684888 (1954-07-01), Pryde
patent: 2720444 (1955-10-01), Banus et al.
patent: 2741539 (1956-04-01), Banus et al.
patent: 2855353 (1958-10-01), Huff et al.
patent: 2889194 (1959-06-01), McElroy et al.
patent: 2926989 (1960-03-01), Pryde
patent: 2926991 (1960-03-01), Bragdon
patent: 2928719 (1960-03-01), Berner et al.
patent: 2934401 (1960-04-01), Hansley et al.
patent: 2938767 (1960-05-01), Huff et al.
patent: 2939762 (1960-06-01), Berner et al.
patent: 2942935 (1960-06-01), King et al.
patent: 2955911 (1960-10-01), Edwards et al.
patent: 2964378 (1960-12-01), Brown et al.
patent: 2969274 (1961-01-01), Kyllonen
patent: 2970894 (1961-02-01), Chappelow et al.
patent: 2974015 (1961-03-01), Peterson
patent: 2983574 (1961-05-01), Nigon
patent: 2983575 (1961-05-01), Cohen et al.
patent: 2985510 (1961-05-01), Kalb
patent: 2992072 (1961-07-01), Huff et al.
patent: 2992266 (1961-07-01), McElroy
patent: 3002806 (1961-10-01), Governale et al.
patent: 3014059 (1961-12-01), Bush et al.
patent: 3014060 (1961-12-01), Bush et al.
patent: 3021197 (1962-02-01), Clark et al.
patent: 3022138 (1962-02-01), Clark et al.
patent: 3028221 (1962-04-01), Schechter et al.
patent: 3029128 (1962-04-01), Chamberlain
patent: 3042485 (1962-07-01), Edwards
patent: 3047358 (1962-07-01), Jenkner
patent: 3077376 (1963-02-01), Schubert et al.
patent: 3079224 (1963-02-01), Huff
patent: 3152861 (1964-10-01), Logan et al.
patent: 3161469 (1964-12-01), Ashby et al.
patent: 3164441 (1965-01-01), Goerrig
patent: 3171712 (1965-03-01), Edwards et al.
patent: RE25777 (1965-05-01), Schubert et al.
patent: 3216797 (1965-11-01), Murib et al.
patent: 3219412 (1965-11-01), Hunt et al.
patent: 3222121 (1965-12-01), Jenkner et al.
patent: 3306704 (1967-02-01), Campbell et al.
patent: 3433605 (1969-03-01), Knorre et al.
patent: 3459514 (1969-08-01), Johnston et al.
patent: 3468630 (1969-09-01), Raisor et al.
patent: 3471268 (1969-10-01), Bontempelli et al.
patent: 3473899 (1969-10-01), Cooper
patent: 3474899 (1969-10-01), Carlsson et al.
patent: 3505035 (1970-04-01), Horn et al.
patent: 3511710 (1970-05-01), Jung et al.
patent: 3515522 (1970-06-01), Pecak et al.
patent: 3993732 (1976-11-01), Filby
patent: 4002726 (1977-01-01), Filby
patent: 4070261 (1978-01-01), Merritt et al.
patent: 4904357 (1990-02-01), Sharifian et al.
patent: 4931154 (1990-06-01), Hale et al.
patent: 5294423 (1994-03-01), Lorthioir et al.
patent: 5886229 (1999-03-01), Corella et al.
patent: 6433129 (2002-08-01), Amendola et al.
patent: 86108142 (1988-06-01), None
patent: 148173 (1972-05-01), None
patent: 947702 (1956-08-01), None
patent: 949943 (1956-09-01), None
patent: 950062 (1956-10-01), None
patent: 950846 (1956-10-01), None
patent: 1036222 (1958-08-01), None
patent: 1053476 (1959-03-01), None
patent: 1058478 (1959-06-01), None
patent: 1095797 (1960-12-01), None
paten

Affiliated with

Also associated with

Rating

Processes for synthesizing borohydride compounds does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Processes for synthesizing borohydride compounds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Processes for synthesizing borohydride compounds will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3138474